After my last meeting with the CMTF team I was able to get my hands on some of the electronic components that will dictate the dimensions of the units. The first picture shows the circuit board used for the motion capture sensor and the one used for the data collecting unit. The sizes are pretty fixed by now bit I had the chance to move some components on the capture sensor board.
This is the rough size of the capture sensor, looks pretty small the trick is that on top of it here is a 3 axis cubic accelerometer that measures around 20x20x20mm.
Some new sketches of the sensor now considering the right sizes and proportions. One of the directions looks really promising, simple shapes and construction... more to come on it.