I wanted a filament dryer box and found a YouTube video showing control circuits for temperature and timer.  I drew up the 2 boxes to be used on my dryer box.  The modules are sold on Amazon and eBay and uses a heated bed from an older 3-D printer I was not using anymore.  Each of the modules had switch buttons and I made button actuators that extended outside the box tops for setup programing.    The circuit pad is for the timer module as pins extend below the circuit board, just glue it under the module.

the timer module is a JZ-801 and the temp module is a W1209 you can google them and download a manual for programing, and the video shows a wiring diagram.

Here is the YouTube video about the control circuits