DISPOSABLE CAMERA FLASH CONTROL

[FireGod]

I wanted to use strobes in my display but the cost is quite high even for curtain strobes. I bought a load of disposable flash tubes and went to build a power supply/trigger but the cost was way too high for the componets.

I pulled the strobe out of a disposable camera and found a way to trigger it. With the circuit below, I can trigger it from Vixen several times a second.

I have found these cameras for as low as $1.95 with free shipping. Resell the film and batteries (AA size) and make some of the money back. I am also going to check and see if I can purchase used cameras.

I am planning to purchase a bunch of these cameras, tear out the strobes, and build a honker 300 VDC power supply.

The circuit below is just for one strobe so each strobe would need an 800 ohm resistor (or higher value for longer charge times or lower value for shorter charge times).

Steps:
*Remove the strobe from the disposable camera
*Toss the battery
*Connect SW2 to the SCR
*Connect the SCR to triac driver (in your SSR)
*Connect the 300 VDC power supply (with charge limiting resistor) across the large capacitor
*Trigger it with Vixen

The 800 ohm resistor heats up if you flash frequently.

Here is what it looks like after you remove it from the camers (without the battery).
http://web.olpdsl.net/firegod/DIY/STROBE/BARE_BOARD.jpg

http://web.olpdsl.net/firegod/DIY/STROBE/SCHEMATIC.JPG

[Matt]

Cool!

What kind of camera? Is it the disposable type you can get at Walgreens or something else?

How long do the flash bulbs last? Do they blow out after so many flashes?

-Matt

[FireGod]

I am sure any disposable camera would work. They all look about the same and even the button for charging the capacitor is in the same place. Go to Walgreens and see if they will sell you the old ones that have been turned in. You only want the circuit board. The case might make a nice enclosure with some silicone sealer or latex caulking.

I have not tested how many flashes it will go but that is on the list.

I would search eBay for "disposable camera" and there are lots of hits. They sell them in lots of 10, 15, 20, and 25. The shipping is quite high but the price is about as good as it gets.

These guys (http://www.phototechservice.com/disposablecameras.htm) might sell them at a low price.

[Zane]

The shipping is quite high but the price is about as good as it gets.

hmm not to be wise but i went to the site and right at the top it said free shipping :lol:

[Macrosill]

I believe the shipping statement was pointed towards the Ebay sellers.

[Zane]

I just realized that they where based out of my city :lol: maybe i could pick them up somewhere in town and send them to people.

[FireGod]

I used a 120/220 volt transformer for testing but when I build a LARGE power supply, I'll just pull 220VAC directly from my breaker box.

A fuse, few big diodes for a full wave rectifier, and a couple of huge 450volt capacitors (from eBay) should do the trick.

Edit: I'll probably do a two stage charging circuit. One slow one with a limiting resistor to get the caps up to a reasonable voltage and a second one without current limitng to maintain the voltage.

[Matt]

Let us know how it goes with those monster diodes and caps!

-Matt

[buck]

Try these there cheap.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G15800

[FireGod]

If I buy just the bare boards like Buck found, any ideas for weather proofing?

My first thought was to mount the SCR and charge limiting resistor on the board, solder the four wire leads to the board, then get a gallon of fiberglass resin and hardener from AutoZone (or whereever) and coat the entire thing except the lens. Either paint it on, dip it, make a cheap mold, or just pour it over both sides of the board.

Remember, the flash is started with a 4000 volt pulse and the capacitor is at 300 volts so it is importaint that it stay dry.

Thoughts?

[Josh]

how about doing your idea, but using the tool dip they sell? its more rubber and would be easier to apply

[FireGod]

I will try something soon. I just bought 100 of the boards from the Electronic Goldmine so I am committed (and my wife thinks I should be committed).

[Ronp]

Why not go with the ulta brite leds for strobes 8)
conected to the 595 directly no relays then you can time them with vixen.

[FireGod]

I don't think it would have the same blinding flash of a 5 joule plasma arc.

[Ronp]

http://media.putfile.com/Strobe-67
yes its 1 led

[FireGod]

If it were a camera strobe you would not need to turn off the lights. The high output LEDs I have found are for flashlights (torch) and such.

[FireGod]

I bought 305,000 uF of 350VAC capacitors (5 x 6100uF) for the power supply. The camera boards are on the way.

[jcoll549]

Do you have a part number of what you used?

Jeff C

[buck]

FireGod,
Do you plan on using your HV power supply to charge the onboard caps or are you going to power the strobe tube directly ?
Steve

[FireGod]

Do you have a part number of what you used?

Jeff C
I bought all five of them on eBay for $25.00 ($5.00 each). If you bought them from Mouser they would cost $125.00 each (a total of $625.00). I don't have them yet, they are on the way along with a 40 amp bridge rectifier.

