Monday, August 30, 2010

Sunday, August 29, 2010

Openbiosprog-spi: Open Hardware and Free Software USB-based programmer for SPI chips

openbiosprog-spi is a fully Open Hardware and Free Software USB-based programmer for SPI chips, e.g. those used as BIOS chip in recent mainboards.

The user-space source code is part of flashrom (GPL, version 2), the schematics and PCB layouts are licensed under the CC-BY-SA 3.0 license and were created using the open-source Kicad EDA suite (GPL, version 2).

Downloads

The schematics, PCB layouts, and other material is available from gitorious:

$ git clone git://gitorious.org/openbiosprog/openbiosprog-spi.git

The flashrom source code is available from:

$ svn co svn://flashrom.org/flashrom/trunk flashrom

The openbiosprog-spi 0.1 Gerber files and drill file are also available for download here (for convenience):

http://randomprojects.org/wiki/images/a/a8/Openbiosprog-spi-0.1-gerber.zip

Design

This is intended to be a simple, fast, USB-based SPI chip programmer.

It uses the FTDI FT2232H chip as basis for USB as well as for handling the actual SPI protocol in hardware (MPSSE engine of the FT2232H).
Attaching the SPI chip:
- There's a DIP-8 socket on the device so you can easily insert the SPI chip you want to read/erase/program.
- Optionally, if you don't want a DIP-8 socket, you can solder in a pin-header with 8 pins, which allows you to connect the individual pins to the SPI chip via jumper wires or grippers/probes.
The hardware is designed using the open-source Kicad EDA suite (GPL, version 2), and is released under the CC-BY-SA 3.0 license.
The software on the host side is flashrom (GPL, version 2).
The PCB board dimensions are 44mm x 20mm.

Usage

(flashrom output partly shortened for better readability)

Identify the SPI chip:

$ flashrom -p ft2232_spi:type=2232H,port=A
Found chip "Winbond W25x80" (1024 KB, SPI) at physical address 0xfff00000.

Read chip contents:

$ time flashrom -p ft2232_spi:type=2232H,port=A -r backup.bin
Found chip "Winbond W25x80" (1024 KB, SPI) at physical address 0xfff00000.
Reading flash... done.

real    0m9.758s
user    0m0.640s
sys     0m0.432s

Erase chip:

$ time flashrom -p ft2232_spi:type=2232H,port=A -E
Found chip "Winbond W25x80" (1024 KB, SPI) at physical address 0xfff00000.
Erasing flash chip... SUCCESS.

real    0m41.785s
user    0m26.518s
sys     0m0.812s

Write chip (includes an automatic erase step and another read step for write success verification):

$ time flashrom -p ft2232_spi:type=2232H,port=A -w newimage.bin
Found chip "Winbond W25x80" (1024 KB, SPI) at physical address 0xfff00000.
Writing flash chip... Erasing flash before programming... Erasing flash chip... SUCCESS.
done.
Programming flash... done.
COMPLETE.
Verifying flash... VERIFIED.          

real    1m9.150s
user    0m26.946s
sys     0m1.788s

See the respective flashrom page (or consult the flashrom manpage) for details.

Friday, August 27, 2010

CD/DVD Parts Container

Penny Stove

Wayback

I share this stove to help help keep canisters out of landfills.
If you want to thank me, please send a check to a wilderness preservation fund such as:
Sierra Club, 85 Second Street, 2nd Floor, San Francisco, CA 94105
www.sierraclub.org

Penny Stove Instructions

The following buiilding instructions are brief, so -

* For building advise, stove options & lighting instructions, please visit
Frequently Asked Questions section below.

* If you use a very small pot, also visit 1/2 Penny Small Pot Stoves page.

* For detailed step-by-step instructions using only one Heineken can visit
Stove Instructions by Bill Waite Penny page.

* For flash instructions go to the Original Instructiions.

Materials you need:
Three 12 oz. Heineken cans (or two and a pop can). Two drip irrigation stakes- or wire hanger, bike spokes etc.. One ft. of bailing wire- or solid copper wire etc.. One drier vent tube- or heavy foil etc..
Tools you need:
Although a good scout could make one with his knife, the following tools will do a cleaner job:
large scissors, hand drill with 1/16" bit, needle nose pliers. At least one friend to drink the extra beer.

The Heineken can has raised bands that provide perfect diameter and spacing for all of the parts. Three cans are needed to make the stove. Another kind of pop or beer can actually works better for for the top/base. Cut with a knife and finish with large scissors.

Top/base should be shorter than shown (about 1/2" tall). The Burner (3/4" tall) is cut off just below the first band. The Fuel Cup is cut off at the top of the band (making it about 1 1/4" tall). The Simmer ring uses a top band and top flat section (about 1" tall).

The burner has a 1/4" hole as show, or three 1/16" holes, drilled in the center and six 1/16" holes spaced outside the ring drilled vertically from outside the can (see lines). Needle nose pliers were used to make 12 dimples or folds. These must end 1/4" short of the top edge. Then, a small hole punch was used to make holes in the folds to release hot gases to the inside of burner. 12 are shown, but 6 (every other fold) tested just as good. If you don't have a punch, just drill 12 - 1/16" holes instead... it will work fine.

* WARNING
Apparently some new cans have numbers stamped on the bottom (Brian Kent found that at least some of the 12-pack cans do NOT have numbers). These bumps may keep the penny from sealing the burner opening allowing fuel to run under the penny before the stove gets hot or before you can light it. It may also let flame into the cup causing a POP that spreads burning alcohol.
The solution is to sand the Burner cup to remove the number bumps - 320 sand paper works fine. You can also use a socket and hammer to tap the penny into the Burner center to help it seal the opening - it should hold the fuel in the top cup indefinitely. Another solution is to use a regular pop (sprite) or beer (Guinness) can for the burner - (see Can I use a pop can burner without crimps? below).

In addition, a good safety solution is to drill 3 or 4 - 1/16" holes in the burner center instead of the single 1/4" hole. These must fit under the penny. This may keep flames out of the burner even if the penny is removed Mike Martin recommended this change.

The burner is carefully tapped into the fuel cup until it hits bottom and provides a tight seal. A clean press fit between the burner and the cup is important because it keeps primer fuel from draining and heated gasses from leaking while burning.

The top/base is used as an insulated support for the fuel cup. This helps keep a stable temperature in the stove and provides protection under the stove. I now use a soda can for the top/base and cut it down until the stove sits firmly without tipping. This picture was taken just as priming fuel was burned up and the stove was starting to light.

Two "U" shaped wires wrapped together with thin wire form the pot pupport. Drip irrigation stakes work best. Three legs make a stable base- supporting the pot at least 1" above the burner. My windscreen is a section of aluminum Dryer vent. Tests show that screen is not necessary in good weather and only increases one quart boil times by 30 seconds.

Modefied 2 quart Open Country pot (6oz.) is large enough to melt snow, sterilize water, wash clothes, or shampoo hair. The stove, support, and screen fit inside the pot (total 8.3oz). An 8oz. bottle of alcohol (about 12 fully cooked meals) fits inside along with a spork, cup, scrub pad, soap, matches, lighter, salt, pepper, coffee, tea, and towel. Total cook kit is less than 20oz.

