After days of dancing, testing and occasionally playing all of a sudden the blue chute stopped working. Just at the end of the day one of the motors got a glitch, a very strange one. The controller still communicated with the main computer and everything seemed fine, but the motor acted very strange, it turned clockwise and counter clockwise terrifyingly vigorous. (not in a dangerous way. We were just afraid one of the motors would brake itself.)
To get into detail:
We immediately inspected the motors and controller. Step by step we eliminated every possible thing that could have been damaged or broken. The wiring was fine, the xBee worked as it should and the Arduino didn’t send faulty data. After measuring some current flows, the measurements didn’t show any values to be concerned. Wire after wire we’ve got down to what the troublemaker was.
In the top of the suspension of the blue chute there is a simple little sensor which would trigger if a small ring on the wire pulling the blue chute up would touch it. This trigger was a simple INPUT_PULLUP on the Arduino. As the ring would touch two small wires, it would complete a circuit from an Arduino pin to a ground pin and thus sending a ‘stop & turn’ signal. One of the leads in this sensor suddenly got very very sensitive, just by touching the connector with something metal or even a finger would make the trigger go crazy. We got the controller box down and tested it thoroughly. After almost three hours of troubleshooting and reconfiguring the Arduino and it’s code we got it working again. We didn’t think analog input ports were the way to go, but in this situation it is. The ‘pull down’ on the analog port is much more stable then what the digital input gave us as reading, totally unexpected. Arduino may be your best friend in a lot of situations but when its not, it can be your worst enemy.
This morning we configured the small pc, that will run the whole installation when it’s presented, and all went well. As we dutch say: “That gives the citizen courage” 🙂