Mcu category

ATtiny85 Function Generator

David Johnson-Davies build a tiny function generator based on ATtiny85 microcontroller. He writes:

This article describes a simple function generator based on an ATtiny85. It can generate triangle, sawtooth, square, and rectangular waves, a pulse train, and noise. The frequency can be adjusted using a rotary encoder between 1Hz and 5kHz in steps of 1Hz, and the selected waveform and frequency is displayed on an OLED display.

This project really puts the ATtiny85 through its paces; it’s generating 8-bit samples at a 16kHz sampling rate, decoding the rotary encoder, switching between waveforms, and updating the OLED display via I2C.

ATtiny85 Function Generator – [Link]

Infrared repeater using AVR mcu

Madis Kaal @ designed a infrared repeater based on ATMEL AVR + TSOP1738 infrared receiver. He writes:

I built this MCU based infrared repeater to allow me to control my A/V equipment that is behind a wall. The system is very simple.

Power is supplied to CON1 from a cheap Alcatel phone charger that outputs stabilized 12V, passes through reverse voltage protection diode to IC1 that outputs 5V VCC. Atmel AVR microcontroller runs from 4MHz ceramic resonator Y1, C3+R1 form a reset circuit. Infrared detector (TSOP1738 in my case) is connected to INT0 input, C1+R2 are for detector power filtering.

Infrared repeater using AVR mcu – [Link]

ATtiny85 runs at 0.000011574Hz clock

What is the lowest possible clock frequency at which a microcontroller can still do useful work? Here’s a little project that attempts to explore this weird question. by @

ATtiny85 runs at 0.000011574Hz clock – [Link]


Writing to flash and EEPROM on the tinyAVR 1-series

Update your tinyAVR code to access memories when using 1-series tinyAVRs. Link here (PDF)

On tinyAVR® 1-series devices, access to Flash memory and EEPROM has been changed from that on previous tinyAVR devices. This means that existing code for writing to Flash and EEPROM on older devices must be modified in order to function properly on tinyAVR 1-series devices. This application note describes what has changed and how to adapt code to these changes.

Writing to flash and EEPROM on the tinyAVR 1-series – [Link]

Sino: bit – Changing Programming for Kids All Over the World

Creating projects with Arduino can be challenging for kids, this may cause children to lose interest in electronics and DIY projects. The most complicated part is usually the connections required to use a sensor, led matrix or other devices that can be connected to the Arduino (or other microcontrollers). Since all these devices are different and have different types of connections which need to be made in a certain way, electronic projects may get boring or too complicated for a kid to learn. If the objective is to teach a kid how to code without the extra complication of cables, then the Sino: bit is the perfect choice.

Sino: bit is a microcontroller designed for teaching computer education in China created by Naomi Wu a DIY enthusiast. It is based on Calliope mini and can be programmed with Arduino IDE. It includes a 12×12 LED matrix, accelerometer, magnetometer, Bluetooth, buttons, a micro USB for programming, temperature sensor and a JST 3v battery connector. The battery connector was included to run projects without the need to be connected to the computer at all times.

Usually, when learning how to program kids are taught “hello world” which is a simple code that displays the same message. The 12x 12 LED matrix has that size not only to allow kids to play with a huge number of LEDs, but also to allow kids from every nation to do and understand their hello world. This was a problem because Chinese, Japanese, Hindi and other languages contain characters that cannot be displayed in a small matrix.

It’s the first to obtain the OSHWA (open source hardware association) certification in China which is an association in charge of making the task of identifying and marketing open source hardware products clearer and more transparent.

With a simple installation procedure, codes such as blink can start to work, and children all over the world would be able to experience “hello world” in their own language which will bring opportunities and open doors for non-English speaking kids. With all the sensors and options that it offers projects can be as simple as playing with LEDs and as complex as communicating with an external app to send information about the sensors. With the use of Sino: bit not only programming will be more inclusive, but also more code focused because instead of spending a lot of time thinking about connections kids can test their projects faster and with less room for errors.