The top/base can be used as a cover for storage or to seal the stove and save fuel between meals. I now use the bottom of a pop can with one 1/16" hole in the bottom- it's lighter and fits tight without getting stuck - no need for the handle. Simmer ring slips over the bottom (not shown in this photo). The package is small enough to store inside of a plastic camp cup.

To Top

Frequently Asked Questions
What if the fuel runs under the Penny too soon?	Apparently some of the new cans have numbers molded on the bottom. These bumps may keep the penny from sealing the burner opening allowing fuel to run under the penny before the stove gets hot. If this happens it sometimes lets flame enter the opening causing a disconcerting POP as fumes inside the Cup blow off the penny - this is not good. Also, sometimes the stove jets will not light because fuel has run into the cup before it is heated. The easiest solution is to use a a smooth soda can or beer can for the burner. Brian Kent found that at least some of the Heineken cans that come in the 12-pack boxes do NOT have numbers stamped into the bottom. Or, you can sand the Burner cup to remove the number bumps - 320 wet/dry sand paper works fine. You can also use a socket and hammer to tap a nickel into the Burner center to to help make a seat. Or, rub the penny to grind a sooth surface. Either way, it must hold the fuel in the top cup indefinitely. Also, pennies produced after 1982 are not copper and don't work as well... so save the old ones :~) Olivier Loria and Norman Stoddard suggested using a quarter instead of a penny to span the bottom number dents. I tried this and it seemed to work as expected. Because the quarter is heavier, the stove builds a bet more pressure, so the jets burn a little higher and the center flame a bit smaller. A nickel also worked as expected. Both also took more time to drain priming fuel into the cup. Another fix from Matt Myers: "I cut a square piece of high temperature flute tape (from another stove design that wasn't very efficient) just a bit larger than the penny and covered the 1/4 inch hole. After smoothing the tape, I put the penny in the proper place and with a socket from my tool bench that was just a little smaller than the penny. I then tapped the socket with a hammer so that it would indent the tape and make a perfect seal. Then I just punched the 1/4 " hole again with a drill bit and finally had a great seal."
What if I don't drink?	You can make the stove with only one Heineken can and use soda or beer cans for the burner and base (see Bill Waite Penny Stove System ). Or, make it entirely from soda cans - see Can I use soda cans instead? below. Or, buy a six-pack of Heineken for a friend and have them save the cans. Make them a stove, they may even pay you back (you can supply the old penny).
How does it work?	Burning fuel in the center and outer ring of the burner heats the Cup and fuel. The heat causes fuel in the the center to run under the penny into the Cup and start to boil. Fuel in the outer ring lights the six Jets as gasses are released from boiling fuel in the Cup. The pot and wind screen reflect the heat and accelerate the heating process. The Base insulates the hot Cup to maintain a stable boil. Jets continue to heat the Burner and lip of the Cup, increasing the boil and producing a full flame. Windy conditions will blow flames into the Cup lip increasing the boil and flame size. As heat builds up, pressure forces gasses under the penny to produce a central flame. As the fuel level falls (or Simmer Ring is added), pressure falls and the penny seals to force all gasses out the six Jets maintaining stable heat to the Cup and optimum flame size to the pot.
What kind of alcohol should I use?	I use Denatured alcohol for tests but use Evearclear ethanol alcohol on the trail because I can drink it, use it to sterilize cuts, or to disinfect my hands and water containers - one bottle does it all!. DO NOT USE Rubbing Alcohol, it burns dirty and contains water that could cause a steam bubble and blow the penny off of the stove. Below are notes on extensive stove burn tests by Mike Martin: Heet (Yellow Bottle) -- 99% Methanol, burns beautifully with little odor or flareups. Readily available at gas stations and auto parts stores. But, with only approx. 9700 BTU/lb, not as weight efficient as other fuels. Sunnyside Denatured Alcohol (from Home Depot) -- Primarily Ethanol at around 12700 BTU/lb. Burns Ok, but fumes are bothersome to me. S-L-X Denatured Alcohol (also from HD) -- Also primarily Ethanol. Burns just like the Sunnyside stuff, but the fumes are not as bad IMO. Heet (Red Bottle) -- 99% Isopropanol, potentially over 14000 BTU/lb if you could get it to burn cleanly. But, burns with yellow flame and leaves sooty deposit on pots. Swan 99% Isopropyl Alcohol -- Burns just like the Red Heet. Typical rubbing alcohol smell. Everclear -- 95% Ethanol -- Not available everywhere. Very Expensive. Soot problems are minor compared to Isopropanol. E85 (85% ethanol/15% gasoline) I do not recommend using this, however, David Lubertozzi found It produced: "very fast start, goes from "sterno" mode to full jets in about 15 sec, but burns with longer, richer jets (more orange flame, more black on the pot) for about 60 sec, then gradually goes back to normal. What I think happens is that the more volatile gasoline components come off as vapor first, since you're boiling the liquid you're essentially distilling the mixture. While probably not as efficient as pure EtOH, it seems pretty safe, may be a good alternative for improving cold weather start-up, and is cheap if you have an E85 station nearby - but you can't drink it ‡}" Solving the invisibility problem* A little table salt to any alcohol will make it visible, but Don Trapp "mixed 50% S-L-X Denatured Alcohol (from Home Depot) with 50% Isopropanol alcohol (Red Bottle of Heet from the gas station). The mixture makes enough yellow flame to make the fire visible, without creating as much soot as pure isopropanol gives. A mix of 73% (1 quart) SLX and 27% (1 bottle) Isopropanol worked as well. I got the idea from Daniel Perlman, who patented a mixture that includes water, in US Patent 5,858,031.
What is the best way to light the stove?	To boil 2 cups: 1. Set up the stove, support, pot, and windscreen (leaving at least 1/4" gap around the pot) on a flat, clean, solid, nonflammable surface. Then, remove the pot to access the stove. 2. With the penny covering the hole(s), fill the center burner until fuel runs over the top and completely covers the jet holes. This will be about 1/2oz. (15ml.) of fuel. Some fuel may drain down the jet holes, this is normal and will actually help the stove to heat faster. Immediately put the pot back on the support. 3. Carefully, without bumping the stove, use an open flame to light the burner from the edge of the cup - you may not see the flame so be careful. NEVER LIGHT THE STOVE UNLESS THE JETS ARE COVERED WITH FUEL. As stove warms, any fuel covering the penny will run into the cup and begin to boil. Fuel in the outside ring will light the jets. Burn time should be 5 to 5.5 min.. To fill for very cold water or to slow cook 2 cups: 1. With the penny covering the hole(s), fill the center burner to the very top of the stove - this will be about 2/3oz. (20ml.) 2. After the pot has boiled (about 4 min.) remove the pot and drop the simmer ring over the burner (small side down). The simmer ring MUST be used with the pot. It will insulate the cup, slow the burn and simmer for about 5 times as long. If you're cooking real rice or dehydrated foods, you can put the simmer ring on before you light the stove. This will make the total burn time with 2/3 oz. 18 to 20 minutes and re-hydrate the food as it heats. To fill for boiling one quart: Fill the top, then side the penny aside to drain all the burner center fuel into the cup. Cover the hole(s) with the penny and fill the top again. This will total about about 1.2 oz. (40 ml.) of Fuel. To fill for maximum burn time: Slide the penny aside and fill the cup to the filler hole(s). Slide the penny over the hole and fill the burner top. this will total 1.5 -2 oz. of alcohol. This much fuel will take a long time to prime but heats like a "normal" stove as it heats the stove. Jon Powel said his boiled "8 cups of water, 16 minutes, boils for an additional 3 minutes before 1.5oz fuel runs out." With the simmer ring it will burn for about 40 minutes. * WARNING In five years, several people have informed me that when first lighting the stove, the penny popped off and alcohol blew out of the stove. I believe that this could be caused by moisture remaining in the stove after construction, or coating in the inside of new cans. So, be careful out there....and, just to be safe, NEVER LIGHT THE STOVE UNLESS THE JETS ARE COVERED WITH FUEL.
