Six weeks have passed in the blink of an eye and with only a couple more up my sleeve, this is certainly the final straight for my Honours project. After what has been a busy month with presenting my Honours thesis at Critical Animals in Newcastle and the Humanities Graduate Conference in Perth, I’m now running against the clock to finish the final device for examination on November 18th.
Based on the work I’ve done to this point – and probably more importantly, the feedback I’ve received from the mother of the participating child – I am working on a vibrating mat design for the third and final device in this case study.
Compared to the first and second device, this is a relatively simple design in terms of circuitry: a grid of vibrating motors inside the surface of the mat will be switched on/off with triggers on opposite corners, with each trigger only controlling the motors within their respective half of the mat. The reason for this is that I’m hoping to encourage some co-operative play between the child and parent/therapist. Whilst the child will be able to control one half of the mat, she might need to express desire for someone else to help her make the entire mat vibrate, adding some small level of social interaction to the process.
The motors I’m using for this device are generic replacement parts for the iPhone 3G. Aside from being a nice and small form, they’re widely available on eBay for less than AU$2 each. I grabbed 18 of them to create 2 grids of 3×3 motors.
Happily, these motors fit nicely into some electrical conduit that I picked up from a hardware store, also on the cheap. These strips will protect the spinning motor from being blocked when the foam around them is crushed from the weight of the child sitting on top.
My electrical knowledge is fairly limited, but these 3×3 grids seem to run happily on 2xAA batteries (I couldn’t find a spec sheet on the motors, but seeing as the iPhone runs on 3.7V, it’s a safe guess that 3V will do the job). I may look to some larger cell batteries, simply for duration of use, but I’m yet to decide on how these will fit inside the surface of the mat, to keep them away from the inquisitive hands of a 2 year old child.
Although fiddly, this has come together pretty quickly, so the last major hurdle is to find an upholsterer or similar to help me cover the foam mat. After speaking to the mother about material, I’ve decided that something along the lines of vinyl is the most practical approach. The exploration of texture on the second device didn’t yield much interest (it seems that fast vibration is the main attraction), so a serviceable fabric will appeal for ongoing use.