If the Challenger RP2040 board’s built-in Wi-Fi didn’t have the kind of range you were looking for in an IoT or home automation project, Invector Labs has you covered with its new LoRa model.
With a range of 15 miles, if you have line-of-sight, Hope RF’s RFM95W radio transceiver module gives it a slightly longer communication distance than Wi-Fi in LoRa mode, which also allows you to transmit data at 37.5kbps. It is connected to the SoC RP2040 via the SPI channel of the GPIO, with an antenna connected by a U.FL connector. If you want to increase the power, the bandwidth goes up to 250kbps in FSK mode.
The new Challenger board, compatible with the Adafruit Feather form factor as well as CircuitPython and MicroPython, retains the original Challenger’s RP2040, but completely loses Wi-Fi compatibility in favor of the longer range system. The surprisingly long throw comes from a combination of a high-sensitivity crystal and an integrated +20dBm power amplifier. Since LoRa trades transmission speed for range, don’t expect to get the best bandwidth at the greatest distances. A typical LoRa device reaches up to three miles in urban areas and up to 10 miles or more in rural areas with line of sight.
Also new since the Wi-Fi version is a 2.0mm JST connector for rechargeable LiPo batteries and an internal battery charger circuit that allows charging via USB. There’s a USB Type-C port for power and communication needs, and the tiny board weighs just 0.009 kg (0.317 ounces) and measures 5.07 x 2.28 x 0.72 cm (1.96 x 0.89 inches x 0.28 inches).
Programming the board is made possible through CircuitPython, MicroPython, and an Arduino library developed by Earle F. Philhower.
LoRa is a proprietary data transmission protocol owned by Semtech that uses unlicensed sub-gigahertz radio frequency bands such as 865–867 MHz and 2.4 GHz. Adafruit already has a board that uses it, the RFM95W, which has been used in projects such as model rocket telemetry.
The Challenger RP2040 LoRa is available from the Invector Labs store, but was out of stock at the time of writing. Other versions of the board include one with LTE and one without wireless capabilities, but retaining the LiPo battery charger circuitry.