How can I light the stove when it's really cold?	Sometimes, if it's really cold, the primer fuel in the outer ring burns out before the fuel boils and jets light. When this happens, I put my hand over the burner to make sure it is out. Then, add a few drops of fuel in the outer ring and light the stove again. If you know that cold may be a problem, put a pot lid or bend a foil cup under the stove. Dribble a few drops of alcohol into this before lighting the stove. Then, light the fuel under the stove after you light the stove. This will heat the cup from the outside and also add more insulation under the stove to protect it from the cold ground. Another option was suggested by Chris Harper in North Wales: "I added some rockwool type insulation materiel around the outer part of the burner just as a starter wick, fill the cup and drain into hole, and add a squirt around the outer ring in the wick and light. It will light and run straight away after burning off the wick supply. Brilliant, as little as 10ml (we are quasi decimal here in UK!) will boil a 300ml mug."
How can I boil in less time?	The fast boil times are the result of the stoves efficiency - speed was not an original design goal. But, if you want to race your friends, or need that morning coffee a few seconds faster, there are two things you can do - make it prime faster and/or burn hotter. Each will make the process a little less convenient and efficient however. As Jeff has shown, a priming pan (or foil cup) under the stove will help achieve a faster full jet burn. Just light off a few drops of fuel under the stove to heat the cup from the outside as it is priming. To make it burn hotter, you can move the jets a little to the outside and closer to the top cup rim (or tweak the jets that way with a drill bit). This will make the cup hotter, and force more fuel under the penny at full burn. Oh, yes, you can also use a thinner pot, a larger diameter aluminum pot, or a pot with a black bottom (soot is good).
Why are there so few jets and why are they so big?	Several years ago, when I designed the stove, most high performance stoves had 24 tiny jets. Now many are down to just eight. I can only assume that this is based on testing as was my choice of six + the center burner used under full burn. David Lubertozzi use a #60 bit to make a Penny with twelve -0.040" burner holes to equal the same area as the original and found that it "didn't perform any better than six at 1/16", in fact a bit worse." Many have tried using multiple tiny holes with the same result. The Penny jets produce a flame size about the same as those on a Viking stovetop. Obviously Viking thinks that big jets must be an effective way to burn gas and transfer heat to a pot and my tests confirm this. They are also less affected by wind, pot distance, altitude and the dirt that accompanies all backpacking trips. A gas stovetop burner has an open center to allow all jets 360° access to fresh oxygen. Alcohol stoves cannot have a central air supply. The Penny, unlike other pressure stoves, has spaced jets to allow oxygen to flow 360° around the flames and also to feed the central flame (just starting in this photo). Because the full pot bottom is heated by fully mixed fuel it heats faster and burns more efficiently.
How does the Simmer Ring work?	Do NOT extinguish the stove, just drop it on (small end down) whenever you want to slow the burn.* It shields the edge of the Cup from the flame, cools the Cup, and slows the alcohol boil. It also reduces the air supply and raises the smaller flame much closer to the pot for maximum efficiency. For maximum simmer time, you can start the stove with the ring in place. The ring only continues to slow the burn with a pot in place to block excess oxygen from the jets. Without the pot, you may melt the ring! If you want a faster simmer, cut about 1/8" off of the top of the Ring to let in more air. To simmer longer, make it a little taller (or lower the pot). A 3/4" high ring, (1/2" below the pot) seems to be a good place to start. Tests show that 1-1/3 oz. (40ml) will burn for about 40 - 50 min. 2/3 oz. (20ml) will burn for 18 - 20 min. 1/3 oz. (10ml) will burn for about 10 min. - heat 2 cups of water for perfect tea - no boil however. Phil Perkins so far holds the unofficial simmer efficiency record: "I just got done with a simmer test and found by using the original simmer ring I was able to simmer hot water for over 56 minutes. I used 1.25 oz. of denatured alcohol."
How can I drop the simmer ring on without burning Myself?	Have your friend do it... Or, practice a few times before you light the stove. Or, after you miss, push it over with a stick. Or, leave a tab connected to the top of the ring when you cut it.... hard to pack that way however. Or, if you know you will be simmering, and are not in a hurry, just put it on after you fill but before you light the stove.
What is the best way to insert the Burner?	I have always just tapped the burner into the Cup. I set a small measuring cup on top and tap with a wooden spoon. Recently, Mark Warren proposed this brilliant idea: "When I assembled my Penny alcohol stove, I did some quick calculations and figured that if I heated the fuel Cup (to 400°F in my toaster oven) and cooled the Burner (to 0°F in my freezer) I would have - in theory - 0.002in of clearance to slide the burner in easily. It was easy in practice, however, I've only assembled one using this technique. Here are my calculations... http://www.editgrid.com/user/mwarren/Aluminum_can_walls" You may need to use oven mitts!
How can I evenly space the six jet holes?	You could make a pattern but this is not necessary. If they look evenly spaced, they are way good enough. This is what I do: 1. Use a Sharpie to mark the center of the burner. Spin the burner to check and expand the dot until it is in the center. 2. Make two dots on the rim on top and bottom of the Burner (180°). Sit a straight edge vertically on top of the stove and make sure that all three dots are aligned. Adjust one rim dot if necessary. 3. Evenly space two dots on each side. Use the straight edge to check these with the center dot and adjust opposite dots as necessary. 4. Transfer the final rim dot locations down to the outside of the rim and drill. Use alcohol to wipe off Sharpie marks.
How can I make perfect Burner crimps?	This is what I do: 1. Using the six jet holes as a guide, make three equally spaced crimps. Put needle nose pliers 1/4" short of the top and bend down almost 90°. Adjust to make symmetrical folds. 2. Make another full crimp in the center of each fold. Adjust all six to make the folds equal. 3. Add one more crimp in the center of each of the six folds. 4. Make sure that the crimps don't distort the top edge, and, that all the folds are inside the diameter of the top edge. I roll the burner edge on a table to flatten any creases or folds around the top edge so they will not crease the Cup when I tap it in. If this happens use JB Weld to fill the seam as described below.
