by SquareBoot @instructables
Hi, with this instructable I want to show you an open source pendulum that can compute and process the measured oscillation period to find the gravitational acceleration of the earth (~9,8 m/s²)! It's the most powerful of all, discover it!
The project is based on the Arduino platform, but it contains a DIY PCB. The structure is made from an AutoCAD 2016 drawing that has been laser cutted. If you haven't got a ball, there's a 3D-printed ball file in my site.
To check the position of the ball I used three infrared break beam sensors from Sparkfun (tutorial): they are really sensitive but they can't work with a lot of light (if they don't work anything, turn off the lights in your room).
You can download all the files and view them using the preview function in my site.