Hardware — Standing on the shoulders of giants

A display that stays visible without power: Waveshare e-Paper display , paired with todos

this Waveshare Environment Sensor HAT for Raspberry Pi . Python collects sensor readings hourly and saves them to MongoDB. A Node.js backend exposes an API, and the frontend displays the data using ECharts . The server and database are far away, so loading the readings can take a little time. Visit page 。

Take a photo with Raspberry Pi . I wanted to try building a face-recognition door opener. The v3 camera finally supports autofocus, and its 12-megapixel sensor offers plenty of detail.

Mijia Temperature and Humidity Monitor Pro. A similar device could be built using a Waveshare segmented e-Paper display , a Waveshare temperature and humidity sensor, a Raspberry Pi Zero 2 W and a 3D-modeled, 3D-printed case, plus a companion app.

A Pomodoro timer I made. One LED lights up each minute: focus for 3 × 8 minutes, then rest for 1–8 minutes. More boards could make traffic lights. I wasn’t using Git, and lost the code…

Pico WH

A stepper motor controller built with a Raspberry Pi Pico WH, an MKS TMC2209 v2 driver, a 17HS8401 stepper motor and a 0–30 V, 0–10 A adjustable power supply.

Raspberry Pi Pico WH

With built-in wireless connectivity and pre-soldered headers, this board sends control signals to the motor driver.

17HS8401 stepper motor

Timing pulleys, a belt and 3D-printed supports form a belt drive mechanism.

MKS TMC2209 v2

Receives control signals from the Pico WH and drives the stepper motor.

Micro:bit

Connect a soil moisture sensor and a small motor-driven pump to water plants automatically. I’d like to try building one.

A self-balancing robot, controlled over micro:bit Bluetooth to move forward, backward and turn, with a companion app and a controller.
I think its balancing system uses an STM32, an accelerometer and servo motors.
I later discovered that even a single wheel can balance itself. There are already products that do this. Impressive.