MATRIX Voice: Open-Source Voice Recognition

MATRIX Voice is a”Voice Recognition” development board, designed for the Raspberry Pi or Stand-alone with ESP32 (WiFi/BT/MCU)

MATRIX Voice is an open-source VOICE RECOGNITION platform consisting of a 3.14-inches in diameter dev board, with a radial array of 7 MEMS microphones connected to a Xilinx Spartan6 FPGA & 64 Mbit SDRAM with 18 RGBW LED’s & 64 GPIO pins. Providing developers the opportunity to integrate custom voice & hardware-accelerated machine learning technology right onto the silicon. An ESP32 Wi-Fi / BT enabled 32 bit microcontroller version is available. It’s for makers, industrial and home IoT engineers.

The project is already funded on and shipping begins next week.

Flight controller unit evaluation board for drones

The STEVAL-FCU001V1 board from ST is designed to support quadcopter drone designers with the latest solutions for motor control, sensors and and microcontroller.

A complete sample FW project allows the designer to begin flying small and medium size quadcopters (with brushed or brushless DC motors) immediately and evaluate the performance of the IMU sensors under real flight conditions. The FCU can be controlled by a standard external remote controller (PWM input interface) or by a smartphone or tablet through the Bluetooth low energy module present on board (CE, FCC, ARIB, BQE certified). Magnetometer and pressure sensors are also embedded to support 3D navigation applications. SWD, I²C and USART connectors are available for FW development and debugging, and to support additional external sensors or RF modules.

Key Features

  • Compact Flight Controller Unit evaluation board complete with sample firmware to a small and medium size quadcopter
  • Lipo 1-cell battery charger on-board
  • Possibility to drive directly 4 DC brushed motors through low voltage on-board MOSFET or alternatively use external ESC for DC brushless motor configuration
  • Main components:
    • STM32F401 – 32-bit MCU with ARM® Cortex®
    • LSM6DSL – iNEMO intertial module: 3D accelerometer and 3D gyroscope
    • LIS2MDL – High performance 3D Magnetometer
    • LPS22HD – MEMS pressure sensor: 260-1260hPa absolute digital output barometer
    • SPBTLE-RF – Very low power module for Bluetooth Smart v4.1
    • STL6N3LLH6 – N-channel 30 V, 6 A STripFET H6 Power MOSFET
    • STC4054 – 800 mA Standalone linear Li-Ion battery charger
  • RoHS compliant

Tomu – An ARM board which fits inside your USB connector

Tomu is a programmable computer that is so small that can fit entirely inside a computer’s USB port. It sticks out just a little bit, enough to allow you to press one of the two buttons on it’sy side. It also have two LED lights, to let you know what I’m up to. The project is coming soon on


  • 25 MHz ARM Cortex M0+ CPU
  • Two LEDs
  • Two capacitive-touch buttons
  • 8 kilobytes of RAM
  • 64 kilobytes of flash
  • Full and Low Speed USB

ESP32-PICO-KIT Development Board

ESP32-PICO-KIT V3 is a mini development board based on the ESP32-PICO-D4 SIP module produced by Espressif. All the IO signals and system power on ESP32-PICO-D4 are led out through two standard 20 pin x 0.1″ pitch headers on both sides for easy interfacing. The development board integrates a USB-UART Bridge circuit, allowing the developers to connect the development board to a PC’s USB port for downloads and debugging. The board is available for $10 here.


  • 3.3V power regulator – AMS1117-3.3V
  • USB-TTL serial Bridge – CP2102
  • Auto reset circuit, arduino IDE compatible.
  • On Board ESP32 PICO IC and antenna
  • EN and Boot buttons, on board power indicator LED.

LED Heart Keychain

@ build a heart shaped keychain that flashes 2 LED with the touch of your finger! Source files are available on github.

This one is a very simple but cool project, something that I would recommend to anyone who is interested into DIY electronics, gadgets and learning new stuff in general. It is definitely one of those projects that don’t require too much time but you can learn a lot by making it and also earn a lot of credit by sharing it with your friends and family.

LED Heart Keychain – [Link]