Well, I am working on a project that involves a disposable camera. I am not going to reveal anymore than that, but it is working, and should be finished soon, assuming everything goes as planned. I did want to share some of the dangers I have found with working with flashes on one of these cameras. It looks relatively benign on first glance, but don’t let that fool you. The rather large capacitor that you see on the board carries an amazing 300 volts. Just take a look at this picture above. That tiny speck on my ring finger is completely dead skin, caused by me touching the circuit board. If you look closely you can see a more faint spot on the bottom left of my ring finger. If you look even more closely, you can see an arc, where the 300 volts of electricity traveled between the two points. I jerked my hand back so hard and fast, it was amazing the body can react so violently. I am lucky that I did not hit the table.
Now there are other dangers from working on these things. I found an old camera that I had lying around. (You see, I never develop film. That is why I had to go digital.) Anyway, as you can imagine this camera was ancient. It was like from when I was in High School. Which had to be 7-8 years ago. I graduated in ‘98. Anyway, I saw the battery, and pulled it out, and of course got battery acid on my finger. I did not think much of it, and I wiped it off with a paper towel. About 10 minutes later, I felt this burning, and saw that where the acid was, the skin had completely died. Now it looks as if my finger is rotting off. Funny enough, this is the same exact finger that I got some bacterial infection on from Microbiology lab when we were culturing bacteria. I think I have killed all of the nerves in that finger, cause I can’t feel anything anymore. 
You can see this on the top index finger.
Anyway, be careful on your projects. 300 volts across the heart could kill a person. There have been people killed by touching large capacitors from Television sets. Always discharge them, and remove the battery. Don’t just stick a screwdriver accross the terminals, it can ruin your screwdriver, and the capacitor. Take a 100 ohm resistor, and short out the terminals. In a matter of seconds, it will be drained. Always use a voltmeter, to see if there is voltage on these caps before touching them. 300 volts hurts!
3 Responses to “Dangers of Disposable cameras”
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Then the question is, what current is flowing through the body from a cap at 300 volts? I guess it depends on the resistance of the body. If the current passes through the heart though, it can cause it to go into atrial fibrillation, or worse ventricular fibrillation, at which time you are toast. Actually 100-300 mA across the heart can cause ventricular fibrillation. So it doesn’t really matter that the voltage does not kill you, because there is enough charge built up in some capacitors to deliver a high current. Regardless, caps can be very dangerous.
I am glad that mine did not “melt” to me.
No, I am not making a rail gun, or a tazer, though they would be fun. I have an original project that I have been working on, involving a disposable flash, and finally my new PIC chip. I am using a 12F675. I will post a how-to project on it soon. I am almost done with it, just some final tweaking,and soldering left to do.
Actually 30mA is enough to cause a problem with the heart. As for the capacitors, NEVER discharge them with a plain wire (or a screwdriver) as you could make the EXPLODE.
This is particularly true with defibrillators………