Introduction: Disposable Camera Ring Flash

Picture of Disposable Camera Ring Flash

Build a disposable camera ring flash. Disposable cameras are discarded after the film has been removed. Photo labs often have boxes of them under the counter, waiting to be recycled. If you ask nicely, you can often get more than enough to experiment with. Try to get at least six for this project, all of the same type.

Step 1: Build It

Picture of Build It

10" Cookie tin
6" Metal dog bowl (Dollar Store)
Disposable cameras
Radio Shack AA battery pack (with built in switch)
RD616 wireless flash trigger ($20 Ebay - search: "flash trigger 16 channel wireless")
Surgical tubing
Old tripod plate
Broken door cloths hanger
3.5mm phone jack
Packing Tape

Carl Vogt's $5 Photo Slave:
SCR 400 Volts 4 Amps (NTE5457 or Phillips C106D)
1 meg ohm 1/4 watt resistor
.05uF 400 Volt capacitor
Perf board
Solar cell from a dollar store calculator (WARNING: Dollar stores often sell calculators with fake solar cells)

Nibbler (Radio Shack)
Punch (or nail)
Soldering iron
Solder sucker
Wire stripper
Hot glue gun
Alligator clips

Step 2: Open It Up

Picture of Open It Up

WARNING: A fully charged capacitor can give a good shock or burn. Do not touch the circuit board or the battery holder. Use the end of the large capacitor as a handle when working on the flash. Remove the battery from the bottom of the camera. Use a small screwdriver to cut any paper sealing the camera and to pry it open.

Short out the capacitor with the tip of a screw driver by touching both leads of the capacitor at the same time. Once the capacitor is discharged, there is less risk of being shocked. WEAR SAFETY GLASSES when shorting out the capacitor. There may be sparks. Getting hot solder in the eye is a life changing experience.

Step 3: Flashes

Picture of Flashes

Replace the flash trigger mechanism with wires. Use a solder sucker to remove the solder then push out the metal lever and knob with the tip of a hot soldering iron. Solder on a generous length of wire to each contact. They can be cut to size later.

There is also a simple pressure switch to turn on the flash. Push the metal prong with a nail until it is touching the board, and then solder it to both contact pads. Now the flash will always be on.

Step 4: Testing

Picture of Testing

Often some of the flashes will be damaged. Test all of them with the RD616 wireless trigger using alligator clips and mark the ones that fire reliably. Refer to the wiring diagram for the proper connections. The RD616 is used instead of directly connecting the flash to the camera and risking damage from high voltage.

Step 5: Slave

Picture of Slave

Build Carl Vogt's slave using perf board and then test it with each of the flashes. If you are lucky all three flashes will run off of one slave, otherwise you will have to build several slaves. A soldered circuit is the best, so what doesn't work with alligator clips, might work when the flashes are installed.

Step 6: Cookie Tin

Picture of Cookie Tin

Mark a 3 1/2" circle on the bottom of the metal dog bowl. Punch or drill a hole in the bowl and then use the nibbler to cut out the circle. Drill 4 bolt holes around the edge of the circle.
Place the bowl in the middle of the cookie tin. Mark all holes and drill or nibble to remove metal. Use a file to dull sharp edges.

I used an old plastic camera plate attached to a broken door cloth hanger to mount the camera, but any angle bracket will do. Drill holes and attach. Drill and install the 3.5 mm phone plug.

Cover bottom of cookie tin with several layers of clear packing tape to insulate the metal from touching the flash circuit boards.

Step 7: AA Battery Pack

Picture of AA Battery Pack

Rewire the AA battery pack so the batteries are in parallel, not in series. This will keep the voltage the same (1.5 volts) but increase the amps. Use a needle nose pliers, screw driver and a soldering gun to remove metal contact plates (spring and nipples). Cut the plates with tin snips and place all the springs on one side of the battery pack, and all the nipples on the other. Take a bare wire and solder all the nipple plates together. Then solder all the spring plates together with another wire. Attach the red wire to a nibble plate and the black wire to the switch. The switch in turn connects to a spring plate. Install batteries and test the voltage with a multimeter.

