roasting the perfect coffee bean is an art form. however even the most skilled of roasters can utilize a bit comments on what’s going on with their equipment. [Ludzinc] just recently assisted out a buddy of his by building this set of 7-segment screens to show what’s happening with this coffee roaster.

The yellow modules hiding beneath the screen panel are accountable for setting the speed of the hot air blower as well as the rate at which the drum turns. They’re adjustable utilizing some trimpots, however it seems like the stock machine doesn’t provide any type of type of speed comments other than direct observation.

The solution was to patch into those speed controllers utilizing the ADC of a pic chip. They each output 0-10V, which [Ludzinc] measures via a voltage divider. After the speed is quantified the microcontroller outputs to one of the displays. since there’s a different chip for every readout, the firmware can be custom tuned to fit the operator’s needs.

Keep this in mind if you’re still planning to develop that coffee roaster out of a washing machine.