Raspberry Pi CAN-bus HAT for the Omzlo IoT platform

From Omzlo Electronics:


A Raspberry Pi CAN-bus HAT for the Omzlo IoT platform

In a previous blog post, we described “SKWARE” our revised Arduino-compatible IoT modules. These nodes are designed to be connected together in a daisy-chain fashion with a single cable that brings both DC power and CAN-bus networking. The voltage transported in the cables is not 5V (or 3.3V) but rather 12V or 24V to work more comfortably over long distances, potentially reaching 300 meters (1000 feet). You can think of it as a poor-man’s PoE.


This network of connected nodes is designed to be monitored and controlled by a “master node”, which injects the necessary 12V/24V DC, provides node management services and a web interface for network administration. While the IoT nodes are based on an Arduino-style microcontroller, the “master node” requires a bit more power. In this context, the ubiquitous Raspberry Pi with its GPIO header seems like an ideal candidate for that role and we decided to see if we could build a “master node” by augmenting a Raspberry Pi with an appropriate add-on board. These add-on boards are called “HATs” (for “Hardware Attached on Top”) and we called our first prototype the “Pi Master HAT”.


The drawing below illustrates the general structure of our network. A Raspberry Pi equipped with our “Pi Master HAT” controls a network of 2 (or more) daisy-chained nodes, like the SKWARE.


Raspberry Pi CAN-bus HAT for the Omzlo IoT platform

Help gamaral’s Cancer Treatment

If you’ve enjoyed Guillermo Amaral’s electronics projects such as the Canon DSLR WiFi RemoteRaspberry Pi PSUUARTMatic 3000+, Keypad Submodule and many more, then please consider giving to his cancer treatment fund:

Gamaral’s Cancer Treatment

I’ve unfortunately had to flip the bill for my two past surgeries and my on going cancer treatment… and as you can imagine, I’m running out of cash.

If you like my content and/or have found my published projects interesting or useful, please consider sending me some spare change and I’ll be ever so grateful.

Here are couple great project videos by Guillermo on YouTube:

Help gamaral’s Cancer Treatment

Wemos D1 Mini Breakout for an ST7735 Display

Radomir Dopieralski has created this breakout board to make it easier to slap a popular ST7735 module on top of a Wemos D1 Mini:


D1 Mini Breakout for an ST7735 Display

There is a number of options you have for display shields for the D1 Mini: there is the nice OLED shield, there is a shield with a single WS1228B neopixel, there is the #D1 Mini Matrix Shield I’m still working on. But there is no high-resolution color display you could just slap on it. This “shield” doesn’t really deserve the name, it’s just a simple breakout board that connects the ST7735 display module with the SPI pins of the D1 Mini, and adds a trim pot for brightness control.


To save some pins, the CS pin is hardwired to GND, and the A0 pin is connected to MISO. That means you can’t connect other SPI devices while this is in, but that’s a rare enough case for me to care. It uses four GPIOs total, from GPIO12 to GPIO15. The backlight is connected to the 5V supply (to not strain the on-board 3V3 regulator) through a trim pot, so you can adjust brightness.

I used alternating holes for the module’s header, so that with some luck you should be able to plug in the module directly, without soldering a female pin header there — that should also save some space.

Wemos D1 Mini Breakout for an ST7735 Display

Asset Tracker

Kris Winer designed this is a small 4-layer PCB for remote logging of absolute position and orientation:


Asset Tracker

STM32L433-based board with CAM M8Q concurrent GNSS, EM7180 + MPU9250 + MS5637 for absolute orientation, and an ESP8285 for wifi connectivity.

The absolute orientation engine uses the MPU9250 accel/gyro/magnetometer IMU sensor plus the MS5637 barometer as slaves to an EM7180 motion co-processor that sends quaternions and drift-stabilized altitude to the host via I2C.

PeskyProducts has shared the board on OSH Park:



Order from OSH Park

Asset Tracker

STM32L4 Sensor Tile

From Kris Winer on Hackaday.io:


STM32L4 Sensor Tile

Small, connected device for smelling and hearing in any environment.

This is a 20 mm x 20 mm four-layer pcb tile full of interesting sensors (ICS43434 I2S Digital Microphone, MPU6500 acclerometer/gyro, BME280 pressure/temperature/humidity, and CCS811 air quality) with a Rigado BMD-350 UART BLE bridge for sending data to a smart phone all managed by a STM32L432 host MCU.

The STM32L432 is programmed using the Arduino IDE via the USB connector and serial data can be displayed on the serial monitor to verify performance and proper function, etc. But it is intended to be powered by a small 150 mAH LiPo battery for wireless sensing applications. The STM32L4 is a very low power MCU and with proper sensor and radio management it is possible to get the average power usage down to the ~100uA level, meaning a 150 mAH LiPo battery can run the device for two months on a charge.

A library for it is available on GitHub:


A collection of sketches to run the STM32L432-based (20 mm x 20 mm) sensor tile with an MPU6500 accel/gyro, ICS43434 I2S digital microphone, BME280 temperature/pressure/humidity sensor, and CCS811 air quality sensor. The sensor tile has an on-board MAX1555 LiPo battery charger, an on/off switch, and a Rigado BMD-350 nRF52 BLE module.




STM32L4 Sensor Tile

Automated Pool Controller

Jerad Jacob designed this board to monitor and control a swimming pool:



Cloud-based pump speed, solar collector controls, and temperature monitoring for your pool with SmartThings and Alexa integration

Timer Control of a Hayward Tristar VS Pump and Hayward GL-235 Solar Pool Controller


osmosis has shared the project on OSH Park:

Pool Controller v2.2

Order from OSH Park

Automated Pool Controller

Tindie Seller Interview: Alex Albino

interviewed Alex Albino of Femtoduino for the Tindie blog:

Alex Albino, of the Femtoduino Store, is one of the original sellers on Tindie, with his store officially listed as opening on November 26, 2012. During this time, he’s sold well over 300 of his custom boards, and I was glad to catch up to him to ask a few questions.

Albino, who works as a software and web developer, first got into electronics after his NES was fried in a thunderstorm in junior high, and he got to take it apart. Eventually his interests led him to the Arduino and Fabio Varesano’s work, and multiple hardware platforms over the years.

Albino’s store started with him asking Fabio Varesano if he could sell Femtoduino boards, which have the same outputs as an Arduino Uno in the size of one’s thumb. Since Varesano wasn’t interested in selling them himself, he generously gave Albino permission to run with this design. Albino then went to work assembling and selling these boards, and even made sure to give a portion of the money he made—though he didn’t have to—back to Varesano to promote his open source work.


Of course, these tiny Arduino clones are still for sale, but Albino sells several other items, including the FemtoBeacon wireless IMU (inertial measurement unit) sensor. He even notes his store theme as providing the smallest open source IMU sensors in the world. You can see one in the image above next to a U.S. dime—quite small indeed. He hopes to grow the Femtobeacon business into a full-time job in the future.

Naturally, Albino has bought from other Tindarians in the past, which he says is always fun. He also notes that, “If you sell anything on Tindie, make sure to package carefully, take decent photos, and include videos of stuff in action!” As such, here’s a video of the tiny Femtoduino in action:

Tindie Seller Interview: Alex Albino