A month after Marko Luther suggested that I would look into serious PID'ing of my roaster and after much preparation and testing, the PXG4 is now complete, built in its box and functioning well:
Fuji PXG4 built in box prepared by Tije
Back view
The complete set of 3: roaster, controller, monitor
Halfway in roast sequence
In the graph below, the red line shows the target bean temp, the black line the actual temp and the yellow line shows how much labor the heaterhas done, controlled by the PXG4, between 0% -- 100% of maximum power, to keep the bean temp in the exact range.
Complete roast log graph
Roast ready
PS addition almost a year later I have moved on to different roast profiles, primarily after reading Scott Rao's book about roasting:
PS 4 January 2018:
Jean-Claude van Damme uses the same box from Conrad in his new action here series.
(also see Daily Coffee News feature ) Tije designed and made the following structure for a tiny and cheap fluid bed roaster, to which Jan van der Weel added the Arduino parts, electronics and programming: Sketch by Tije de Jong Jan sourced a very cheap blower (€ 11) to start with, Tije developed and constructed the mechanics, Jan built together and programmed the TC4 / SSR electronics. On his blog, Jan will specify exactly how the TC4 part is combined and programmed and I will copy these details into this blog entry, just as Jan will use this video in his blog. We did a few test roasts to make sure it works at all and it does. Towards the end, the first roast tended to get a flat BT line and airflow was slightly decreased. 200g seems max load of green beans. Second roast a little more power was given to the heater. Next we will try the Background Roast driven by the PID software of Artisan. A week later, with updated software that works better to change the fan
(Finished project on http://kostverlorenvaart.blogspot.nl/2015/01/finished-pavoni-fuji-pxg4-pid-probe.html ) Several models of espresso machines have a PID on board these days. As far as I know, all of these are used as mere thermostats, making sure the boiler (and sometimes a second boiler) is kept at the right designated temperature, and since temperature and pressure go hand in hand inside a boiler, also the correct pressure. For a brew boiler, the temperature is most important even though the pre-infusion pressure is relevant as well in a lever machine. For a steam boiler, the pressure is most important to be able to steam that milk to a creamy froth. Still, these values, pressure and temperature , cannot be seen separately. A problem for most PID devices is that it's HOT inside an espresso machine, around 50ºC and the PIDs are mostly designed to survive in an environment of 60ºC maximum. The result is that such a PID inside often has a limited lifetime. On the curr
illustration by Matthias Gerstgrasser On the mailing list for Artisan users , Matthias Gerstgrasser posted a report about his coffee roaster project, with a link to a beautifully illustrated, complete step by step guide of his work on Instructables: A while ago I posted a few messages on here regarding automation for my hot-air popcorn roaster, and was asked if I could share a writeup of what I had been doing with my setup. I know it’s been a long time, but I haven’t forgotten, just got a little sidetracked (more on that below). I have finally found time to do this over the last few weeks though, and compiled a step-by-step guide of how I modified my popcorn machine. This is now available on Instructables: https://www.instructables.com/id/Arduino-controlled-DIY-Coffee-Roaster/ Do let me know if there’s anything missing or anything that could be improved. I intend to keep updating the guide as I find ways to improve it or as new developments occur. I am also discussing b
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