Situation:
I've designed a photodetector circuit for my high speed chronograph.
The basic idea is two infrared gates connected to a dual analog comparator (LM393) with outputs connected directly to ESP8266 microcontroller (GATE_1, GATE_2). The Microcontroller measures time difference to get velocity of projectile. Simple stuff right?
Turns out not so much, I'm just an electronics hobbyist, most circuit diagrams and datasheets are way over my head.
The problem:
I've built the following circuit and got a PCB fabricated. Upon assembly I noticed that that one of my gate (GATE_1) outputs gets activated rapidly itself. I accidently pressed my thumb against the microcontroller and noticed that the pin stopped flickering and settled down but still worked when I shot a projectile. Then I narrowed it down to an unrelated pin on the microcontroller, a pin that isn't even connected to anything. I'm very puzzled.
Alas, I post here in hopes of wiser folk can spot errors in my design. Thank you.
PS: I should probably mention, there is a DC DC step booster on my PCB that is switched off to help narrow down the problem.
I've designed a photodetector circuit for my high speed chronograph.
The basic idea is two infrared gates connected to a dual analog comparator (LM393) with outputs connected directly to ESP8266 microcontroller (GATE_1, GATE_2). The Microcontroller measures time difference to get velocity of projectile. Simple stuff right?
Turns out not so much, I'm just an electronics hobbyist, most circuit diagrams and datasheets are way over my head.
The problem:
I've built the following circuit and got a PCB fabricated. Upon assembly I noticed that that one of my gate (GATE_1) outputs gets activated rapidly itself. I accidently pressed my thumb against the microcontroller and noticed that the pin stopped flickering and settled down but still worked when I shot a projectile. Then I narrowed it down to an unrelated pin on the microcontroller, a pin that isn't even connected to anything. I'm very puzzled.
Alas, I post here in hopes of wiser folk can spot errors in my design. Thank you.
PS: I should probably mention, there is a DC DC step booster on my PCB that is switched off to help narrow down the problem.
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