Drill a hole through the lid side of the battery pack and bolt it to one side of the cookie tin. Run the battery wires through another hole into the cookie tin.

Step 8: Wiring

Picture of Wiring

Solder wires from the battery clips of the most reliable flash to the external battery case. This flash will be the trigger flash. Hot glue the flash into position in cookie tin. Solder the trigger wires from the flash to the phone jack. Plug in the RD616 wireless trigger into the jack and test. Hot glue velcro to the outside of the cookie tin to hold the RD616 in place.

Hot glue the slave near the trigger flash. Solder the second flash to the slave and the battery pack and test. Do the same with the third and fourth flash.

Step 9: Finish

Picture of Finish

When everything is working, bolt on the dog dish and camera mount. Split one side of the rubber tubing and cover the edges of the inner hole to protect the camera lens. At 8 feet you should get about F5.6@60 100 ASA. The slave will not work in bright sunlight, but it's suitable for indoor use.

Additional modifications could be adding 4 more flashes or making a wax paper diffuser for the front of the ring. Use any leftover flashes to build a peanut butter jar strobe, a simple disposable camera slave.

Some people have built peanut butter jar slave strobes and have had trouble getting them to sync with their camera's flash. This maybe because the on camera flash is firing a distance measuring pre-flash (infrared) which is triggering the slave.

Possible solutions:
1. Set the flash to a totally manual setting, if possible, so there is no infrared pre-flash.
2. Make sure the camera's shutter speed is slow enough to sync. (60th)
3. Use an older style flash that doesn't pre-flash.
4. Construct a trigger flash with a RD616, so an on camera flash is not necessary.


etw (author)2011-07-07

Interesting project. Currently playing with disposable flashes myself. The only thing I had trouble with is the Carl Vogt trigger. That only seems to work when I leave out the capacitor.

The photocel should be sufficient as it seems to come from the same type of calculator that can be seen on Carl Vogt's project ;-)

Divet (author)etw2011-07-09

Test the solar cell with a multimeter to see if it produces voltage when in the sun. Try also switching the solar cell leads to the capacitor or swapping out the capacitor with another. I used a cheap polycarbonate capacitor, but just about anything will do.

etw (author)Divet2011-07-09

Thanks for yr advice. Yes I did test it and it does produce about 4 volts inside for a well lit window. I have tried several capacitors, but apparently the only value that works for me is 0 Farad and even then it is not very sensitive. (no sensitivity for bounce flash and I really need to aim at the cell).

How much Volt should it produce to work properly?

Divet (author)etw2011-07-14

The solar cell is producing more than enough voltage. Make sure the polarity of the cell is correct, positive to capacitor. If you have already tried swapping out the capacitor and resistor, then it most likely is a SCR failure.

etw (author)Divet2011-07-14

Thanks, yes polarity is correct. The SCR is working (if no capacitor). Anyway I will try with another SCR. Thanks for the advice

etw (author)etw2011-07-16

Low and behold, a different SCR seems to have done the trick. Odd, as the first one I tried was fresh from the shop.

I must honestly say that I did not expect this, but as the circuit apparently is successfully built by many people and the cell, resistor and capacitor were not the problem, well, then it must be the scr ;-)
Strange enough I have used it (after the slave did not work) in another project where it performs fine. Perhaps less critical

Thanks for your valuable advice

etw (author)etw2011-07-16

Like to add that also the sensitivity is great, reacts to bounced flash at least 4 meters away, even when the voltaic cell is pointing the other way.

I am impressed

rfowler643 (author)2010-04-26

I played on your idea Divet and made a studio strobe.  It consists of your four disposible camera flashes, a popcorn bowl, a steamer meal bowl, a Carl Vogt trigger, a homemade light /sound flash trigger, PVC pipe and a power pack.

Divet (author)rfowler6432010-04-26

Pretty cool. Are you using batteries or an AC adaptor to power it?

rfowler643 (author)Divet2010-04-27

I power it by batteries but I also have a plug in to run it off a plug in power pack as well. 

