This board is centered around an STM32L412CB, which has a Cortex-M4 running at 80 MHz, 128K of flash, 40K of RAM, single precision FPU, USB FS Device, and a typical set of other peripherals.

The board is somewhat compatible with the STM32 Nucleo-32 boards, which are somewhat compatible with Arduino Nano. This is mainly so that I can use the Nano terminal blocks (https://www.amazon.com/gp/product/B095XVVGQ8).

The main purpose of the board is as a voltage/current logger for the study of battery charge/discharge curves. For this reason it has a large current sensing resistor connected to the L412’s op amp.

Another unique feature, for a board this size, is that it has an ETM Trace connector. This board works nicely with Segger’s J-Trace probe and Ozone debugger to provide instruction trace. The L412/L422 is the only STM32 Cortex-M4 (as far as I know) that has trace in a package smaller than 100 pins.

The KiCad schematic and pcb files are included in the download. All the parts are available from Digikey.

As of this writing I am bringing up basic software. I am also working on an update of the board to fix a couple minor bugs. I have not tried out the analog stuff yet.

I recommend Nefastor’s USB tutorial and STM32_VCP library:
https://nefastor.com/microcontrollers/stm32/usb/stm32cube-usb-device-library/usb-fundamentals/ https://github.com/Nefastor-Online/STM32_VCP

I followed the steps, wrote a little bit of my own code, and now I can use the L412’s native USB port as a virtual serial console, providing printf and getchar.

Here’s a tiny board for rumble motor

pad GND > (one of the) GND of arduino

pad 5 > pin5 of arduino board

pad VCC > VCC of arduino board

pad + > positive of rumble motor

pad - > negative of rumble motor

THANKS to Boxdgm / TinkerDadNerd / Jaybee for testing and helping me.

For REV. 2 owner

Simply wire a jumper wire from GND of arduino board to the 1 leg f trasistor.

That' all folks!

GReX FEM

74x74 VFO adapter for I & Q inputs. 14 pin socket adapter

Basic OpenCV or OpenPnP test calibration grid and test calibration dot. I would recommend ordering this version with “After Dark” since this relies on the bright copper on black substrate. Side 1: 2mm Square Calibration Grid (Overall: 20x20mm) Side 2: 1mm Square Calibration Grid (Overall: 20x20mm) Overall this is an ok calibration board. I prefer the standard solder mask based versions, this after dark version isn’t as good.

Basic OpenCV or OpenPnP test calibration grids. Do not order with “After Dark” since this relies on the dark purple mask on bright copper. Side 1: 2mm Square Calibration Grid (Overall: 20x20mm) Side 2: 1mm Square Calibration Grid (Overall: 20x20mm) Overall this is a great and very accurate calibration board. I prefer the standard solder mask based versions, the after dark version wasn’t as good.

Basic OpenCV or OpenPnP test calibration grid and test calibration dot. Do not order with “After Dark” since this relies on the dark purple mask on bright copper. Side 1: 0.5mm Square Calibration Grid (Overall: 20x20mm) Side 2: 1mm Dot Overall this is a great and very accurate calibration board. I prefer the standard solder mask based versions, the after dark version wasn’t as good.

UBMP4.3 is a simple, versatile, and inexpensive microcontroller development system for anyone.

UBMP4.3 was designed for learning or teaching PICmicro programming using either Microchip’s MPLAB X IDE or the cloud-based MPLAB Xpress IDE. Its USB bootloader allows UBMP4.3 to be programmed in C using almost any device – including Chromebooks!

UBMP4.3 Hardware Features

• Microchip PIC16F1459 USB-capable microcontroller with 8k words of program FLASH (6k words free when using the USB bootloader), 128B of user FLASH, 1kB of RAM, 10-bit ADC, and a built-in temperature sensor
• 5 built-in pushbuttons
• 5 visible light LEDs
• 1 piezo beeper output
• optional 8-pin header for PORTC I/O pin expansion (great for servos, a SONAR module, NeoPixels, an LCD display, etc.)
• optional IR LED output for remote control transmitter applications (or a high-current transistor-driven output)
• optional IR demodulator for remote control decoding
• optional IR phototransistor or visible-light ambient light sensor for light sensing
• USB 2.0 type-C port for power and programming (now works using USB-C to USB-C cables in addition to USB-A to USB-C cables/adapters)
• 6-pin ICSP (In-Circuit Serial Programming) header for PICkit-4

Go to mirobo.tech/ubmp4 for more information.

Kian Ryan’s RS232 for Raspberry Pi Zero project. See his blog at https://www.kianryan.co.uk/2022-11-25-rs232-null-modem-hat-pi-zero/.

4 band processor board for the TPC-100 Texar Prism Clone multiband audio compressor. Details at https://ornerscorner.neocities.org/PrismClone

Display board for the TPC-100 Texar Prism Clone multiband audio compressor. Details at https://ornerscorner.neocities.org/PrismClone