Our dog Charlie is getting older and her stomach can get upset if she doesn’t eat at the same time every day. Since we are sometimes away at her dinner time, I created this automatic dog feeder.
The feeder release mechanism is a solenoid taken from an old cassette tape machine plus a normally open microswitch. The feeder door is held closed until the solenoid engages and then the dog food can drop into Charlie’s bowl. Power for the solenoid comes from an old phone charger that’s plugged into a TP-Link smart plug. I set up a daily timer to turn on the smart plug at dinner time each day and then turn it off one minute later. Note that the solenoid only needs to engage for a moment to release the door, and then the microswitch cuts power when the door drops open, so the solenoid isn’t continuously powered, even for a minute. The TP-Link smart plug is also Alexa controlled, so we can also say “Feed Charlie” and an Alexa routine will open the feeder – it’s fun to demonstrate to friends and visitors!