I am also getting ten 10 watt 1K resistors. I plan to put 5 in series with two parallel paths for the slow charging circuit. I bought a 40 amp contactor also on eBay for $15 delivered. You can not just plug the capaitors into the 220VAC bridge, it will blow the circuit breaker so you have to get them charged first before bypassing the charge limiting resistors.

Here is what I have in mind:

http://web.olpdsl.net/firegod/DIY/STROBE/Charg.GIF

I will be using the 300VDC power supply to charge the on board cap. I am using an 820 ohm resistor between the 300VDC power suppy and the on board cap to limit the charge rate. Each on board cap will have an 820 ohm resistor. You also have to do this or the strobe would drain the power supply while melting itself down.

If you play around with this stuff, be very very careful. These caps are deadly once they are charged.

Edit: Schematic was revised to show the "as-built" condition 6/28/07

[FireGod]

Did an 8 channel test tonight. The power supply is simply an 8 Amp fullwave rectifier bridge off of a 220VAC transformer, no storage capacitors.

The camera lens causes the flash to appear low on the screen. The strobes are actually at the top of the screen (the eight black blobs).

[jcoll549]

I was looking more for the super bright LEd that was used. 300 V is more than I really want to play with.

Jeff C

[FireGod]

I was looking more for the super bright LEd that was used. 300 V is more than I really want to play with.

Jeff C

I think a flashlight (torch) LED is all you will find. I did run across a "flash" LED that looked like an array of these LEDs (12 to 18 bright LEDs).

I tried to incoporate a Radio Shack strobe into my display last year but it got lost and was too dim compared to the rest of the lights. If you use any strobe or LED you should place them in a dark area so they will be seen.

I assume that if I set up 100 of these strobes it will be noticed.

Again, there is nothing that will compair against a plasma arc flash (strobe).

[FireGod]

Sorry, this is long winded but this is almost a "How to".

I have been working on a few methods to waterproof the strobe units. I found that some of the disposable camera flash units did not have lenses therefore exposing the reflector that conducts the very low power 4000 volt pulse to get the plasma arc started in the strobe bulb. I have discarded the units without lenses.

The Units I purchased from The Electronic Goldmine had lenses but I have run across a couple that did not work so I test each one using the 1.5 volt AA battery before beginning the modification.

After testing the unit with a battery, the first step is to discharge the capacitor by flashing the unit and then shorting across the capacitor. Then cut off all the unneeded hardware (battery holder, charging switch SW1, and trigger leads noting where the trigger leads are connected). Then carefully bend the capacitor leads so the capacitor is close to the board if required.

I am using 6 conductor 24 gauge telephone wire from Lowe's. I solder two wires to the negative side of the camera flash unit capacitor and connect them to the negative side of the 300 vdc power supply (green and yellow).

I solder two wires to the positive side of the camera flash unit capacitor (white and blue). On the other end of the white and blue wires I attach a 2 watt 820 ohm resistor and connect the resistor to the positive side of the 300VDC power supply. I first tried to put the resistor on the flash unit but if you flash many times in a few seconds the resistor can get hot so it needs to be in open air and not thermally insulated.

I solder the red and black wires to the trigger connections on the board(SW2). It is easier than stripping the wires and soldering to the wires and insulating the connections.

I then again test the unit for proper operation by turning on the 300 VDC power supply and shorting the red and black wires together. My 300vdc power supply is simply a diode bridge connected to 220VAC transformer. After testing the unit, I turn off the power, flash the unit, and short across the capacitor to avoid shocking myself.

Waterproofing:
I tried several different methods:
Fiberglass resin - I poured it over the unit until it started to gel. It looked good but was not perfect and the 300 vdc power shorted out. I tried a couple of times but it was not easy or successful. I did not try to make a mold and "pot" it.

Plasti Dip (for tool handles) - I had to dip the unit several times with 30 minutes between dips. I had trouble covering all the voids and crevices. Now I have pockets of undried Plasti Dip and it still has not dried. This method was quite time consuming but still might work.

Silicone sealant - Masked off the lens, which was not really required since you can control where the silicone goes. I grabbed a tube of silicone and smeared it real good until I saw no parts other than the lens. I allowed the silicone to dry overnight. This worked perfectly and was fast and easy. Large cauking tubes of silicone can be found at Lowe's, Home Depot, or the hardware store. Latex caulking might even work.

The video is of a unit flashing underwater.

[FireGod]

I got the power supply up and running.

[Wayne J]

OMG!
http://i4.photobucket.com/albums/y122/MERC460/smileys/jawdrop.gif

Looks really nice,..... scary...but nice.