Can I use a soda can burner without crimps?	Yes, it will work almost as well. Most soda cans are a little smaller in diameter. Phil Perkins "found that by using an 8 oz. Pepsi can as the burner you don't need to crimp it. It slides right in." The burner side wall should be shorter - between 3/8" and 1/2". A non-crimped Burner will not heat quite as fast and buckle if tapped to hard into the Cup, and any bends could cause a leak, so go easy. I still recommend a soda can burner WITH crimps because it gives you essentially a double wall stove. A soda can burner is thinner so I suggest that you seal the burner with JB Weld high temp. epoxy. First scrape or sand any coating from the seam and do as 'Cutman' describes here: "After I pushed the burner all the way into the fuel cup and seated it fully, then I mixed the JB and using a toothpick applied it at the junction of the two parts, sort of like "caulking" the seam. I think it helped "pressurize" the stove without having any effect on the priming. I was careful to keep the epoxy right in the joint, and did not let it go up the side of the fuel cup or onto the burner part with the six holes in it". Bob Mclaren had this fantastic solution: " I used a soda can for the burner insert without crimping. For an effective seal I used a few wraps of plumbers Teflon tape; easier than epoxy." Michael Hoernig said this: I remembered that a Guinness 14.9oz Draught can... fits snuggly into the small diameter portion of the Heineken can. The advantages are obvious, you still have to choke down a Heineken, but you can wash out the taste with a Guinness. It's a perfect fit. I sand the sides of the Guinness can slightly to remove the paint on the can and get a good heat transfer between the 2 side walls... then cut off the bottom to a height equal to the bottom of the ridge on the Heineken can. Since there is no gap between the sides of the fuel cup and the burner, I don't think there is any need to crimp or drill the sides of the burner... I found setting the burner up side down then pressing the fuel cup down over it works better then the other way around. The Heineken ridge, guides the burner into place, flip over and press down on the burner till it seats tightly. Jonathan Fairhead had this experience: " I got around to making the Penny Stove (using a soft drinks can (burner). No problems at all. Boils a pint in of water in just under 5 minutes (far quicker than my other stoves and with less fuel). I made some modifications (just to suit my own peculiar needs). Also, I'll probably JB Weld the stove (as you warned, it is weaker than the beer can)."
Can I use a burner without punched holes?	The holes in the burner crimps let hot gasses access to the inside of the burner where the jets are. In some rear situations, like a really high fill, this releases the pressure and keeps the burner cup gap from leaking. You can build it without those holes however and it works fine almost all of the time. If you don't have a small punch, I suggest that you just use the same 1/16" burner drill bit to drill these in each crimp near the top. It will work just as well.
How do you make the pot support?	I used drip tubing stakes - about 6" long U shaped wires used to tie down drip irrigation lines. First I straighten them, then I bent each into a wide U about 4" at the base and cut the vertical part to about 3" - this height will cut later to hold the pot at about 1 1/4" from the top lip of the stove. With my Base under the stove. my verticals are about 2 1/2" long. I use masking tape to hole the two parts together as I wrap the two together with bailing wire. For small pots I turn the support upside down. WARNING!!! This pot support could be VERY DANGEROUS when the pot is removed. Falling on the support could cause major damage. Always remove the support or turn upside down when not cooking.
Can I use other pot supports?	You can use any of the great pot support ideas found on the Web but it must let in lots of air and not reflect heat back to the stove. Also, make sure that the pot is at least 1" from the top of the cup rim. A little more distance will heat faster, simmer shorter and be more susceptible to the wind. Less distance will heat much slower and use much more fuel. I like the double "U" support because it allows full flame contact with the pot and full air supply to the flame, and, does not suck heat from the pot or reflect heat back to the stove. It also folds to fit into almost any pot and keeps the pot from sliding. Also, it lets me slide the burner in or out and there are advantages to having the wind shield separate from the support. Milton Barker "used wire cutters to cut a section of light gauge “hog” wire in sufficient length to form a circular pot support... and you don’t have the concern of stab wounds. It is best to pack this base in a pot or it will be flattened even though it can be reshaped." Damien Tougas made the beautiful support below, and says: "I am quite happy with how the design turned out, it doesn't weigh too much (1.75 oz on my kitchen scale), so far it seems to be very stable, strong, and durable. I built it using 1/4" aluminum rod and 1/2" aluminum tubing both purchased from Home Depot. I had to drill out the tubing to widen the internal diameter, but I think I found a place online where I could get thinner-walled tubing which could eliminatethat problem." It contains three identical modules and could be made with steel drip stakes. A beautiful stove with polished fuel cup and 3 - 1/16" center holes.
Can I use the BIG 24 oz. cans?	Yes, it makes a great base camp, boat, camper, or winter stove. Jesse Stovall followed the instructions but used big cans and says: "I made my stove from 24 oz heiniken can seeing that was the only size they had at the store. I made them using your design just with the larger cans. With it i was able to get 16 oz to boil in 3:20 and 32 oz in 5:45. I was truly impressed with how fast it boiled such a large amount of water. My one and only complaint was that I didn't find this website before I spent 45$ on an MSR pocket rocket, thanks again. " James Mullins of Ottawa reports from Canada: ... "I used the 710ml Hieny can. Works even better with a longer burn time. Great for a larger pot. Great, just great. My trusty but equally hazardous Coleman is going to get a rest.... I used a round (Canadian) nickel instead of a penny, and followed the advice to put three small filler holes in the centre instead of big one.... I have already amazed one camping buddy who spent over $100 on a tricky, temperamental Hi tech stove that requires special hard to find fuel and container."
Can I use soda cans instead?	Yes, in fact a soda or regular beer can is best for the Top/base - it's lighter and fits better and doesn't get as stuck when used as a top. You can also use a soda can for everythig but the Cup - see Bill Waite Penny Stove System. A full soda can stove will work. But since the material is much thinner, it will not be as strong and it is harder to make. The Top/base must be bent out to fit over the Cup to function as a Top and should be about 1/2" tall. The Burner 3/4" tall, the Fuel Cup is about 1 1/4" tall, and the Simmer ring must be a strip about 3/4" tall cut out of the center of the can bent to sit on the Burner inside the Cup lip. Howard Burnside summed up his experience: "I've made several of these - the Heineken cans work best, and I used your penny idea with the Pepsi stove and it worked better than making the big open hole in the center..."
Can I use those strange British cans	David Elder from the UK worked out the problems with making the stove using those UK Heineken cans with different proportions and a raised label area. He has just loaded his suggestions on a blog. He made a simmer ring and everything - see image below. I suggest that you visit David at: http://pennystoveuk.wordpress.com
