I need to build a device that opens a chicken coop door.
The idea is quite simple, a motor connected to an axle that pulls a string up just like a wench. It would be activated by a relay timer setting it to open at 2 different times of the day (Morning and night) for a specific amount of time, enough to open and close the door. The problem I'm having is how to make it close...
I have a 6v electric motor that works just fine for the job and inverting the polarities can also close it, but I wanted to make the polarities automatically invert somehow, after each activation, in the morning it open, and inverts the polarities making it close at night and so on. I could attach a string to the door and use a polarity inversion switch, the string pull the switch when stretched enough, but that seems way too trashy haha. Having a linear actuator is not an option where I live, and I thought about using a spring to close, but I don't want to make a possible guillotine.