Displacement : Encoder
The encoder and the LDR Sensors and the schmitt-trigger( see below ) used to be able to interpret the square waves. The sensors produce a voltage between 0-5V. Since we're only interested if the hole has passed or not, we'll use the properties of a schmitt-trigger to produce a digital output.
Force Applied : Work-Around : Op-Amp
Since the short-circuit happened ( we still don't know what caused it ), our load cell didn't produce the same voltages anymore. Before the short-circuit we perceived voltages between 0-4V depending on the force. Now it fluctuates in the range of milliVolts. To get a reading we can work with, we had to improvise and so we thought of amplifying the signal.
To use an Op-Amp we needed a power supply. The power supply we used didn't possess ground though, so we had to make one.
Due to the numerous problems and work-arounds we had to conceive, we were unable to create a board for our project.Instead, we had to rely on a bread-board and the demo-board.
Two connections were used, namely the USB connection to program the PIC and the USB to Serial connector to transmit data from the PIC to the pc(picture to the right).