How can I make a small pot stove?	First, turn the pot support upside down. Then, light the stove with the Simmer Ring on. This will slow the burn but also focus the flame on the center of the pot. If you find the burn too slow, cut about 1/8" off of the top of the Ring to let in more air. Or try the optional "Bill Waite Simmer Ring" shown below to focus more flame into the center. Bill "...used a can opener to remove the inside end (the top) of a Heineken can (leaving the rim) and it works super...The finished diameter of the ring end of the can... would work well for smaller pans. Some can openers work better than others. This is the model that I've used for cutting the ends out of hundreds of cans. http://www.seniorshops.com/goodgripcano.html " Greg Vaillancourt was inspired by the Minibulldesign Nion2 that has jets positioned in pairs (right next to each other). Greg says that "This (6) jet configuration really works well. The flames are focused and burn with a nice clean blue flame. A 1/16th" bit was used to drill the jets." That wire pot support is holding a large Heineken can pot and the priming pan shown may be required to light using those internal jets. This may be the best small pot full size Penny so far and should even work with the simmer ring. Ken Schoenike made "...a stove using 4 holes for jets but inside the rim... this was a further help with my small diameter pot. .66 oz of alcohol will boil and simmer with no problem though the boil and total times are a bit longer that with the 6 hole model, which is what i would expect." I have melted the penny this way however and it is more difficult to light because the jets are separated from the outer ring priming fuel. Years ago, Lin McEnerny was the first to deal with this by using "...a darning needle in a cork to make the holes, resulting in smaller diameters, and I placed the holes just inside the lip instead of outside as Mark described. This actually pretty well eliminates flaming up the pot sides, takes just a minute more to heat the same amount of water but used less fuel." More good options are shown on the 1/2 Penny Instructions .
How can I fix a leak between the Cup and Burner?	This is a very low pressure stove so a perfect seal is not necessary. However, a small leak can sometimes let priming fuel in the outer ring run down into the cup before the jets are lit... this IS a problem. Usually the leak is caused by a small crease in the Cup produced by a Burner crimp. A leak can sometimes overheat and expand the Cup and make the fuel burn too fast. This can also keep the simmer ring from working. Here are some options if this is your problem: 1. Make sure the Burner is tapped all the way into the Cup. Sometimes it creeps up after the first few burns but will find a set and seal later. 2. Put the drill bit back into the jets and "bend" them to aim more to the inside of the stove. This will keep the flame from overheating and expanding the Cup. 3. For a trail fix, use a small stick to pack dirt (not sand) into the leaking area. 4 . Fill the gap with JB Weld high temperature epoxy (see "Can I make a burner without crimps?" above). 5. Spend 10 min. and make a new stove.
Can I use other wind screens?	Yes, tests show that a taller wind screen (or heat reflector) will sometimes improve efficiency and boiling times, but not as much as on other stoves. It is also much less affected by moving air. Also, this stove burns very hot and needs lots of air so make sure that intake holes and exhaust space around the pot are generous. I have found that a 3/4 wind screen works well for me. It has only a few small holes so I can really block the wind on one side yet still supply plenty of a air on the other. It also lets me check the fire and even slide the stove in and out of the pot support. Also, it fits in the pot and is stiff enough to maintain its shape and not move around in the wind. If I need more protection, I can always block the wind with found objects -a rock, my shoe, some foil, etc.. Notes from extensive stove burn tests by Mike Martin: "All of the unpressurized stoves were more sensitive to windscreen configuration than the Penny stoves for a couple of reasons: a) The pressurized jets are less suseptible to being blown around than the low-speed flames of the unpressurized stoves. b) The windscreen affects the temperature of the stove, and so affects the rate at which the fuel evaporates and burns. The penny regulator diminishes this effect by increasing the central flame if the stove starts to overheat. The central flame is located relatively far from the lip of the burner on the Penny stove, and so contributes less to heating the burner than the peripheral jets. c) The windscreen affects the amount of oxygen available to the burner, and thus the burn rate. Again, the Penny regulator offsets this effect if the stove gets too much oxygen."
How do you pack this thing?	Modified Open Country pot, stove in cup, 8 oz. fuel, windscreen, pot support, lighter, matches, salt/pepper, pot bail, spork, pot scrubber (bottom). Coffee, tea, coco, and a few snacks sit on top and the lid holds everything together. Ultrallight and ultracheep version using a $6 K-Mart Grease Pot - with lid, stove, support & windscreen = 5.5 oz.. Set up for a long trip with 8 oz. of fuel, spoon, salt, lighter, matches & tea = 15 oz.. I replaced the pot lid knob w/ cord for easy packing and added a bale wire from a paint can. Stove is wrapped in paper towel.
Where did the penny idea come from?	I just wanted an efficient stove that I could make on the trail. And, having used an Optimus 8R pressurized gas stove for years, I knew that sealed self-pressurizing stoves often overheat and/or burn slow at the end when heat is needed most - they can also be very dangerous. After messing around with jet and center hole sizes, making low and no pressure stoves (similar to the newer Vargo), using the bottom of two cans (like Photon Stove), using a crimped burner as a double wall (like Pepsi Stove), and spaced jets to simulate an air jacket (like Cat Stove ), I realized that a center hole of any size would alter jet height during the burn. One day, looking for a low-tech way to regulate pressure, I dropped on a penny and that was it - the perfect solution. The six 1/16" jets that I was using turned out to provide the perfect pressure combination for simmer and fast boil. Later, when I first saw the shape of the Heineken can, I knew it would could provide the lid, base, proper jet spacing, priming fuel area, and insulating simmer ring. I was a little surprised that the self-filling, self- measuring, and self-priming features actually worked however. So, I guess it came to me like most good ideas do, some combination of experience, persistence, and luck - mixed with necessity and laziness. As my friend Bill Jones once said - "If I had all the right stuff, I'd never be able to design anything"...
So...How DOES the fuel get under the penny?	It's all very technical and complex. My guess is that the surface tension drops as the alcohol gets hot and the copper and aluminum heat at different rates causing a shift. At that point, divine intervention takes over as your mate comes in to ask if you plan to burn the house down......
Who is Mark Jurey?	I'm an industrial designer and have been lightweight backpacking since before ripstop nylon - note recent pic of my 40 year old Stephenson tent and pack (2.5 lb. each). Over the years I survived heat, altitude, wind, rain, and an August blizzard that killed three heavily prepared packers. I learned valuable lessons about life and nature, including; If it can break, it probably will; The ultimate hi-tech solution is often the most basic; and, simple multi-use tools are the key to a happy and healthy adventure. Early back country experiences went on to influence all aspects of my life. I studied design with Henry Dryfuss and Peter Pearce, a student of Buckminster Fuller - pioneers in ergonomics, and preserving natural resources. Early hiking lessons helped me as a product designer. I took the adage "less is more" to the very edge - looking for simple ways to solve complex problems and still protect the environment - solutions that use minimum resources to perform an elegant dance with nature. I went on to develop everything from educational toys to solar homes, TV shows to toilet seats, and kites to architectural building systems. But, the Penny Stove may be the best expression of my design philosophy - the ultimate hi-tech solution, available to anyone on the planet with access to a penny, a pocket knife, and a trash can. As a student at UCLA, our motto was - "there are no consumers, only users". Mark Jurey NoTrace~NotRace My Backward Garden Learning to live and grow with nature JUREY.studio Recent design work and portfolio

