I see my project breaking down into three components. In order of priority, they are:
The first piece I would like to build is a “probe,” the piece that actually comes in contact with human skin. I imagine this will be a rod with a vibration motor and a cloth covering, which is then wired up to control vibration speed and rhythm.
The second piece is the mechanism for controlling the location of the probe on the arm. Ideally I would like the probe to move on three axes, similar to a CNC machine, but two axes (along the arm and down onto the arm) are more likely. A pressure sensor would be helpful here to standardize sensation.
The third piece is the frame. Initially I was conceiving this as a wearable piece, but I am not sure how large and heavy the placement piece will be. If possible, I’d like to build a frame out of PVC piping to hold the device on an arm.