[wjohn]

I think I saw an earlier version in Dr Frank-n-furter's Lab on Rocky Horror Picture Show ;-)

[klanger]

I think i saw that in "Die hard"

Don't cut the red wire, or was it the black, hmmmm

[ErnieHorning]

Let's you get that one on an airplane. :lol:

[AI]

Firegod; Nice work so far. I tryed high power LEDs and over drived them but still not the same as a flash bulb. Unless you use 25 or so.
One warning about the silicone glue it will react with the copper and corrode. The ones you made may not last to long. You may be better off with a conformel coating that thay use on PC boardes if you can find it. AI

[FireGod]

A bit of an update:
The SCR must be within 6 feet of the strobe unit to work. If there is more wire than 6 feet, it will not trigger every time.

I also added a fuse to the charging circuit on each strobe to prevent a meltdown.

[NogginBoink]

FireGod,

Why not build a high current 1.5V power supply, and use the charging circuit already on the camera board?

[FireGod]

The on board circuit has a low current/high voltage transformer to charge the capacitor. It only charges at one rate....slow.

I am able to get at least one flash per second with the external 330VDC power supply. The flash rate is only limited by the 820 ohm charge limiting resistor.

If one flash every 10 seconds is OK with you then a large 1.5VDC power supply would be the way to go.

[docjon]

Hi FireGod,

I know this thread s quite old but i was wondering if you had any pictures of the final design/layout, or if you had any detailed documention of the design.

Thanks

[FireGod]

Hi FireGod,

I know this thread s quite old but i was wondering if you had any pictures of the final design/layout, or if you had any detailed documention of the design.

Thanks

I am still having trouble triggering the strobes. The SCR does not trigger the strobe every time where a mechanical switch will do it.

My first batch of eight worked perfectly but the second batch of 32 did not. I don't knnow what I did differently on the second batch. SCR too slow switching? I still don't know.

[docjon]

Is this going to be something you will try and solve?

[FireGod]

I have been working on this again. I have found that cheap units don't work. Those from the Electronic Goldmine don't work well. I also tried a Select Brand from Walgreens and it did not work either. I have 6 Polaroid units that work and I bought a Kodak disposable unit and it works also.

I'm not sure what the difference is between the units. There is a small capacitor that charges and when the unit triggers, this cap discharges through a 4000 volt transformer which gets the plasma stream inside the strobe tube going. This small cap may be too small, the transformer may be inferior, the construction of the strobe tube may be poor, I just don't know.

I do know if I buy name brand disposable flash units (new) they work no matter how long the lead wire. I have one lead wire that is about 15 feet and it works well.

I am using SCR's to trigger the strobe but a triac might work. For that matter a triac driver might work, I have not tried either one yet. I do know what ever is used it need to be very fast.

[jmksparks]

Yes same problem here, what ever is placed across sw triggers flash and prevents charging. Even tried germanium based components, ( less leakage ) I have six at the moment powered from the 5volt cat line down to 11/2v as I have said before through an Lm317 IN REVERSE. And 5v relays for the switch but that can add up. 20 strobes at $4 relay whooo. My turn round time between flash is about 3seconds, thats good enough for me, I will only be using them for a final flash.

[FireGod]

I have a 110vac/220vac transformer and I use a full wave rectifier to charge the capaictors to 8 strobes. Using a 820 ohm 2 watt charging resistor, they will flash as fast as you want.

The 600 volt 6 amp SCRs work for triggering but you have to purchase name brand camera units.

I bought 140 units from The Electronic Goldmine and built up 32 including waterproffing only to find out they don't work.

[jmksparks]

I have a 110vac/220vac transformer and I use a full wave rectifier to charge the capaictors to 8 strobes. Using a 820 ohm 2 watt charging resistor, they will flash as fast as you want.

The 600 volt 6 amp SCRs work for triggering but you have to purchase name brand camera units.

I bought 140 units from The Electronic Goldmine and built up 32 including waterproffing only to find out they don't work.

Yes sir I did read this before, just agreeing with you. My thoughts on this matter is that the switching transistor on board is very sensitive had I more time this is were I would "play around" or am I of my trolley!

[Matt_Edwards]

FG,
I am returning to the same pretty soon.
I understand you have ~320Vdc to drive the pulse transformers. That is what I intend to do anyway. I am curious however, why you are using a SCR or a Triac to trigger the strobe. Why not a FET or just a HiVolt BJT like a MJE13007G?

Cheers
Matthew

[FireGod]

I am using the 320VDC to charge the main capacitor.

As far as the others, no answer. It only takes time and money to test these things.

[ukewarrior]

I too would love to know if this has had any more work done to it.

Thanks!

[Matt_Edwards]

in that case,
i will let you know how I go.

Cheers
Matt