Shows the distance from a ultrasonic sensor on a 3 digit 7-segment module.
Hardware:
- Arduino Uno
- HR-SR04 ultrasonic sensor
- MCP23017 I/O Expander http://ww1.microchip.com/downloads/en/devicedoc/21952b.pdf
- Kingbright BC56-12SRWA 7-segment module (common cathode)