Example project for the ePulse Feather. It runs some tests and prints the test results as JSON formatted string to the serial console.
This firmware is made for the web based https://iot-flasher.thingpulse.com/ The build script generates a single firmware file. You can find it at .pio/build/esp-wrover-kit/app-firmware.bin
You can buy the ePulse Feather here: https://thingpulse.com/product/epulse-feather-low-power-esp32-development-board/