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  • Gene Cafe & USB Datalogger

    Hi All,

    I have just taken delivery of my USB datalogger and plan to use it on my Gene Cafe. I was not sure where to mount the Thermocouple then I wondered whether the datalogger will take a signal direct from the Thermal Damper (out) that is in the Gene Cafe? Has anyone tried this? I am a little light on as far as the techical aspects of this (i can solder and am not worried about the power aspect). I am more interested in whether anyone knows what type of temperature reading the Gene Cafe is taking internally and whether that can be recorded via the datalogger.

    I have read all the posts where a guy installed the PID in the Gene Cafe and I see he installed another Thermocouple which seems a bit strange if there are already 2 temperature readings going on inside the Gene Cafe.

    Any knowledge and assistance would be apprieciated.

    Tks in advance as always.

    Simon

  • #2
    Re: Gene Cafe & USB Datalogger

    He probably installed the extra thermocouple as a dedicated input for the PID, so as to have a "clean" input and not unballance existing hardware

    Another way would be monitoring what the 2 existing sensors are doing using an Arduino piggybacked onto the existing lines. If you wanted to do PID, the same arduino could be used for controlling a SSR, logging, pre programming etc.

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    • #3
      Re: Gene Cafe & USB Datalogger

      Tks Subcontractor, the Aduino is a good suggestion. It require some testing however and I guess I run the risk that even this inteferes with the existing setup. In the meantime I have installed a Thermocouple in parrallel to the Thermal Damper (Out) in the exhaust port. I can see the simplicity of the approach outweighs the reverse engineering required to get a more integrated solution up at running.

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      • #4
        Re: Gene Cafe & USB Datalogger

        Id be interested to hear how the readings compare - The gene reports a temp that Im sure is nothing like bean mass temp, but Im used to how hard its pushing based on the target temp and reported temp. FWIW, I generally run it on about 232 until FC then drop back to 228 until I dump into the cooling bucket.

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        • #5
          Re: Gene Cafe & USB Datalogger

          Well I got some interesting data today. I did 4 roasts of 250grams each (2xColumbian Supremo,1&2, and 2xPeru Ceja De Selva estate,3&4). I have the short 25mm Thermocouple installed (the one in bean bay). It extends from the top of the exhaust port amost exactly in parrallel to the Genes Thermal Damper (out). At room temperature the Gene reads 27 C while my Thermocouple and another seperate probe Thermomenter read closer to 23 C also (so Thermocouple is 4 degrees lower than the Gene readout). Then when the roast process started the Gene seemed to lag behind the Thermocouple reading by quite a bit. I like to run the Gene a 150 C for 5mins for drying. In the period when the Gene hit 150, Roast 1 and Roast 4 (note different beans) ranged 153 to 158, while Roast 2 & 3 ranged 149 to 154; all higher than the Gene target of 150. The common thread is that roast 1 and 4 were from a cold(er) start than 2 & 3. When I cranked it up to 235 for the roasting after 5 mins and the Gene stabilised at 235 roast 1 read 240-244, roast 2 238 to 242, roast 3 238 to 242 and roast 4 239-243. In each case the Thermocouple was reading way higher than the Gene. I am not sure what to conclude other than the Gene temperature measurement is not very accurate, or lagging in some way. Regardless the ability to log the data by bean type means that the process is repeatable since the Gene inaccuracy is consistent at least . I can now see why PIDing the Gene would refine the process even more to make it more repeatable. A seperate Thermocouple has to be the way to go since the native Gene Thermal Damper doesnt look to be doing the job. This of course says nothing about the Bean Mass temp which is really what we want to measure, but cant in the Gene Cafe. I still love my little Gene though, but my quest for scientific and repeatable roasting is taking over I suspect. I can send the Roast Profile .csvs if anyone is interested.

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          • #6
            Re: Gene Cafe & USB Datalogger

            Hello Barra, a few months ago I installed a TC (the longer one that comes with the CS DMM kit) in my Gene. I drilled holes from the side, which is trickier than coming in from the front but I had to do it that way as I use the larger chaff collector. The TC then ends up positioned very close to the GC sensor.

            The TC and the GC sensor behave differently as they are heating up because they are different devices -- the one in the GC is a negative coefficient thermistor with a room temp resistance of about 1Megohm. However they track each other pretty well at roasting temps -- a delta of about 20C higher on the TC IIRC. To confirm this I superimposed on the TC log an OCR log from a video of the GC readout but cant find where I put it.

            As you say, the TC readings are quite repeatable.

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            • #7
              Re: Gene Cafe & USB Datalogger

              Im thinking of purchasing the USB Data Logger for my GC. Which thermocouple probe is better suited, 100mm or 25mm?

              Cheers

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              • #8
                Re: Gene Cafe & USB Datalogger

                I have both The 100m and the 25 mm thermocouples. I drilled in from the top of the exhaust vent. The 100mm is to long since it stops the chaff collecting going in easily. So the 25mm is the one to use.

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                • #9
                  Hi guys
                  Are there any pictures or instructions available on installing the probe
                  in th Cafe Gene?
                  I just got my roaster with the big chaff collector and wanna give the data logger a go.
                  Any help would be greatly appreciated
                  cheers

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