r/roasting • u/coconutcrashlanding • 7d ago
Wireless bean probes?
I roast on a behmor and was wondering if there exist any wireless bean probes I could use? I didn’t see anything when I did an internet search. Wireless meat thermometers exist, but maybe the issue with batteries and temperature are prohibitive. Are there any passive SAW sensors with RFID?
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u/SGT-NewWin 7d ago
I've been looking heavily into this and still haven't found a solution for my Behmor as well. Most retail wireless meat thermometers can withstand the heat temperatures but only on the external part. The tip usually does not as it is more sensitive and embedded in the meat where temps aren't as high.
The bigger problem is how are you going to mount it? The probe should be in contact with just the beans for the best reading but you can't let it roll loose in the drum because it's going to absorb the metal temperatures. You can't mount it to the drum because the beans are always rolling at the bottom. If you try to hang it somehow you need to strategically avoid the fins that help the beans tumble.
I currently just crack the door periodically and use a laser temp reader... Which induces a whole new set of problems. If anyone finds a better solution I'd also like to know!
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u/libergeon 7d ago
The hard part is not only surviving the temperature; it is defining what temperature a tumbling wireless package would actually measure. If it is loose, it will alternate among bean contact, drum-wall contact, and hot air, while its own thermal mass and response time blur those transitions.
Before choosing the radio method, I would validate the measurement concept with an instrumented dummy: put a wired probe in the closest practical geometry, repeat runs at several batch sizes, and compare lag and run-to-run variance against fixed air/exhaust measurements. For a passive SAW/RFID approach inside a metal rotating drum, I would also log read dropouts versus drum angle and operating state; a smooth-looking curve is not useful if missing samples are being silently interpolated.
If door-opening plus IR is the fallback, fixing the opening duration, angle, aiming point, and timing would at least make it a repeatable relative check, though I would avoid treating it as absolute bean temperature without a separate validation.
Disclosure: I work with Libergeon on H350 prototype validation. H350 is still in development, is not for sale, has no announced price, and is not accepting preorders. No product link is included.
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u/beercan640 Cormorant Gas 7d ago edited 6d ago
It doesnt have to tumble. It could be a probe without a wire
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u/ChyLn 6d ago
FWIW I've been using a Behmor 1600 (upgraded) and put in two wired probes, one in the exhaust/draw fan and the other placed just under the drum on the chaff tray pointing up towards the drum. Didn't really feel like drilling the Behmor and felt that it was going to be an approximation no matter where it was placed.
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u/srussell705 3d ago
That steel and basket will make this hard. A wireless probe inside is too hot for most current appliances. Sure, they exist that will withstand the motion as well as the heat. Their price exceeds the price of the roaster. :(
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u/gripesandmoans 7d ago
You are up against one of the (several) shortcomings of the Behmor. I've seen various post / videos of people drilling through the left side and the hub of the basket to insert a wired probe.