808 Camera Automation

I choose the 808 spy cam for my high altitude balloon project because it’s weight and it’s price. But as I wanted to take pictures during the flight I needed some hack to automate the camera. I found a nice hack , it uses an ATTiny13a driving a relay. But as I feel more comfortable with Microchip instead of Atmel, and I thought I can improve the design I did my own hack (yes, yes… excuses. I just want the fun). I start with the PIC12F675, because it’s tiny, and well I have it. I didn’t use a relay to the mode button: I found that the power button works with a + signal, but the mode button needs a ground signal, and must be trough a resistor (220 Ω worked). While I was testing I found the camera hangs after 1600 photos, so I added a reset function (the button in the lateral). It’s in the schematics, but not in the photo.

Also I added a LM317 regulator to provide the 3.8 volts for the camera, so I can power the camera externally from 6 to 9 volts. An this is very important, because I found the camera very sensible the voltage: it just will work with more than 3.55V but less than 3.95V, and should be in that range in sleep and working (~150mA). So as I will switch the power with a MOSFET it’s internal resistance would have been a problem. Now I can switch before the LM317 assuring 3.8V anytime for the camera.

I  did my code for a secuence of photos (60) with 4 second of interval,  20 second of video, and repeat. But, it could be anything you want. If you need the code, just send me an email.

My wish list:

• A way to detect if the camera hangs (detecting the led activity)
• A PC program interface to easily change the number of photos, seconds of video, intervals, etc.

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