Nose Poke Circuit

Just finished my nose poke circuit.  It consists of a beam break that triggers an notification LED to come on and toggles output state.

UPDATE:

Turns out that the transistor for the Poke Notify LED sucked current away from the output, reducing the "high" signal voltage sometimes to below TTL levels.  Replacing the transistor with a mosfet (in this case an AND gate) solved the issue.  Here is the new circuit which uses the AND gate to drive both the TTL output and the Poke Notify LED.

Hacking Agama V-1325R IR Camera

As part of my research, I do experiments with rodents (rats).  I train rats to do a number of tasks that allow me to ask them how they perceive odors.  Rats like to work in the dark and I monitor them with an IR camera.  As a cheap IR camera, I bought an Agama V-135R cam with built-in IR LEDs.  However, one annoying thing about this camera is that the IR LEDs must be turned on via software and are programmed to shut off every 45 mins.  I just want them to be on all the time!  So I opened up the camera and found a way to keep those guys glowing!  The LEDs were wired as two garlands of 2 leds plus a 50 Ohm resistor.  This makes sense:

USB Vcc = +5VDC
IR LEDs drop = ~1.75 V Each
Leaving 1.5 V dropping over R=50 Ohms --> I = 30 mA

The two garlands go to ground through a transistor.  I simply shorted the transistor with a fine copper wire!

There are 4 LEDs on the Agama 1325R connected as two garlands.  They receive power from a 5V Regulator and go to ground through a transistor switch (right top).  I shorted this transistor with a fine copper wire.