Playing around with gravity:
A basic piece exploring interaction with gravity. It is (again) half a ping pong ball. On the rim there is a red dot, which always stays up. You can turn it as you want – the red dot will go up again. Video after the click.
It is much easier to see it in real:
Basically it is a very small “physics engine” which tries to hold the dot up. Which side is up is determined by an accelerometer. The measured gravity creates a force which drags on the dot and by that it is always dragged upwards. By applying the right force you can even try to toss the dot in circles.‚ The whole project does nothing real useful – but using accelerometers is a nice way to interact with electronics objects
The internal construction consists of 12 Micro SideLeds (simliar to but completely independent of the Led Lighthouse), arranged in a circular shape, connected to an ATmega168 controller. There was nothing fancy used like charlieplexing the LEDs. The ATmega168AU has enough pins and a extremely small form factor. An ADXL322 is used as accelerometer:
The whole project was done again using only SMT parts. Mostly due to availability (e.g ADXL322), size (e.g. getting a whole ATmega168 in an ping pong ball) or aesthetics:
The source code can be found in the Gravitron source archive. Perhaps it can help you with anything – perhaps not. Hopefully it does not hurt anybody or destroy anything. If it does – I am not responsible.