Thanks for your idea. 

rfowler643 (author)2010-04-09
What an absolutely outstanding project.  I especially like the peanut butter jar slave flash.  I completed one last night and am working on a second one now.  It is very convenient to position these flash units wherever I need additional light.  
I had to experiment with an old Canon speedlight on my XSi to get the right flash sequencing to overcome a premature firing of the flash jar. It would be nice to control the timing to make it easier to use with the camera factory flash but I am very happy with it.  
The trigger circuit using the calculator photocell is brilliant!  So cheap and works so well. Thanks again for the projects.  They are great!
I am going to make a flash unit and house it in a plastic steamer meal dish that is made of milky white plastic. This container should act as a nice light diffuser when combined with the disposable flash units.
Thanks again.
Divet (author)rfowler6432010-04-10

What speedlight and settings did you use to get it to sync?

rfowler643 (author)Divet2010-04-20

I was able to use the flash jar with the camera in manual and the speedlite set to ASA25 f2.8.

I completed a 4 flash unit I will be using for a studio flash.  I combined all the triggers to a common connection but the flash trigger I used does not trigger all the flash units.  If I manually short the trigger wire, all four flashes fire.

I am going to try adding one or more Carl Vogt triggers to see if that helps.  I can add a picture or two as soon as I tidy up the finished product. 

Thanks again for the amazing project.

rfowler643 (author)2010-04-11

I am using a Canon EOS XSi DSLR.  The speedlite I use is is connected to the XS1 hot shoe and is an old speedlite from my 35 mm Canon SLR.  I was able to use the flash jar with the camera in manual and the speedlite set to ASA25 f2.8.  Otherwise it seems the flash jar doesn't like to syc with the camera even when using the speedlite.

I need to play around with the camera, the speedlite and the flash jar more.  I made a second jar now.  I have the orientation of the flash to the photocell set up in such a way that one jar is for right hand flash and the other is left hand flash.

rfowler643 (author)2010-04-10

This is a great project.  I also noticed there was a posting for a peanut butter jar slave flash.  Is this by the same author?I made two of the jar flashes and am very pleased with the performance and portability.  Thanks to that inventor as well.

guydie5 (author)2009-06-30

i asked for some used cameras at cvs and they refused me

peterrabid9 (author)guydie52009-10-27

Try Walgreens, or wait until someone else is behind the counter :-D  Seriously, when I worked at Walmart, we would supposedly get $.50 for ever camera we sent in.  That added up to alot at the end of film's popularity, but after that, kinda iffy.  Worse case, pick up some cheap junk cameras at the Dollar General, and use them up for fun.  


TheBestJohn (author)2009-02-24

All I could find at my components store was a 0.10 uF 400V cap (They never have what I need)... will that do?

Divet (author)TheBestJohn2009-02-25

It's not going to hurt to try. Cheap capacitors can be 20 percent or more off value. If it doesn't work, try putting two .10uF capacitors in series to make .05uF.

TheBestJohn (author)Divet2009-02-25

bah... neither way worked... guess I'm going to have to hunt down a proper cap... I used metal polyester... could that be it... is it supposed to be ceramic?

Divet (author)TheBestJohn2009-02-26

I used polycarbonate, but polyester should work.

uMicro (author)2008-11-20

Divet, Can you use a contact relay to trigger of the unit? is there a timing issue with the relays?.. i have also seen to build a Safety flash unit which (quote): The voltage is limited to safe levels and the SCR fires the flash. The circuit is effectively a switch in series. I'm building a much bigger version with 16 flash heads, and a variable capacitor that doesn't rely on any slave units.. I have currently completed one prototype that works with a simple switch that triggers 4 units and currently trying to implement the relay system but i don't know if there is a timing issue. Can you get back to me on of a relay can work or not..

Divet (author)uMicro2008-11-20

A relay can trigger a flash, but people have reported timing problems.

A different schematic to limit voltage that might be interesting.

If you come up with something, please post your results.

Derin (author)2008-06-17

you could also use 380V mains for the photoflash

Derin (author)Derin2008-06-21

photoflash bulb , that is

LinuxH4x0r (author)Derin2008-09-25

would it work on only 120 or on 240?

