Fabricating Custom Displays For A Commercial Coffee Roaster

custom-display-panel-for-a-coffee-roaster

Roasting the perfect coffee bean is an art form. But even the most talented of roasters can use a little feedback on what’s going on with their equipment. [Ludzinc] recently helped out a friend of his by building this set of 7-segment displays to show what’s happening with this coffee roaster.

The yellow modules hiding underneath the display panel are responsible for setting the speed of the hot air blower and the rate at which the drum turns. They’re adjustable using some trimpots, but it sounds like the stock machine doesn’t give any type of speed feedback other than direct observation.

The solution was to patch into those speed controllers using 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 each readout, the firmware can be custom tuned to suit the operator’s needs.

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

Add Speed Control To A DIY CNC Machine

adding-speed-control-to-diy-cnc

[Jesse Merritt] bought a manual speed controller for his router. It’s used in the CNC mill he build and he figured, why not add the ability for the computer to control the speed.

The speed controller is a $20 unit from Harbor Freight. It comes with an On/Off switch and knob which adjusts the power going to the router. [Jesse] pulled off the knob and milled a gear which takes its place. The second gear is attached to the horn of a hobby servo mounted on the side of the speed controller. The video after the break demonstrates an Arduino driving the servo based on a potentiometer input as well as commands from the CNC controller board he’s using.

Design files for the gears and the Arduino code which drives the servo is available from his Github repository.

Continue reading “Add Speed Control To A DIY CNC Machine”