ESP32 RC Remote

A home-made, two-joystick remote control and a matching receiver, for driving my own radio-controlled builds without buying a commercial transmitter.

The handheld transmitter is a 3D-printed case around an ESP32-C3 board, two thumbsticks and a rechargeable battery. It talks straight to an ESP32 in the vehicle using ESP-NOW on 2.4 GHz, a direct board-to-board link with very little lag and no Wi-Fi router or phone signal needed. It's meant for custom RC projects such as off-road rigs or bait boats.

How it works

• Direct link. ESP-NOW sends short packets straight from one ESP32 to another, fixed to Wi-Fi channel 6 (2.437 GHz), with the transmitter at its maximum output of 19.5 dBm.
• Four axes, two buttons. Each thumbstick gives an X and a Y reading, read by the ESP32-C3's 12-bit converter (0–4095), plus a push button.
• About 20 updates a second. The transmitter sends every 50 ms.
• Rechargeable. A single 18650 lithium-ion cell, charged over USB-C through a TP4056 board, with a step-up converter for the electronics.
• Receiver. A classic ESP32 in the vehicle drives the motor controllers, servos or relays, and uses its onboard LED to show the link status and failsafe.

Parts and cost

The case

The transmitter is built from stacked, screwed-together panels. That keeps it stiff and means any part can be opened up to swap or service the electronics.

• Faceplate: recessed cut-outs so both thumbsticks move through their full range.
• Standoffs: built-in bosses for M3 self-tapping screws or heat-set brass inserts.
• Electronics: channels to hot-glue or plate-mount the TP4056 charger and the ESP32-C3 next to the USB cut-outs.

Print settings: PETG (tougher, more UV- and heat-resistant than PLA), 0.20 mm layers, 20–30% grid or gyroid infill, 3 walls and 4 top and bottom layers. Supports are only needed around the counter-bored M3 holes and a few cut-outs.

Wiring

Transmitter (ESP32-C3 SuperMini)

Receiver (classic ESP32)

The data packet

Each transmission carries both sticks and both buttons in one small structure, which the receiver unpacks with the same definition:

typedef struct struct_message {
    int leftX;
    int leftY;
    bool leftBtn;
    int rightX;
    int rightY;
    bool rightBtn;
} struct_message;