# Chronograph ## Description This is a 2 stage IR sensor circuit intended to be used as a ballistic speedometer/chronograph for my Coilgun. I based it off a common design for IR proximity sensors. There are 2 output pins to a microcontroller, and +/-pins for 2 IR receivers, 2 IR emitters, and 2 green LEDs to show when the stage is active. When the beam is broken the voltage on the microcontroller output pins will change, allowing me to code proper coil stage firing timing. The potentiometers are for tuning the sensitivity. ## Project Details - **Owner:** aetherwolf - **Created:** 10/17/2023 - **Last Updated:** 10/10/2025 - **Visibility:** Public ## Key Components ### U1 — [LM393N/NOPB](https://www.flux.ai/adrian95/lm393nnopb.md) - Datasheet URL: https://www.snapeda.com/parts/LM2903D/Texas%20Instruments/datasheet/ - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Texas Instruments Inc. - Manufacturer Part Number: LM393N/NOPB - Part Type: Integrated Circuit **Pins:** - 1IN- [pin 2] - 1IN+ [pin 3] - 1OUT [pin 1] - 2IN- [pin 6] - 2IN+ [pin 5] - 2OUT [pin 7] - GND [pin 4] - VCC [pin 8] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/aetherwolf/chronograph](https://www.flux.ai/aetherwolf/chronograph).* --- *Generated from [https://www.flux.ai/aetherwolf/chronograph](https://www.flux.ai/aetherwolf/chronograph)*