A peristaltic pump was chosen to drain and fill the water tank. Peristaltic pumps are unique in the
fact that they can run in both directions and also hold the water level if stopped. A flexible
silicon line runs inside of the pump, while rollers push fluid by pinching off the line. The PWM
in Block 4 controls the rate at which the motor controlling the pump moves. The water pump in
turn controls the water level, or process, in Block 6 by pulling water from a water reservoir
located in the suitcase. The principle of how a peristaltic pump works is shown in Figure 7. The
pump chosen is the Boxer 15002 DC motor driven pump, purchased from Clark Solutions for
$171.23. This is also shown in Figure 7. This has a maximum flow rate of 529.2 ml/min which
should have been able to fill the 507 mL water tube in about 57 seconds. This datasheet for the
15002 is in Appendix A.
Transfer function for peristaltic pump: FR = 16(ml/min*V)Vin (flow rate = 16*voltage in)