29-30 July: Switches

We programmed the limit switches with the linear actuator. When the linear actuator touches the limit switch, it will immediately stop.

We also programmed the reed switch to work with the stepper motor as well.

3-4 Aug: More Prints and Ultrasound Sensor 

We printed the tray with the feature of swapping out different modules. 

We also redo our stepper motor holder as we would like to invert the stepper motor instead.

As we are using the ultrasound sensor to detect the presence of the test tube, the dectected distance would be around 4cm. The ultrasound will travel this distance to and fro in microseconds. As CODESYS does not measure time in microseconds, we had to programme the ultrasound using arduino and connect the arduino to the raspberry pi with a voltage level shifter.