Fused System Testing

Once we had the mechanical, electrical, and software systems built, we started on the most exciting part --- fused system testing. However, we ran into issues right from the start. After powering up the whole system and sending out drink orders, nothing happened. This result took our excitement on seeing the whole system in action slightly away. We quickly gathered and started to look for the problem.

Trouble Shooting Relays

Since we are using optical relays as "switches" to turn the pumps and valves on and off while separating the power circuit from the Arduino control unit, we were suspecting that the relays weren't being turned on and off properly. Therefore, we disconnected the relay unit and made a 4-LED circuit on a breadboard with each LED representing the one valve-pump circuit in our system. Then, we connected the LED circuit with the relay unit and the Arduino in the same fashion as the valve-pump circuit. A testing copy of the Arduino code was implemented in the same logic as the actual hardware code in order to control the relays. When the Arduino sent the "set_relay" command, the corresponding relay turned on and the appropriate LED lighted up. We repeated this test couple times to make sure we were indeed controlling the relay correctly and the relays were indeed functioning as they should. After the relay testing, we concluded that the relay unit was working properly. Since it is evident that there was no power delivered to the pumps and valves, another place where things could go wrong was the power adapters. Thus, we quickly turned our attentions to those power adapters we got off Amazon.

Trouble Shooting Power Adapters

Frankly, those power adapters we got off Amazon felt cheaply made. When we were opening the packages, we found out that one of them seemed to be opened already. We suspected that it might be a return from another customer but we didn't really wonder why it was the case. We just connected it to our circuit. After a bit of probing with the multimeter, we found out that the returned adapter was defective and it was then we realized exactly why it was returned. Then, we proceeded to examine the rest of the adapters and realized that they were of low qualities. The connectors on the adapters are very sensitive to positions. If they were squeezed into a small place, they could get disconnected. Since the power adapters were really hard to work with, we expanded our budget on them and bought higher quality ones. After the replacements, our system was able to dispense liquids with the basic testing codes.