Disclaimer & Warning

WARNING!!!
The pot support used for this stove could be VERY DANGEROUS when the pot is removed. Falling on the support could cause major damage. Always remove the support or turn upside down when not cooking.

Information on this site is provided for educational purposes only.

Neither the webmaster nor anyone else whose information may be included on, or linked to, this web site can attest to or endorse the safety of using any techniques, equipment, supplies or services evaluated or referred to therein. Any endorsement or recommendation is limited solely to the evaluator's opinion about their effectiveness when used for their intended purpose in accordance with safe operating procedures, and if available, in accordance with any instructions provided by the inventor or manufacturer. Some survival and outdoors equipment and supplies are inherently unsafe and can injure, maim or kill even when used appropriately.

Endorsement or recommendation of any equipment, supplies, services or techniques does not constitute a guaranty or warranty the equipment, supplies, services or techniques will function when needed.

In daylight you may not be able to see a flame or hear an audible sound from an alcohol stove. A windscreen wrapped partially around the stove may aid in seeing a flame more easily.

DO NOT OVERFILL STOVE. A space above the fuel inside stove is necessary for proper operation and overfilled liquid fuel may be ejected instead of alcohol vapor, creating a potentially hazardous fire.

Individuals not trained and experienced in use of tools and techniques mentioned on this page should not attempt creating a stove without supervision by someone with proper experience and training.

Eye protection should be worn whenever flying metal is possible (such as whenever a drill, hammer or knife is used).

Lighting of stoves should be attempted in a area not prone to fire.

Use of gasoline, or any other petroleum products in these stoves may result in severe burns and/or death.

Nike Patents Marty McFly’s Self-Lacing Sneaker

Wired

By Charlie Sorrel

August 26, 2010

8:41 am

Remember the McFly 2015s, the Official Shoes of Gadget Lab? They were a fairly faithful rendition of Marty McFly’s amazing self-lacing sneakers from Back to the Future 2, forced to the market by the tireless work of the Maloof brothers who spent years badgering Nike into making them.

They looked great, but lacked the flashing lights and auto-lacing functions of the “real” thing. Now, Nike has actually patented a self-lacing sneaker. This, you are no doubt just realizing, is completely frickin’ amazing: It’s entirely possibly that these shoes could actually be in stores in the year 2015, just like in the movie. This would be a weird, time-warping paradox so perfectly mimicking those in the Back to the Future movies that the world might possibly end.

That Nike has filed a patent for these things is mind-bending enough, but pretty much everything has made it in. The shoes will of course fasten themselves, but there are also LEDs a-glowing and a detailed breakdown of the batteries, circuits and control-systems. There is even a charging stand.

One problem Nike might have to face, though, is the existence of prior-art. Not only did the sneakers already show up in the movie, but just last month we saw that an enterprising hacker had made his own self-lacing shoes.

Wednesday, August 25, 2010

HOW TO – Take great photos of your projects

adafruit

The Adafruit Photo Tutorial by Johngineer

This tutorial by John De Cristofaro (johngineer) aims to teach you how to take photos of your hacks and projects for sharing on the web, and perhaps even in print. It focuses on smaller items, less than 6”x6”x6” in size. Bigger projects present their own unique problems that are beyond the scope of this article. However, you can always “scale up” the methods presented here to take pictures of larger subjects, at least to a point.

I’ve divided it into two parts: The first part details how to build a small, inexpensive cyclorama (shooting platform) and the second covers setting up the lights and taking the photos. It assumes you are starting with little more than a camera and a subject to take pictures of. I’ve tried to address a number of questions I’ve received from folks regarding things that are unique to photographing electronics. These include how to photograph lit LEDs and how to make the stamped text on IC packages appear clearly in photos without being washed out.

I’m going to introduce two lighting setups. The first one uses two light sources, and the second one uses one light source and reflectors. The two-light setup is simple, and is good for things like documenting your project as you build it, time-lapse assembly stuff, and general documentation. The one-light setup is more complicated, but also more creative, and is useful for taking final project photos. It also cures baldness, makes you more attractive, and builds self-esteem. Awesome!

I will not be discussing shooting tents in this article. These are already well-documented and ubiquitous all over the web, and in my opinion they don’t teach you a great deal about creative lighting. That isn’t to say they aren’t useful, or produce bad results. They have their place, and for many things they do work amazingly well. That said, the main goal of this article to provide the reader with a basic photo skillset, and I think a shooting tent just hands you the solution instead of teaching you how to solve the problem.

Ok, now that that we’ve gotten the philosophical stuff out of the way, let’s get to work!

What You’ll Need

The cyclorama is a separate project, and has it’s own list of ingredients. However you will need the following items to take pictures regardless of whether you build the cyclorama or not.

Camera — A digital point-and-shoot is fine, as long as you can turn the flash off and it has a macro (close-up) mode. An SLR camera is better, but not necessary. A film camera is fine too, if that’s all you have, though shooting on film may cause some color balance problems if you use incandescent lights. I am using a Canon PowerShot G5. The Canon “G” series provides a great deal of control and older models can be had cheap on eBay. Note: the G7 does not support RAW image capture, but all the rest do.

Lights — You need two, and it’s best if they are identical. You can use work lights from the hardware store if you have to, but I recommended investing in “professional” photo lights from a photo supplier (see list at the end of this document). Often these come up pretty cheap on auction sites or at photo flea markets (~$25, as of mid-2010), and they are a good investment if you plan to use them regularly. If you’re going the work light route you should get the ones marked for 300W lamps. These have a heavy-duty cord and ceramic socket. You should not attempt to use the cheaper low-wattage lamps with a higher rated bulb — even if the cord can handle the current, the plastic base probably won’t be able to handle the heat of the bulbs.

Light Bulbs — In photo and theater-lighting speak these are simply called “lamps”. You should get proper photoflood lamps from a photo supplier, rather than using the 300W lamps from the hardware store. Two common types are ECA (250W) and ECT (500W) — both of these burn at a color temperature of 3200 Kelvin, which is the standard color of photographic tungsten lights. Some people like to use daylight-balanced CFL lamps, but there is a tradeoff. The lights don’t generate as much heat, but their color rendition is poor compared to tungsten lamps. For any of the science-minded who may dispute this, I suggest you look at the spectral output of both: CFLs are a pretty much a picket fence, while incandescents are mostly continuous (though admittedly biased toward IR). The high-powered fusion of the sun puts out a mostly continuous spectrum, overlayed with Fraunhofer spikes, and this is what our eyes (and our camera sensors) are designed for. Gaps in the output spectrum of CFLs cause some colors to be rendered unnaturally, so it’s better to use a continuous-spectrum source.

Tripod — You can work without one if you must, but it is strongly recommended that you use one for critical shots. It helps ensure your photos are consistent and without blur. The heavier the tripod, the better — the greater mass helps dampen vibrations.

Physical Space — You need some space to take your photos, as well as a sturdy table on which to set everything up. You also need room around the table to set up your lights and to move around. The cyclorama shown here has a footprint of about 2×2 feet — keep that in mind if you decide to use it.

Part I – Cyclorama

A cyclorama is a surface that provides you with a uniform background. A cyclorama (also called a cyc, rhymes with “bike”) can vary in size from a tabletop (such as this one) to a warehouse (used for cars and other large objects). It’s really nothing more than a concave surface of uniform texture — it’s horizontally flat in the front and curves up to vertical in the background. The one we’re going to build here uses a lightweight frame of PVC pipe and a sheet of poster board, along with a few thin panels of MDF for extra rigidity. It costs about $20 in parts. If you are using a table that sits up against a wall, you can skip the PVC frame and simply tape the poster board to the wall and table in the appropriate shape. However, you may find the PVC frame gives you more flexibility because you can move around it. The added bonus is that it’s a good excuse to use power tools.

