Is it just me or was it hot over the last week? Looks like the dog-days of summer are finally here. Since going around in sultry 35-40C heat doesn't qualify as fun picture taking conditions, I decided to stay inside with the air conditioning running full blast and tinker. Thus came to life my third contraption: the Flash Powerbox. This project started out as something cheap and simple that would finally put to some good use the old electronic flashes I had lying in a drawer that haven't seen the light of day in more than 10 years. Then, for some odd reason quickly became hell on wheels in both its complexity and rising costs. So what started as a cheap project is ending up costing me well over 50 bucks in miscellaneous parts from the electronics surplus store.
It all started with a simple idea (like all other projects that seem to take on a life of their own after some point): wouldn't it be fun to have a way to fire many flashes simultaneously without using a slave trigger? Then came: wouldn't it be even cooler if I didn't have to put AA's inside each flash? And you can already see the ball starting to roll down the hill?
So for the project, I had a few things I ended up wanting really bad:
A box with larger capacity batteries for more power.
The possibility to use AC current in case the batteries failed.
The possibility to use some pre-assembled and cheap wires to bring both power to the flash units and trigger the flashes.
So, I first thought of bundling wires and connect them using audio plugs. But that would have been too expensive and just a mess to connect. Then I thought about using regular phone cord for connecting the whole thing. It already has 4 connectors, costs only 1$ for a good length, I have a ton of them that came with previous telephones and modems... the perfect choice.
First problem I encountered is the power supply I had blew. So I ended up getting a better one. Then came part of the wiring nightmare. I hadn't thought that since the phone cables are straight, the red, black, green and yellow wires become yellow, green, black and red at the flash end (no wonder nothing would work!).
Also, to put additional wires inside those already tightly packed units requires better than average soldering skills. So I had to enlist my dad for part of the work. One of the issues with working inside the flash units is that rather nasty looking capacitor. Just to give an indication on how powerful they can be, when I had to discharge one using a pair of well insulated needle nose pliers, the capacitor actually melted a part of the tip and blackened it for a good 1/4 inch long. Not to mention producing a loud snap which almost had me go to change underwear.
Once I thought I had everything wired up correctly (the flashes would charge up correctly) I came to the realization that there was another problem: only one of the two flashes would fire when I pressed the test button... at that point, I had already overspent quite a bit and couldn't figure out exactly what the problem was. Then it dawned on me: my flashes were different make and age. Contrary to my belief, the flash trigger voltage isn't the same for all models. The flash with the lowest trigger voltage will actually prevent the other one from firing... a bad thing.
After a bit of research on the internet, I came up with a solution: make all the flashes trigger using the same voltage. This involved adding a special chip inside each unit (like there was a lot of free space in there) and re-wiring each flash. Hence the mess of spaghetti wires in each of the phone boxes I used. I had to use what is called an opto-isolator with TRIAC output... whatever this really means. This is essentially a small chip with a miniature LED and a phototransistor inside the same light tight casing. When I turn the LED on using the 6 volts which also power the flash (I use a loopback to the powerbox for the trigger), it opens a switch to short the original flash trigger. It's that simple and works like magic.
Now, I finally have a working system! It is light and used up a ton of old stuff I had lying in the drawers of the workshop. It uses 4 D cells to power up to 4 flashes. When using the wall plug, it powers the flashes in a fraction of the time.
I hope you all enjoyed reading about this other adventure in Rube Goldberg territory.
All I hope is I will have as much fun using it as I had building/fixing it...
[Sorry, image deleted during forum software upgrade. Please re-upload if so inclined.]
