March 6, 2022
Arduino DIY roaster control
The arduino control article is very good.
It discusses general concepts like PWM for DC motors versus
SCR/Triac control for AC motors versus
using an SSR for heater control.
A powerful enough light dimmer will do the job to control a blower motor.
Note that the fellow who did this with his SR540 burned out the blower motor.
Source code
After reading the first article above, I was enlightened that an SSR could be used to control the
heater in my SR800. I have a box with 7 SSR in it (hefty Opto-22 devices). So the big question
now is software and PWM.
Much to my surprise, the PWM default in the Arduino "AnalogWrite()" is 490 Hz!!
This is much faster than I would have expected, but apparently the SSR doesn't mind.
Reading about SSR devices, I see that SSR controlling AC will always turn on at
a zero crossing. As I read more, I get increasingly suspicious about aliasing
and a need for careful thinking about a rapid PWM rate like this.
Doing a search on "github arduino coffee roaster" will turn up all kinds of things.
These generally interface with Artisan via a serial link to whatever computer is
running Artisan.
Have any comments? Questions?
Drop me a line!
Tom's coffee pages / tom@mmto.org