So I ended up going for a combination of idea 3 with a little of idea 2 (the beach ball). I managed to get hold of the four pressure sensors and found them very responsive. I first made a test of my idea with a breadboard, then later went to the bother of soldering up decent wires for all the pressure pads so that they would survive people sitting on them! I had some neoprene type foam so I cut a couple of squares to make the two sides of the “cushion” and stuck the pads with tape between them. I used oF with the Arduino Firmata out of curiosity as I’d not used it before – it proved quite effective, although “traditional” coding of the arduino board would not be a problem. I will continue and convert this system to wireless using an XBee, so most likely I won’t use the Firmata then, let’s see. I will be adding sound to the application as my hope and intention is to make this into a drum machine for a wheelchair user, so she can control the drums by shifting her weight.
As I’m interested in physical computing methods I hope to integrate external sensors with oF to control some 3D graphics and maybe sound as well. I’ve two, possibly three starting ideas to work with:
1. I’ve been using the 9 degrees of freedom Razor board from Sparkfun together with XBee radios to get serial data of orientation in to the PC. I’ll try to use this data to control a 3D cube – hopefully it will appear like a wooden alphabet block. Combined with this idea is the plan to create a web interface to input text that would be dynamically updated to the cube’s surface….in a future version I’d like to have many block’s (cubes) and control devices, so that a number of participants could interact at same time.
2. Second idea is to again control a 3D object, in this case a balloon or beach ball that is floating in space. A participant blows through a tube which has some “wind” sensor (not sure where to get this from at short notice!) measuring the power of puff (blowing). Idea is to have two of these devices so that a sort of simple “pong” type game could be played, where each player is trying to blow the ball off the other end of the screen.
3. Finally I was interested to use the pressure sensors with the arduino firmata and oF. I’m hopefully getting four of these today, so I’ll try out making some sort of pressure mat (cushion) for controlling something – most likely sound and visuals. Idea would be that by shifting your weight on the cushion you can control the media without using hands or other body movement. This is directly related to research work I am carrying out at the moment with physically disabled people.
Link to project files, including Mac apps and multi-platform source code: