Activating a PC with a knock and an ATtiny

A Maker by the name of Joonas has designed a knock sensor to activate his PC. According to the HackADay crew, the entire project cost Joonas a grand total of $10 and is built around Atmel’s ATtiny45 MCU which is tasked with emulating a PS/2 device.


“This takes advantage of his computer’s ability to boot upon receiving PS/2 input,” HackADay’s John Marsh explained. “The build uses a Piezo buzzer and a 1M Ohm resistor as a knock sensor exactly as the official Arduino tutorial demonstrates, [plus] one of those PS/2-to-USB adapters that are most likely lurking in the back corner of every drawer in your office.”

In addition, says Marsh, AVRweb was used to disable the 8X clock divider so there would be sufficient clock cycles for PS/2 communication. Joonas subsequently loaded some test code (final version posted to Github) to ensure the vibrations were being detected correctly.

Readers of Bits & Pieces may also want to check out a recent article about a Halloween Knock Box powered by Atmel’s versatile ATtiny45 (or 85) microcontroller (MCU).

The box is fairly easy to put together, as basic components include an MCU, a piezo element (amplifier) for the knock sensor and a motor to provide the knocking feedback.

2 thoughts on “Activating a PC with a knock and an ATtiny

  1. Pingback: Atmel’s tinyAVR is a Maker favorite | Bits & Pieces from the Embedded Design World

  2. Pingback: Video: Hacking a Valentine with the ATtiny85 | Bits & Pieces from the Embedded Design World

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s