Parts List:

12ft of 3/4” Schedule 40 PCV pipe
6 90° elbows (3/4” sch. 40)
2 tee joints (3/4” sch. 40)
2’x4’ panel of 1/4” MDF (or 3/16” hardboard)
1 sheet of white posterboard (22”x28”) — get a few extra if you can.
2 small binder clips

Cut the PVC into seven segments of 18” in length. Cut the remaining pipe into two pieces of 3” each. Follow the photo for assembly instructions. It really doesn’t matter in what order you put the pieces together as long as you square it up when you’re done. You can use pipe cement too if you want, but there’s really no need. If you leave the pieces loose, then you can take it apart later for storage.

Now it’s time to cut the MDF panel. You’re going to cut two pieces, one 16”x24” and the other 20”x24”. Lay the 16” piece across the bottom and lay the 20” piece up against the back as shown.

If you want to, you can secure the back piece to the frame, though you can just lean it against the back. Take the posterboard and install it as shown, shiny side up.

Clip it to the front edge of the MDF with binder clips and form the curve (an arc of about 3” radius). Once you have the curve the way you like it, tape it to the back board with masking tape.

If all went well, your cyclorama should look like the one in the photo. Congratulations!

Part II – Taking Photos

Ok, so you’ve got your cyc all set up (or not) and you’re ready to take some pictures. There’s no trick to it, it’s just a simple trick. In short, it really doesn’t matter what camera you have, because it’s all about lighting. Your control of the light has the biggest impact on the final product. Composition is important too, but if you have good lighting, the right composition tends to become self-evident. Further, good lighting allows you to show all the details in your work with equal clarity.

The most important thing to remember with lighting is control. You need all the control you can get. This first translates, in this case, to working in a darkened room, preferably at night. The only lights you want falling on the subject are the lights you can control. Light coming in through a window can be very beautiful, but you don’t have a whole lot of control over it, so draw the curtains.

Before you set up the lights, you should place your subject in the middle of the scene. If you’re using the cyc, you want to place it about 4-6” back from the front edge, and centered left to right. It helps if your project can stand on its own. If it doesn’t, you can use adhesive puddy (Fun Tak), to help prop it up to the angle you like. Please note that from this point on, I will be referring to the placement of lights and reflectors as being in position around a clock, with the subject at the center.

Two-light Setup

In this first configuration we’re going to use two lights. There’s not much to talk about here — this is a very basic, functional setup that works well with documentation photos — that is, pictures you take of your project as you’re working on it. It doesn’t work so well for shooting “finished” projects, because it produces some confusing shadow patterns that can be distracting. However, for shooting while you work, it’s the best compromise between quality and expediency.

You should have two matching lights, with bulbs of equal output. Some folks like to put diffusion material over the lights. You can do this if you like, as it does soften the shadows a bit. If you do this, remember that the diffuser absorbs some light, so your exposures will be longer. Also, be mindful of the heat produced by the lamps — you don’t want the material to melt. Try to use heat-resistant diffusion gels, such as those sold by Rosco.
For your start position, set both lights at the same height, about 3 feet above the table surface, and pointed at the subject.

Imagine a line connecting the center of the light bulb to the subject, and another line parallel to the front edge of the table that runs through the subject. These two lines should intersect at an angle of about 45 degrees. This is a good starting point, because it eliminates shadows as much as possible. You will still see some shadows, of course, but we’ll take care of those in editing later. Looking at things from overhead, the lights should be at about 4 and 8.

The camera is at 6 o’clock. The distance from the camera to the subject varies depending on what you’re taking pictures of, but 18 inches away is a good starting point. Bear in mind that it is not necessary to fill the frame with the subject, as you can crop it later. In fact, it’s not advisable to be right on top of the subject with your camera, as it makes it more difficult for you to work (directly under the lights), and it can cause focusing problems. Plus, by moving further away you increase your depth of field, helping everything to be in focus.

If you have your lights set up properly, you should be ready to take some photos. The next section provides some details and hints about using the camera.

About the Camera

Before we continue, I’d like to mention some things about the camera. These are given generally, and you may need to consult the camera manual to learn how to make these changes on your particular camera:

Use a tripod.
Flash: Turn it off because you won’t need it. It’s usually controlled by a button with a lightning bolt on it. The screen will display a “no” symbol (as in “no smoking”) with a lightning bolt inside it.
ISO: Set your camera’s ISO (film speed) to the lowest possible setting. This is usually 50, 100, or 200. Avoid using the AUTO setting. Different cameras have different ways of doing this, refer to “ISO” in the manual.
Aperture-priority mode: Put the camera in Aperture-priority mode. For SLRs and advanced point-and-shoots, this is usually accomplished by turning a dial on the top or back of the camera, and is denoted by an “A” or “Av”. For starters, set your aperture to 4.5. Once you get a feeling for how changing the aperture affects the picture, you can change it to suit your tastes. The aperture affects what is called “depth-of-field”, which is the area from nearest to farthest that is in focus. For most picture taking with point-and-shoots, this isn’t much of a concern. However, when you are shooting close-up you need give it some thought. The higher it is (the greater the depth of field) the more of the image will be in focus. For things that are very close up (less than 12 inches), you should set it to maximum. If you still can’t get everything into focus, try moving the camera back a bit and then cropping later in an editing program.
Image quality: Set your camera to the largest image size available, and with the lowest compression setting (i.e. the largest file size) — this is usually called “fine” or “superfine”. If your camera supports RAW output, you can use that. RAW images store the full output of the camera sensor and are more suited to later editing. For the purposes of this tutorial, I’m going to be working with JPGs from the camera. There are plenty of resources available regarding RAW image workflow if you are interested in that.
White balance: Set it to incandescent (aka “tungsten”). This is usually indicated by a little light bulb icon. This sets the color balance of the camera to a color temperature of 3200K, which is the color temp of the light’s we’ll be using. I won’t go in to what color temperature is or how it’s calculated, because it’s a bit involved. Suffice it to say it’s based on one of those ideal theoretical constructs physicists are so fond of.
Focusing mode: For most stuff you can use the camera’s autofocus mode. Manually focusing a point-and-shoot is often more trouble than it is worth. It’s quite easy to do on an SLR, but most modern AF systems work so well that it’s doubtful you’ll be able to improve upon things. That said, there are some things to keep in mind when using Autofocus. AF systems require contrast to focus properly, so pointing the focusing window at a broad expanse of solid color will cause problems. Try moving the object or camera a little to give the camera something “busy” to look at. Flashing LEDs can also seriously throw off an autofocus system. If you see the camera oscillating in and out of focus, and you have flashing LEDs, try moving things around as above, or change the LEDs to a steady pattern. If that doesn’t work, you may have to manually focus the camera.
Macro mode: Many cameras have a “macro” mode, which is engaged by a little button with a flower icon. Macro mode allows the camera to focus on subjects very close up. This mode usually works best when the lens is zoomed all the way out (wide angle), and zooming in past a certain point may actually turn the mode off. If you find that macro mode keeps turning off, this is probably why. However, you might find you prefer moving the camera back and zooming in as opposed to getting in real close. This tends to “flatten” the field of view a bit, whereas getting up close with a wide angle can result in an exaggerated perspective. The other nice thing about zooming in from further back is that you constrain the field of view to an area where you have full control of the light, resulting in a more even lighting in the photo.
Self-timer or Remote: Most cameras have an adjustable self-timer, and some have remote trigger as well. These are both very handy features to have, and you should use them if you have them. The reason is because when you are holding the camera and pressing the button, you introduce some vibration through your arm which can cause the photos to be blurry. By either delaying the shutter until your hand is away, or firing the camera remotely, you can eliminate this problem. On a related note, be sure that the floor isn’t vibrating when you take the picture (i.e. don’t walk around near the tripod), as this can also cause blurry photos.
Use a tripod. This tip is similar to tip #1, except I really mean it this time.

