ESP32 Forum

Hi everyone,

I'm working on a project using a custom Micro-ROS board based on the ESP32-S3. Currently, I only have access to a single 4-pin connector which provides:

- GPIO35
- GPIO36
- 5V
- GND

I need to connect multiple external sensors to the board, including:
- IR sensors (digital input)
- Sonar sensor (HC-SR04 — needs TRIG and ECHO)
- GPS module (UART)

Given the very limited available GPIO (only GPIO35 and GPIO36), I’m looking for advice on possible extension solutions.

My main questions:
1. What is the best way to expand this setup to handle at least IR and sonar reliably?
3. Are there breakout/expansion boards you recommend that would help with this setup?

I guess you'll need a second MCU as an "IO coprocessor" which handles your required inputs and outputs (esp. the timing) itself and communicates with the "main" MCU via one or both of the two signal lines you have available, e.g. via UART.