Derin (author)LinuxH4x0r2008-09-25

380V three phase delta config. aka phase to phase, 120 or 240 wont cut it and you need a brief voltage of about 1kv on the trigger plate for the bulb to do its thing

LinuxH4x0r (author)Derin2008-09-25

darn. I didn't think so

uMicro (author)LinuxH4x0r2008-11-19

The flash work on 1.5 volts, the heads are small so they don't require high voltage. if you want to use 3 phase power, you have to pull the board completely.. and design another.. Phase power is more for the xenon flash bulbs, cause its more efficient. The problem here is the current supplied. that's why the power box is in parallel instead of series. To boost the amps.

optix (author)2008-10-23

I would recommend using a resistor to discharge the capacitor. It's much safer than the screwdriver method, even though it's not as fast. My favorite method is a 40W 120V light bulb, with a 10 Ohm 10 Watt wound capacitor in parallel, all attached via test-leads. Then you can visually see how close to drained the capacitor has become, before touching it. I've used this method on many capacitors, some very large (think mega Farad).

uMicro (author)optix2008-11-19

discharging a small capacitor is quite safe.. if as you said discharging a much larger capacitor is much safer.. for this project just be sure to keep eyes away from the spark.. most of the time if the flash doesn't fire the arc won't be that big.

LaxLuvr (author)2008-02-24


technodude92 (author)LaxLuvr2008-02-24

its better if you lick your thumb first. :P

Its even better if you lick the charged caps, i mean, come on, its only NEAR lethal anyways.... why not? WARNING DO NOT LICK CHARGED CAPS >.> IT IS JUST A JOKE.

Myrddin (author)LaxLuvr2008-03-01

Ding-a-ling! YOU ALWAYS WATCH WHERE YOU PUT YOUR FINGERS!! Charged caps are not a toy lucky you kill your fool self! Now stay after class and write on the board "I will ALWAYS discharge Caps in any circuit." Remove all batterys and flash the unit before u do anything. If you were a cat you'd only have 8 lives left...

twenglish1 (author)LaxLuvr2008-02-24

you touched the capacitor didn't you

reesea17 (author)2008-08-28

what type of capacitor is that?

peterrabid9 (author)2008-06-24

Hey, what happens if you put the batteries in line? Does providing more voltage give a faster recycle time, or does it fry something in the circuits? Still a good Instructable, I'm going to build some things using this puppy.

Divet (author)peterrabid92008-06-29

Putting the batteries in line would increase the voltage, but you would run the risk of blowing components. Also the amps would be low, the same as one battery by itself. If you have multiple flashes connected to the same power source, you need enough amps to run them all.

blodefood (author)2008-04-21

Disposable? Why not recyclable?

Derin (author)blodefood2008-06-21

it is recyclable it says disposable because it is used till the storage is full then it gets recycled after retrieving images at a photo shop

ezfoxz (author)2008-03-10

We did this and dared my friend tommy to piss on the board. The result was bad he was rolling on the ground screaming in pain pissed all over his self. Me and my friend Tod laughed our asses off. Well until he got up. Tommy was realy pissed off and came after us with a 2x4 he was trying to kill us over this what the hell. luckily I was faster than my other friend Todd. I triped him and thats the last I seen of them Im hoppeing we can just put this behind us and be friends agin.

Derin (author)ezfoxz2008-04-01

wat is a 2x4

Estwald (author)Derin2008-04-03

A piece of wood 2 inches tall by 4 inches wide. Standard lengths are 6 feet, 8 feet and 12 feet. Also note, the 2 by 4 inches is rough size, planing and finishing reduces the final dimension.

Derin (author)Estwald2008-05-08

here we have 5x10 as a standard

Derin (author)Derin2008-06-21

a 5x10 is the same size as a 2x4 because the 5x10 is metric while the 2x4 uses inches.

dannye90 (author)ezfoxz2008-03-23


afiqrostam (author)2008-05-28

is it posible to test the flash without using the rd616? i mean direct input.

Divet (author)afiqrostam2008-05-29

Testing the flash by directly attaching it to a camera with a pc connector is not recommended. The flash voltage is very high and you would risk damaging a digital camera. I would only attempt this using a safe sync adaptor that would lower the voltage or with a older camera that does not contain any electronics.

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