I built a simple night vision set up using a model A RPI, pi NOIR camera, and car backup camera monitor. I made a simple infrared light by wiring 4 sets of 6 LEDs in series, so 24 total, let's see if I can do a terrible ascii style circuit diagram
____>_>_>_>_>_>__ |___>_>_>_>_>_>__| |___>_>_>_>_>_>__| |___>_>_>_>_>_>__| | | | \ |_____||_________|
where > is an LED, \ is a switch, and || is a 9V battery.
It works pretty well, but isn't practical because the RPI and monitor are plugged into the wall. That LED circuit is the limit of my electronics ability, so I might ask a dumb question or 10. Some poking around on the internet suggests I use something like this: http://www.suntekstore.com/goods-14002072-lm2596_dc-dc_step-down_adjustable_power_supply_module.html but I've never seen one before and don't know where the inputs or outputs are. Do you think I'd be able to run the RPI and monitor on 1 of these set to 5V and run the LED array directly on 9V? ( a series of 6 LEDs uses 9.6V, so I'm not afraid of burning them up)
Eventually I'd like to replace that manual switch with a transistor and control it from the GPIO pins, but I don't know what pin would be best, never used them before.
Also, any suggestions on a battery big enough to do this?
EDIT: Here are the LEDs I used: http://www.adafruit.com/products/387
They are 1.6 forward voltage and 100mA continuous current. I would have done 5 groups of 5, but one didn't work so I went with 4 groups of 6. 6 in a row seemed easier because 6 x 1.6 is 9.6V, so I figured the LEDs would eat up all the voltage from the 9V battery and I wouldn't need a resistor to take care of the rest. I'm not 100% sure what I'd use this for yet. If I can run the monitor, RPI, and LEDs off battery for a decent amount of time, I could strap it to a helmet and make a poor man's night vision goggles. I could also remove the monitor and set it up as a night time camera for watching animals outdoors. If I can't make a battery practical, could just use it as a surveillance camera in my house.
A rechargeable battery would be nice, and I've seen a few people using those USB battery packs for recharging cell phones, but but I've only seen them at 5 volts.