I need some guidance on how to attack a design I have in mind. Any help would be greatly appreaciated.
I am trying to connect three of the “chinese” digital calipers to computer for data logging. The caliper has a “USB-ish” port on it with Vsupply, Ground, Clock and Data. The caliper sends a 21-bit value over the data line roughly 150 times per second. (Details can be found here: http://www.shumatech.com/web/21bit_protocol?page=0,1)
Basically I need to continously read three of such scales and send the data to the PC via BT serial modem (that part is already done with). The thing I’m not too sure about is the reading of the scales. If I were using just one, I’d simply use the clock line to trigger port interrupt and then read the value at the data port (with some sanity checks), but I’m not certain that I can pull that off with more than one scale.
Again, any help would be greatly appreciated.
P.S. For those curious what the thing is for: I often find myself making (manually) more than one copy of a part on my mini mill. I’m trying to make an “do what I just did” CNC conroller for it. I.e. the computer would record my movements and the replay them as needed…