NOTE: Documentation in progress!

Introduction

The 12V -> 5V @ 4A Buck Converter + ELRS Board is intent for several foam fixed wing planes at the Waterloo Aerial Robotics Group. It includes a ESP32-C3 for PWM signalling and SX1281 for RF control over ELRS, as well as the requisite power electronics to have the system be powered by a single 12V input (1x 3S battery).

This implementation is designed to optimize and integrate the system of the foam fixed-wings, which currently requires a separate buck converter (previously using 12V->5V @ 5A Buck Converter Board), and a commercial, off-the-shelf ELRS receiver (https://betafpv.com/products/elrs-micro-receiver).

By implementing the two main features on a single 30.5x30.5mm board, we save on weight, size, and complexity of the foam plane’s overall system.

This board does not currently integrate an ESC for motor control.

Specs

6x PWM header pins for servo control (2.54mm pitch)
- 2 are placed to be connected to ESCs
1x input XT60-M connector
- designed for 3S battery (12V input)
2x output XT60-F connector
- 12V output for up to 2 ESCs
1x U.FL connector for external RF antenna
- Connected to the RF IC. Impacts RC performance.
1x chip antenna for ESP-32C3
- Can be used for WiFi flashing.

Usage

This board is designed to use a single 3S battery for input power. This will split the power into two output XT60 connectors, and feed to the buck converter, which, in combination with an LDO, powers the rest of the device.

The power rail is rated for an absolute maximum of 16.9V, accounting for LiPo battery overcharging and input transients (voltage spikes from hot-plugging a high-inductance battery). Usage of a battery with an anti-spark connector is recommended.