CaribouLite RPi HAT open-source SDR Raspberry Pi HAT tunes up to 6 GHz (Crowdfunding)

CaribouLite RPi HAT is an open-source dual-channel software-defined radio (SDR) Raspberry Pi HAT – or rather uHAT – that works in the sub-GHz ISM range and optionally the 30 MHz – 6 GHz range for the full version.

Developed by Israel-based CaribouLabs, the micro HAT is equipped with a Lattice Semi ICE40LP1K FPGA, a Microchip AT86RF215 RF transceiver, two SMA antenna connectors, a Pmod expansion connector, and designed for any Raspberry Pi board with a 40-pin GPIO header.

CaribouLite RPi HAT specifications:

FPGA – Lattice Semi ICE40LP with 1.28 kLE
RF Chipset – Microchip AT86RF215 Sub-GHz / 2.4GHz transceiver
Qorvo’s RFFC5072 integrated Mixer IC (for full version only)
Tuning Range
- CH1
  - Full version – 30 MHz – 6 GHz
  - ISM version – 2.4 – 2.4835 GHz
- CH2 – Sub-1GHz
Max Sampling Rate – 4 MSPS
ADC/DAC Resolution – 13-bit
Max RF Bandwidth – 2.5 MHz
Transmit Power – up to 14 dBm @ISM frequencies
Frequency Stability – <±2 ppm
Dual-half Duplex operation
Clock – 26 MHz TCXO
2x SMA antenna connector
Host interface – SMI (Secondary Memory Interface) interface to Raspberry Pi
Optional GPS support with add-on
Expansion – 8-bit PMOD connector for GPIOs, GND, 3.3V
Misc – User switch and user LEDs, RF activity indication LEDs
Power Supply – 5V via Raspberry Pi header; LDOs delivering 3.3V, 2.5V, and 1.2V signals
Dimensions – 65 x 30 mm
OSHWA certification – IL000002

The HAT also includes an EEPROM with board information, device tree overlay, and drivers to be automatically recognized and configured by the Raspberry Pi board attached to it. The company also provides libcariboulite library, SoapySDR drivers, device-tree overlays, sample code, firmware, and hardware design files (PDF schematics only) on Github. The software enables the board to be used with SDR programs such as SDR-PlusPlus, GQRX, CubicSDR, GNU-Radio, and more.

The uHAT interfaces with the Raspberry Pi through the SMI (Secondary Memory Interface) of the Broadcom BCM2xxx processor which I don’t think I ever heard of, and CaribouLabs confirms the ” interface had not been fully investigated previously”. You can find more details on the Caribou-SMI API Driver page.

CaribouLabs has launched the CaribouLite RPi HAT on Crowd Supply with a $112,500 target. Rewards start at $69 for the CaribouLite-ISM (Sub-Ghz + 2.4 GHz), and $119 for the model supporting up to 6 GHz tuning. Shipping adds $8 to the US, $18 to the rest of the world, and deliveries are scheduled to start at the end of May 2022.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.