For this project, the Electrical Team focused on finding a way to power all four peristaltic pumps and interface the pumps with the Arduino.
Powering the Pumps
12V Power Converter & Relays
The peristaltic pumps that we used required 12V of power to run. We chose to use a 12V power converter to run the power from the wall to the pumps. We were initially worried about powering all four pumps at the same time, but we realized that, since we were turning the pumps on one-by-one, all four of the pumps could pull from the 12V.
In order to interface the pumps with the Arduino, we utilized an 8-relay power shield. We used four of these relays. Once the Arduino received the pump and amount information, it would activate the respective relay using 5V of power, which would then close the circuit to power the pump with 12V. Using the Arduino, we can continuously send 5V to the relay to keep the circuit closed and pumps open if necessary. This allowed us to decide how long to power the relay to dispense the proper amount of liquid. Furthermore, based on which PWM digital pin we supply power to on the Arduino, we can activate each of the four pumps individually.
Hand-drawn circuit diagram for a single relay
Hand-drawn circuit diagram of the entire electrical system