[Homeroast] I-Roast2 malfunctions

Allon Stern allon at radioactive.org
Tue Dec 29 20:37:24 CST 2009

On Dec 28, 2009, at 8:14 PM, Dave McCracken wrote:

> The reason I'm convinced it was the thermal sensor is when I'd push the button 
> to get a temperature reading, I'd see it occasionally jump from its true 
> temperature to some random value 50 degrees or more higher, then immediately 
> drop back.  My assumption is that at some point the false high reading would 
> be high enough to trigger the overheat shutdown.  And since it was so 
> transient it would immediately be ready to start another roast.  You might try 
> checking the temperature readings on yours to see if you get the same 
> transient high temperature anomalies.

Well, I doubt that - the thermal cutout is a separate component from the logic, a commodity part that does only one thing - it senses when the temperature is above a set point, and opens a circuit. 

The temperature sensing by the iRoast is a separate control loop (and I use the word "control" here very loosely - the iRoast, despite its apparent programability, really gives you very little flexibility. Too bad its temperature sensor SUCKS. It would probably work just as well with the sensor removed.

That said, once you learn how to game the system with the iRoast, you can get quite acceptable roasts out of it.

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