Earlier today the CaribouLite crowdfunding campaign on CrowdSupply successfully completed it's crowd funding phase with over 600 backers and $134,000 raise. The team have noted in the latest update that they are now moving on to the production stages with the estimated shipping date still indicated for May 25, 2022. Now that the campaign has ended the pricing has increased slightly from $119 + shipping to $138 + shipping.
The CaribouLite is a software defined radio HAT for the Raspberry Pi with a 30 MHz - 6 GHz frequency tuning range, 13-bit ADC, 2.5 MHz bandwidth and one TX and one RX channel.
Back in June of this year we first posted about the upcoming CaribouLite product which is a software defined radio HAT for the Raspberry Pi. The project has just launched on Crowd Supply with a price tag of $119 for the CaribouLite, and $69 for a CaribouLite ISM only band version. The product is expected to ship in May 2022. CaribouLabs write:
CaribouLite is an affordable, open-source, dual-channel software-defined radio (SDR) platform—and an SDR-focused FPGA development framework—implemented as a Raspberry Pi (RPi) HAT. CaribouLite turns your Raspberry Pi single-board computer (SBC) into a self-contained, dual-channel radio Tx/Rx that spans a wide tunable frequency spectrum up to 6 GHz.
The CaribouLite RPi HAT
The CaribouLite is entirely open source and designed for makers, hackers, educators, and researchers. It comes in two versions, the full and ISM band only versions. For most people the full version will be most desirable as it covers the full 30 MHz - 6 GHz range. However, certain projects may want to make use of the ISM band only version as they note that it may easier to obtain regulation compliance.
The full version comes with two TX/RX half-duplex channels, with channel one covering 30 MHz to 6 GHz, and channel two covering sub 1 GHz only. Both channels use a 13-bit ADC, capable of a bandwidth of up to 2.5 MHz maximum. The unit is capable of up to 14 dBm of transmit power.
The libcariboulite drivers support Soapy API, meaning that many SDR programs including SDR++, GQRX, CubicSDR and GNU Radio will be able to support the CaribouLite.
One interesting design feature is that the CaribouLite does not interface with the Raspberry Pi via USB or Ethernet which is how most SDRs interface. Instead they make use of the SMI (Secondary Memory Interface) connector, which is a high bandwidth interface available on Raspberry Pi's. This is a very fast interface allowing the IQ samples to stream back and forth, however the disadvantage is that the CaribouLite will only work on Raspberry Pi devices. Although it should be possible to use the Raspberry Pi as a host device if you wanted to use the SDR on a PC.
One problem is that we note that most Raspberry Pi resellers are out of stock and the component supply crisis appears to have slowed Raspberry Pi production. So this may be an issue for purchasers who do not already have their own Raspberry Pi. However, given that the CaribouLite ships in May 2022, there may still be time to obtain a Pi.
Given the low cost, specs and features, this appears to be quite an interesting SDR that we are excited to get our hands on. Combined with a Raspberry Pi Zero we can imagine multiple portable use cases and projects that will come from this product.
Thank you to David for submitting news about his company Caribou Labs' new product called "CaribouLite" which will be a software defined radio HAT for the Raspberry Pi. The product is currently in the pre-launch stage over on Crowd Funding platform CrowdSupply and you can sign up for future updates on the release. David writes:
I'd like to inform you of a product we have developed called CaribouLite board, which is essentially a Raspberry Pi HAT that enabled up to 6GHz SDR capabilities Tx and Rx, and an additional TxRx Sub 1GHz channel.
It uses Microchip's modem AT86RF215 as an I/Q ADC, DAC and frequency conversion is done using Qorvo's RFFC5072 IC. An FPGA (ICE40) is used to stream data packets (I/Q @ 13 bit x2 / sample) back and forth between the Raspberry Pi and the Modem, over an interesting fast interface called SMI.
I think this project brings new ideas to the table and would be interesting to the SDR community.
The use of the SMI interface is an interesting idea and not something we see utilized often as apparently the official documentation is sparse and poor. But David notes how it allows for up to 500Mbit/s of data to be exchanged between the FPGA and Raspberry Pi, although the true throughput depends on the specific Raspberry Pi model used. Regardless the SMI data rate is more than enough for the 120 MBit/s required by the two streams of 13-bit IQ data that the CaribouLite generates.
The campaign also notes that the sample rate is 4 MSPS, with 4 MHz bandwidth, and up to 14 dBm of transmit power is possible. They also note that they are planning to release a wide range of library code that allows for use cases such as wide range spectrum analysis, a signal / protocol generator, an analog / digital DAB+ receiver, an ADS-B receiver and more.
The software and hardware design is also fully open source and available on GitHub.
The CaribouLite SDR HAT mounted on a Raspberry Pi Zero
