A simple posture sensor
Here’s a simple cure for your posture and the back pain blues, a posture sensor by Wingman:
This entry was posted in hacks, sensors and tagged Attiny85, HC-SR04, ultrasonic.
The simplest distance sensors are ultrasonic or infrared sensors. I went with a SR-HC04 because it is cheap and sufficiently precise. There are no special requirements to the controller so I am using an Attiny85. A small piezo speaker provides acoustic feedback to the user. The only thing left is the power supply for which 5V are needed because of the ultrasonic sensor. You could easily use an USB port but I did not want to rely on a computer, 3 button cells deliver around 4,5V and should work for a few days.