Shared Projects by dewhisna

The Optical Interrupter Protoshield board the for ProMini PiDuino HAT was designed to interface two off-the-shelf optical reflective sensors to the RPi via an Arduino ProMini.

The optical reflective sensors are used to detect the presence of an object by reflecting an infrared LED back to a phototransistor. The Arduino ProMini on the PiDuino HAT will allow “real-time” sensor timing with an accuracy of +/- 4uSec, using a standard 16MHz ProMini board.

Since the interface circuit required for the Optic Interrupter is small relative to the board size needed to fit the standard Arduino Uno pinout, this board was designed as a complete prototyping shield. The two test switches for testing the interrupter inputs have been left floating with breakout pads so they can be tied to any circuit. A reset button and user defined LED have been added in addition to a power LED and D13 LED.

Since the ProMini PiDuino HAT uses standard Arduino Uno footprints, this board can also serve as a prototyping shield for other Arduino boards and/or is interchangeable with either platform.

The V+ bus is tied to the IOREF voltage, allowing operation at either 3.3v or 5v and there’s extra connection pads for all Arduino I/O pins.

The ProMini PiDuino HAT Board for the Raspberry Pi 3 allows mounting of an Arduino ProMini to a Raspberry Pi as a HAT. Functionally, this board is similar to an Alamode board but without real-time clocks, GPS interfaces, and servo breakouts that aren’t needed for most projects and it’s designed to actually fit the Pi without having to insulate things to keep it from shorting out.

The primary use is to breakout connections for I2C, both 3.3V and 5V ready, and tie the ATmega328 of the ProMini to the Pi as a coprocessor for real-time I/O processing without needing a real-time kernel on the RPi.

The ProMini can interface either via asynchronous serial or as an I2C-slave. The ProMini reset can be driven via GPIO17, allowing full Arduino programming of the ProMini directly from the RPi Host.

Three RPi GPIO’s are also broken out to direct-connect ports for use with interfacing things like single-wire hygrometers. And all GPIOs from the RPi that are used for I/O by this board are ESD protected.

It has a standard Arduino Uno R3 shield connector footprint for add-on boards.

It also supports the ID EEPROM as per HAT spec, but will work on older 26-pin RPi platforms too, sans the ID EEPROM.

The ProMini board was chosen because it’s actually more price effective than manually mounting the equivalent circuitry directly to this board. It also uses the off-the-shelf quad bi-directional logic-level converter, designed to stack above the ESD protection diodes that are mounted to this board, allowing a multilayer part configuration while keeping all parts top-side.

Happy Pi Day!

This is a much improved LCD/SDCard/Keypad Interface board for the FlashForge Creator Pro 2016 (and similar) 3D Printers. It offers on-board voltage regulation, ESD Protection, proper voltage level translation, power supply decoupling, and most importantly a buffer for the MISO data line. The goal is to put an end to SDCard read problems.

The Bill-of-Materials, Schematic, and additional details are available on Thingiverse: https://www.thingiverse.com/thing:2007070.

An inexpensive through-hole remix of the Thingiverse 943091 Anti-Gravitator. http://www.thingiverse.com/thing:943091

This version is designed to be less expensive to build than the original full-size Anti-Gravitator Control Module. Most of the board was completely unused so why pay so much for a set of three boards?

Also, to make it quicker to solder together and since I have a lot more through-hole parts on-hand than surface mount, I opted to change the design to be all through-hole.

More details and pictures can be seen on my Thingiverse posting: https://www.thingiverse.com/thing:1982994.

This is a PWM Dead-Time Driver add-on board for the oneTesla v1 Musical Tesla Coil. It’s used to add a Dead-Time between the gate pulses to the IGBT driver transistors to minimize overlap and prevent premature death of the transistors.

Design files can be found at https://github.com/dewhisna/TCDeadTimeDriver.