Airgun silencer part 3
this continues from part 2.
I ordered a Schmitt Trigger 3-input AND gate. It has a nice and wide Vcc input range (1.65V – 5.5V) and is nice and fast (max 4.1ns @3.3V, and faster (around 2ns) @ 5V) and coms in a nice small 6-pin SOT23 package.
I connected the outputs of the OPL550 phototransistors to inputs A & B respectively and input C to Vcc. Now I have a 3pin interface.. Vcc, GND and the output that has the 2 pulses…
Here we can see the output of my TDR (a 12 ft-lbs gun), shooting a H&N Sport Baracuda (10.65gr) at around 722fps (the sensors are 50mm apart in this prototype)
Next to get it into the micro and out of the USB port…
…continued on part 4…