Tips for Taking Pictures

Ok, so now it’s time to take the photos. Assuming you’ve followed the tips above, you should be able to take a picture of your subject. The only thing remaining is to check the exposure. For feedback on this, we need to look at the histogram. The histogram looks sort of like a spectral graph (like in a spectrum analyzer for your stereo), and it shows you how much of each tonal value is in the photo. Most of the time, it resembles a sort of mountain range. The position of the histogram is related to the brightness of the image. If it’s shifted to the left, that means most of the values in the image are dark, and if it’s shifted to the right, it means most of them are lighter. The best place for the histogram to be, in most cases, is in the middle. This means we have an average tonal distribution with some highlights and shadows. See the photos for examples.

If your histogram is shifted far over the right or left, you need to adjust the exposure. Assuming you are in aperture-priority mode, you want to look for the exposure adjustment controls. This is usually indicated by a “+/-” symbol. When you press this button (sometimes you have to hold it down while you make adjustments), you’ll see a scale going from plus to minus in indexed increments. Often, exposures are thrown off by the background. If you’re using the cyclorama, you’re shooting on solid white and so the camera thinks it’s brighter than it really is. To remedy this, you need to set it to more exposure.

You do this by moving the pointer over towards the “+” symbol, usually by about 2 or 3 index points. If you’re shooting on a black (or dark) background, you need to do the opposite.

The histogram is the best indicator of good exposure — don’t go by what the picture looks like on the LCD, because it’s always wrong. ALWAYS. It’s only there to give you a general idea of the composition and focus. Don’t bother using it for anything else.

One-light Setup

No reflectors

The next configuration we’re going to use requires one light and a few reflectors. While this sounds limiting, it’s actually got a lot of flexibility. The natural world is, after all, basically one light (the sun) and a reflector (the sky). The reflectors are the key. Much of the light radiated by a light source is wasted, traveling in directions that contribute nothing to the photo. Reflectors help bounce (and sometimes diffuse) that light back onto the subject, filling in shadows and highlighting critical areas.

There are two reflector types we’ll be using, and they each do different things.

White panel reflector (off to right)

The first is a diffused panel, which is basically a piece of white cardboard or foamcore.

The second is a mirror. We use each of these reflectors for a different purpose, but rather than detail each purpose now, I’ll explain them individually as we introduce them to the set up.

First, the light. Place the light at about 3 feet above the surface of the table. Set it 4 feet away and at the 9 o’clock position (off to your left), and pointed at the subject. Leave enough room to move it ±1ft towards or away from you later.

There’s always the temptation to put the light as close as possible to the table. While this does increase the amount of light, it is very uneven illumination — the gradation from light to dark across the background (and even the subject) can be very noticeable. This is due to the nature of light as electromagnetic radiation, which means it is governed by the inverse square law. I won’t go in to calculations here, but it’s best to remember that the closer the light is to the subject, the higher the contrast between light and shadowed areas. When you move the light away a bit, things tend to “even out” a lot more — it also makes it easier to work because you don’t have a hot, high-wattage incandescent light right in your face.

If you look at the overhead photos, you’ll see where each reflector is placed for this particular setup. Naturally, every subject will require a different placement of the mirrors, and some may not require you to use all three. There’s a lot of trial and error here. Set up your subject in the “pose” you like, light it, and then add and move the reflectors around until you get what you like.

White panel reflector

With the light in position, we’re going to introduce the reflectors. The first reflector is a diffusion panel (sometimes called a white card). 1/4” white foamcore works great for this best because it’s lightweight and rigid, but you can use any sort of white panel. You’re going to prop it up on the right side of the subject, about 12” away. If you’re using the cyc, you can just lean it against the side as in the photo. Watch the shadows cast by the subject darken and lighten as you remove and replace it in position. Our goal with the reflectors is to lower the contrast ratio, which is the proportion of the lightest part of the scene to the darkest part. Digital cameras have problems resolving higher contrast scenes, and so we need to bring the contrast down to a level where it can record everything. If you move the reflector away from the subject, the contrast increases, while moving it closer causes it to decrease.

White panel + 1 mirror

White panel + 2 mirrors

White panel + 3 mirrors

Next we’ll introduce the mirrors. I have three mirrors, one big one (5”) and two small ones (3”). These are the kind you can get at a discount store — make-up mirrors with a collapsible handle that allows you to stand them up on a table. They usually have mirrors on both sides — one is flat and the other is concave. The small ones cost about $3. Buy them in black if you can.

Where the mirrors go in your setup depends on the subject. You want to look for spots on the subject that look particularly dark, and use the mirrors to fill them in. Start with the largest mirror. Think of this as starting with a broad brush and working your way down to a fine tip for the details.

Looking at the photo with just the white panel, we see that the lower-right side of the subject is still much too dark. We need a significant amount of fill here, so we use the large 5” mirror to bounce some light back onto our subject. (photo & overhead #3).

Now we’ve lightened up the lower right a bit, but the area around the chip is still too dark, so we add another reflector off to the left of the camera to throw some light in that area. Note that this mirror is set at a rather shallow angle, in order to catch the light from the source and reflect it to where we need it. (photo & overhead #4)

I shot this on my workbench with one light off to the left, and two reflectors (mirrors) filling some of the shadows.

Finally, we still need some light to the right of the microcontroller, around LED7. So we put the last small mirror to the left of the big one and lighten this area up a bit (photo & overhead #5). Then we take the photo, and we’re done!

Just one note: like anything worthwhile, it takes a while to get good at doing this. You need to practice and change things up now and then in order to learn what looks good and what doesn’t. And you don’t have to stick to the cyclorama as a background either — you can use any tabletop/background, provided you have the room to move the lights and reflectors around. Take a look at the last photo in this section. I did that one on my workbench with one light and two reflectors. I actually like it more than most cyc shots, because it has context. So don’t be afraid to play around and find what you like.

Tips for LEDs

One thing you’ll notice in the pictures above is that the LEDs are rather well balanced with the rest of the picture. One of the advantages of using the lighting method presented here is that there is plenty of illumination available to light up the rest of the PCB and components, allowing them to “match” the brightness of the lit LEDs. There’s an added advantage in the above example because the LEDs on the Game of Life board are diffused, which cuts down on their output a bit. That said, every LED is different — some are diffused, some are clear, and they have different levels of output. If you’re trying to shoot a project and the LEDs are just too bright, there’s a few things you can try:

Try using brighter bulbs in your light sources. If you’re using 250W bulbs, for example, try switching to 500W.
Move the lights a little bit closer to increase the brightness of the scene. This will have an affect on the shadows and contrast too, though, so don’t be too extreme in your adjustments.
Add another light. It might surprise you to learn that two lights is brighter than one light!
Reprogram the circuit to put out a lower LED level. This only works if you have PWM control over the LEDs, but it works quite well.

Jim's Nut & Bolt Bucket