Utility Meter Pulse Optical Counter (Home Assistant Glow)

An enclosure for my Home Assistant Glow utility meter sensor. Other designs I've seen had the microcontroller and sensor as separate items, I didn't see the need and wanted a single enclosure. 

I had ESP32 Mini on hand as otherwise, I would have probably built this around a WEMOS D1 Mini ESP8266 which would be slightly smaller.

Software

• ESPHome
• Home Assistant Glow
• Home Assistant

Hardware

• MHEtLive ESP32-Mini-Kit (ESP-WROOM-32) (aka WEMOS D1 mini ESP32)
• PhotoDiode with digital output
  • LED straightened to face out the top of the case
  • Pin connector trimmed to keep it small
  • Only 3 wires soldered:
    • GND
    • 5V
    • GPIO (I used GPIO16)
• M3 bolt, self tapped into the plastic

Printing

• Material: PLA Prusament Galaxy Black
• Print Settings (PrusaSlicer): 0.20mm Quality, 15% infill
• Supports: None

Assembly

• Modify photodiode sensor as above and secure to lid using M3 bolt
• Tilt the ESP32 board and push down to get past the lid catches
• Snap the case shut
• Adjust the sensor through the hole in the lid using a small cross-head screwdriver so that it only triggers when utility meter LED pulses.
• Mount the sensor to the utility meter using 3M command strip or similar.