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Tag Archives: ATtiny85

DIY Buck-Boost converter

Posted on October 9, 2016 by R-B Leave a comment

A buck-boost (also known as step-down and step-up) converter is a type of DC-to-DC converter that combines the principles of the buck and boost switched mode power supplies in a single circuit. What this means is the input voltage could be either higher or lower than the desired output voltage. The Buck-boost converter is very useful in battery-powered systems, where the battery voltage can vary quite a bit depending upon its charge condition and usage, to derive a stable DC supply for an electronics circuit.

DIY buck-boost converter

GreatScott‘s new Youtube video tutorial explains the basics of Buck-Boost converters and shows how to build a 12V Buck-Boost converter using discrete components like MOSFETs, inductors, and Opamp. The square wave of varying duty cycle, which is a key component of any buck and boost converter, is generated by the ATtiny85 MCU. The output of this buck-boost converter is inverted, and therefore, an Opamp circuit is required to correct the polarity of the output for the feedback signal that goes back to the MCU. Based on the magnitude of the feedback voltage, the ATtiny85 controls the duty cycle of the square wave to stabilize the output voltage.

ATtiny keychain game console

Posted on April 10, 2016 by R-B Leave a comment

This tiny keychain game console is pretty neat and is based on ATtiny85 and and a SSD1306-driven OLED screen. The author has also shared the code for the UFO Escape game for this console.

ATTiny85 game console

I finally had some free time to make something fun and decided to write a new game for the Attiny85 ssd1306 keychain. I reused the sleep, display and interrupts code from the “Breakout” game I created a while ago.

This time I wanted a more addictive game. The game had to be playable using just the two buttons. I thought a racing game might be a good choice but the landscape screen is more suitable for a side-scroller. So I settled for an obstacle avoiding side scroller. Similar games include the recent Flappy Bird, Nyan Cat and many variations of the Helicopter game.

Demo video.

Musical holiday card with a CD case

Posted on January 8, 2015 by R-B One comment

Dmitry Griberg’s musical holiday card project is really cool and plays a full song in full fidelity from an SD card. The project uses Attiny85 microcontroller and a 4-MOSFET amplifier circuit, both powered from a LiPo battery. The complete circuit is enclosed inside a CD case, and a simple flexible metal strip is used to make a contact sensor that will activate the player when the CD case is opened. The songs are saved on the SD card as WAV files with 32KHz sampling rate and 8-bit samples.

Musical holiday card

Here is a demo video of this:

Remote-controlled biped robot using Attiny85

Posted on October 22, 2014 by R-B Leave a comment

Max’s remote-controlled biped robot uses four servo motors for its legs and feet to go forward and backward. The Attiny85 microcontroller is used as its brain which receives and follows the motion commands sent from an infrared TV remote.

Attiny85 biped robot

nrf24l01+ RF module and ATtiny85

Posted on February 17, 2014 by R-B One comment

Ralph Doncaster writes,

Nrf24l01+ modules are a cheap and low-power option for MCU wireless communication. Libraries are available for Arduino, and for arduino compatible MCUs like the ATTiny85. Controlling the nrf modules usually requires power plus 5 pins – CE, CSN, SCK, MOSI, & MISO. With pin-limited MCUs like the ATtiny85, 5 pins is a lot to tie up. On something like the Digispark, with PB3 and PB4 hard-wired to USB+ and USB-, using the nrf24l01+ modules might seem impossible. Another issue is that although the nrf inputs are 5v tolerant, Vcc must be between 1.9 and 3.6V. I’ve designed a simple solution to provide 3V power as well as control the modules with just 3 of the pins on the ATtiny85.

Controlling Nrf24l01+ RF module with 3 I/O pins

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