custom firmware on 24GHz Seeed radar modules

I figured out that the MicRadar-branded LQPF48 package on Seeed's MR24D11C10 radar module is actually an AT32F403ACGT7, which turns out to be a capable Cortex-M4F MCU with a 12-bit ADC.

In normal operation, the AT32 samples downconverted IQ from the radar IC (an Infineon BGT24LTR11), does some math, and outputs human/no-human/human-fall-down over UART.

The AT32 also features a USB full-speed controller, and the USB pins are populated on the 5V pin header on the module.

One thing lead to another, and I prototyped some firmware which samples IQ at ~285600 samples/second, and streams it over USB to a Python script on the host. The sample rate is constrained by USB speed, but the MCU itself can sample at least 2Ms/s.

proof-of-concept

This is very much a proof-of-concept and doesn't include any control over eg. tuning, but should be a good place to start if you too impulse-bought some radar-modules from Seeed :)

requirements

• Seeed 24GHz human-detector radar module (MR24D11C10 or MR24BSD1)
• sacrificial USB cable
• J-Link (or some other OpenOCD-compatible SWD programmer)

wire up the module for USB and SWD

• I connected a USB cable by replacing one end with some jumper wires.
• If you're using something other than a J-Link for SWD, you'll need to update the OpenOCD invocation in the Makefile.
• pinout.jpg

patch and build openocd

Patch OpenOCD to recognize the AT32F403A as an STM32F1xx:

git submodule update --init
cd openocd
git apply ../openocd.patch
./bootstrap
./configure
make -j
cp openocd/src/openocd openocd/tcl/
cd ..

build and flash the firmware

make
make flash

stream into baudline

Make sure baudline is in your path, and then run the following command to reset the module and start streaming IQ to baudline.

make reset && sleep 1 && ./stream-iq.py | baudline -stdin -channels 2 -quadrature -record -fftsize 2048 -flipcomplex