ESP32 Firmware Adds Transmit to Turn Chip Into Full SDR
Developer Murmel's early firmware lets the ESP32's 2.4 GHz radio transmit and receive, and it already works with gqrx.
A developer known as Murmel has released an early version of ESP32 firmware that adds transmit capability, turning the chip's 2.4 GHz radio into a full software defined radio rather than a listen-only one, according to hackaday.com. The firmware works with gqrx.
Murmel demonstrated the new capability by communicating between an ESP32-S3 and an ESP32-C6 using a Hellschreiber mode that Murmel devised.
Work is also underway on 802.15.4 modulation for the ESP32, which could allow the chip to speak ZigBee.
Earlier receive-only work
Last week, Hackaday reported on two apparently simultaneous hacks that used the 2.4 GHz radio inside many ESP32 variants to give raw access to radio samples, making it a listen-only software defined radio platform. The team behind that original ESP32 SDR work is called Espargos, and Espressif's API suggests the radios can tune down as low as 100 MHz.
Early hacks on the RTL-SDR set off a wave of hacker SDR radio experimentation.
Quick answers
What does the new ESP32 firmware add?
It adds transmit capability to the previously listen-only ESP-SDR hack, so the ESP32's 2.4 GHz radio can both transmit and receive.
Which software does the firmware work with?
It works with gqrx. Murmel demonstrated it by communicating between an ESP32-S3 and an ESP32-C6 using a Hellschreiber mode.
What is next for the project?
Murmel is working on 802.15.4 modulation for the ESP32, which could allow it to speak ZigBee.