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Behmor Mod #4 & 5 Computer controlled and buzzer

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  • Behmor Mod #4 & 5 Computer controlled and buzzer

    Woo Hoo!!!

    I can now temperature control the Behmor using Artisan. I initially built an Arduino based HID as a stand alone device to digitally control the temp. This allowed me to infinitely vary the heater output. Yesterday I figured out how to get Artisan to talk to my device, Big Win!!!

    Next step is my holy grail, to automate the roasting.

    While I had the Behmor apart I had a crack at installing a buzzer whenever the display flashes. It was much more difficult than I thought. My current solution involves some additional circuitry installed in the Behmor and in my HID. It essentially measures the voltage going to the display (much more difficult than it sounds) and triggers a buzzer when it crosses a predetermine threshold. The threshold still needs some tweaking as it is sounding at random times during the roast. Unfortunately the threshold is hard coded (lack of foresight) which makes testing a slow process. I may have to make it user adjustable if I can't figure it out soon. In the mean time, I am still using a timer as a backup.

    If anyone has an easy way to implementing a buzzer I'd love to know. FYI the Behmor uses a 44 pin SH69P55AF microprocessor and there are spare pins if anyone knows how to reprogram it.

    Atm I'm still waiting on some parts. Once the build is complete it will all go into a nice pretty enclosure and look not so DIY.
    Attached Files

  • #2
    Functional diagram
    Click image for larger version

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    • #3
      Clever boy


      • #4
        A fun project.

        my holy grail, to automate the roasting.
        as someone who had a computer controlled Behmor 5 or 6 years ago and has a commercial roaster that can also be controlled by a computer I can tell you it isn't the holy grail... even though you think it is now.

        Semi controlled produces a far better result... or just use the computer to protect your roast if you are distracted. I believe that no amount of programming replaces raw ability of the user.

        uses a 44 pin SH69P55AF microprocessor and there are spare pins if anyone knows how to reprogram it.
        A good thought but that won't happen as you can't "reprogram" that chipset. All you can do is run the 44 pins off-board to another chipset and program that. (spoken from experience, not guess work)

        Enjoy the project just the same.


        • #5
          Yeah it was fun actually. No doubt you are right about my interpretation of my Holy Grail. I'll re-adjust my exceptions to semi-controlled with a watchful eye

          Good to know early on reprogramming the chip isn't possible. Saves me potentially hours/days trying to figure it out. Hadn't thought of running another one in parallel. That would be pretty cool but probably not worth the effort just for a buzzer. Mine works well enough but it's quite complex so more things to go wrong. There must be a simpler solution.


          • #6
            That is awesome, well done! Nothing like a successful tinkering project. Would love to get a buzzer for the reset requirement.

            Are you monitoring the B temp? I have found at full power you can trigger the B over temp, at 165 degrees from memory.

            Are you using bean temp probe as your reference?



            • #7
              Not sure what B temp is but if it is something that Behmor measures then no, I don't monitor it.

              I do monitor bean temp, chamber temp, heater element temp and exhaust temp with the C304. After a year I'm yet to hit any over temp threshold.

              Yeah the lack of buzzer is a PITA. I tried to keep it simple but couldn't. The end solution involved some reasonably complex wiring and coding which given its complexity makes me nervous. Anyway today I just twigged that Artisan has it's own set of alarms and even a beeper so I'll have a play with that. Who knows, the solution may have been there all along.


              • #8
                On the plus panel if you press A you get the exhaust temp and B is the wall temp (measured by one of the sensors on the bottom right). If it gets over 165 (or 166 can't recall) the roaster shuts down.

                I have got close with a large batch and especially if pre heating.



                • #9
                  oh. I preheat to 150C chamber temp as measured where the heatsnob was installed. Seems to be ok.