flabbergast's kicad files
The controller MCU is STM32F042K6T7 - 32kB flash, 6kB RAM, DFU bootloader in ROM, LQFP-32 package. The BOOT0 pin for entering the bootloader on power up is brought out to a pushbutton on the bottom side of the PCB.
A.K.A. the bat board. A Teensy-sized breakout for STM32* MCUs in QFP48 package. Tested with STM32L052CxTx, STM32F072CxTx, STM32F103CxT6. Please see the main page (the bat board) for more information, documentation and how to make yourself and/or order one of these.
This is a simple shield for the bat board. The main purpose is to turn a bat board into an USB-to-serial device, but there are a couple of extra things (button, RGB LED, ...). Please see this page for documentation, some pictures and links to relevant firmware.
A half-mounted Pocket Beagle cape with RFM69 radio, atmega328p, RTC, atsha204, a few status LEDs, and a JST connector for Pocket Beagle backup power. See this page for some photos and a little documentation.
A small "USB-to-serial" board with FT231XS chip. It has the "standard" 6 pin header, with DTR and RTS like USB BUB III, so good for Arduino-like stuff and also some ARMs. The sligtly unusual features are:
- a reasonably beefy 3.3V voltage regulator for supplying 3.3V (more than the 50mA from FT231XS's internal regulator),
- a three-position switch, to select between supplying 5V, 3V3 and no power on the "power" pin,
- when "no power" is selected, the logic levels are kept at the level of the "power" pin, meaning that the target board provides the reference voltage (this should work down to 1.8V),
- a Schottky and some resistors to limit the logic levels if it goes beyond 3V3 - this doesn't quite work completely exactly, so e.g. with 5V on the "power" pin, the voltage on TX and DTR is 3.55V.
This is a very old and very small "breakout" of the JTAG-ish 2x5 1.27mm header to eight 2.54mm holes, with the outer row of 4 has the SWD pins.
My attempt for something like jeenode zero, but with TSSOP-20 packaged STM32L041 (or L031 - the only difference is L041 has AES built in). It can be used for actual sensor deployment, but it was just a quick design to try the MCU out. So all the pins are out, some of them multiple times, no attempt at making it "as small as possible". Has a LED, BOOT+RESET buttons, RFM69CW footprint, voltage regulator and "standard" 6 pin UART jnz-like header. And a few solder jumpers: for connecting RF69's IRQ to a pin (which supports EXTI), for disconnecting the regulator from the power net (so that a potential battery doesn't try to back-feed the regulator), and for disconnecting the boot button from an extra pin. Because there is space on the PCB, it is (hopefully) self-documenting.