I have a boot dryer that I use everyday. It is plugged into an outlet by my door that is controlled with a light switch. This works well for the most part but since the boot dryer does not have a power switch that means that when the outlet is on the boot dryer is on. That outlet is also used to turn on a lamp that lights my apartment so for the most part when I am home the light is on and therefor the boot dryer is on. I wanted to change that so I came up with the below circuit that uses a ATtiny10 and a SSR to turn off the boot dryer after a programed amount of time.
The circuit is simple and uses a capacitive dropper as the power supply for the ATtiny10. Resistors R3 and R5 are used to set the time from 30 minutes to 3 hours since I also plan to apply this circuit to my hot glue gun and the cheap soldering iron I use to install threaded metal inserts into 3D printed projects. All the components I used for this project where what I had on hand from previous projects or had salvaged. Installation is easy, cut the cord anywhere convenient and solder the cord to the PCB. The PCB is housed in a 3D printed enclosure to ensure no part of the circuit is exposed and also provides some strain relief to the cord.
All design files are available in a GitHub repository.
SD Perry 