An Arduino-based DIY RC transmitter designed for ExpressLRS external TX modules, featuring simple hardware and open-source firmware.
Simple TX is an open-source, Arduino-based RC transmitter designed to work with ExpressLRS external TX modules. It provides a DIY solution for radio control of drones and other models, featuring customizable hardware, firmware, and 3D-printed enclosures. The project solves the need for an affordable, hackable transmitter that leverages the popular ELRS protocol for long-range, low-latency communication.
RC hobbyists, drone enthusiasts, and makers who want to build or customize their own radio transmitter using accessible Arduino components and open-source designs. It's ideal for those familiar with basic electronics, 3D printing, and Arduino programming.
Developers choose Simple TX for its simplicity, full open-source hardware and firmware, and direct compatibility with the widely-used ExpressLRS ecosystem. Unlike commercial transmitters, it offers complete customization, from PCB layout to shell design, at a lower cost and with community-driven updates.
Arduino based RC transmitter for ELRS external TX Module
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Compatible with ExpressLRS external TX modules across versions 1.0, 2.0, and 3.0, with updates merged from community contributions, ensuring longevity with the protocol.
Supports up to 500Hz packet rate for low-latency control, achieved through 400K baud UART optimization as detailed in the V0.9.3 update log.
Provides open-source PCB designs (Gerber files), STL files for 3D-printed shells, and a bill of materials, enabling full custom builds from accessible components.
Allows setting packet rates and power levels via stick gestures during power-up, simplifying user interaction without extra hardware buttons, as shown in update logs.
The ATMega328p microcontroller lacks half-duplex UART capability, preventing telemetry feedback from receivers—a admitted hardware limitation in the README.
Calibration requires enabling debug mode, serial monitoring, and manual value mapping, which is error-prone and technical, as described in the tips section.
Issues like buzzer support needing additional components (e.g., a triode) and reports of burned boards indicate bugs and design flaws, with warnings in the README.