Pictured below is a motor controller we made recently for an automatic animal feeder system.
The feeder itself has two buckets on a belt which is connected to a 12VDC motor. When the motor is run, the buckets scoop up feed from a container and drop it into a trough for the animals. If the motor is left running, more and more feed will be scooped up and added to the trough, so a controller was required to ensure that each time the motor was run, the correct amount of feed was deposited in the trough reliably.
The motor needs to run for less than one minute each time, therefore a 12V programmable digital timer was chosen. The user can programme the timer to turn ON for one minute at the exact times of day that the animals are to be fed.
A switch was added to the mechanical setup which closes each time the buckets have completed one full revolution – i.e. picked up and deposited feed.
The central controller waits for the timer to turn ON. Then it turns on the motor, and keeps it running until it detects the mechanical switch closing indicating that the feed buckets have been through one rotation.
When the timer next turns ON, the switch status is ignored for the first couple of seconds (since it remains closed until the motor has moved the buckets around a bit), and then the controller keeps the motor running until the switch closes again…another feed complete. This automatic feeder will keep the animals fed the right amount at the right times of day for as long as there is feed left to be scooped up.
If you need any kind of timer or motor controller, email email@example.com with details of your requirements.