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    DS18B20 @ Grove Connector

    M5 Stick/StickC
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    • C
      ckuehnel
      last edited by

      I connected an DS18B20 w/ pullup to the Grove connector and want to readout temperature. No success.
      Connecting it to the header GND, VCC and G26 it works as expected.
      I tried G32 and G33 at Grove w/o success.
      What's wrong there?

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      • grelmG
        grelm
        last edited by grelm

        I would like to do temperature measurements with 6 x DS18B20 connected to an M5Stack-FIRE.
        I am little confused by the work and description of ckuehnel and would like to ask the following questions.

        Do I understand it correct:

        • It works fine, if all 6 sensors are connected "in parallel" to the GROVE-PORT B (GND=black, 5V=red, G26=yellow) plus the 4,7kohm resistor?

        • There is NO need to access any I/O-pins via the M-bus-connector?

        0_1559840519810_GROVE-Connector FIRE s.jpg

        Programming M5Stack Fire with Arduino for Home Automation

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        • grelmG
          grelm
          last edited by

          Additional questions regarding connecting temperature sensor DS18B20 to M5Stack-FIRE:

          What is the maximum possible cable-length of a DS18B20 temperature sensor connected to a M5Stack-FIre if:

          • a) only one single Sensor is connected?
          • b) 6 sensors are connected?

          Programming M5Stack Fire with Arduino for Home Automation

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          • L
            liushasha
            last edited by

            @grelm Does DS18B20 have a unique address to identify the 6 sensors if they don't have an address, or they share the same address you can not expect reading correct data from them, they will have conflicts by wiring them all to one G26 pin.

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            • ajb2k3A
              ajb2k3
              last edited by

              If I recall correctly, they should have been given individual different numbers in the factory.
              Wire length is unknown but for unshielded cables I would recommend keeping them very short for data. If you are getting issues, you may need to look at making some shielded cables.
              Does Changing cable lengths result different readings?
              You may also need an additional power supply to the device.

              UIFlow, so easy an adult can learn it!
              If I don't know it, be patient!
              I've ether not learned it or am too drunk to remember it!
              Author of the WIP UIFlow Handbook!
              M5Black, Go, Stick, Core2, and so much more it cant be fit in here!

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              • grelmG
                grelm
                last edited by

                Adress-Issue: Extract from data sheet:
                Each DS18B20 has a unique 64-bit serial code, which
                allows multiple DS18B20s to function on the same 1-Wire
                bus. Thus, it is simple to use one microprocessor to
                control many DS18B20s distributed over a large area.

                So I think, I can really run 6 Sensors on ONE GOVE-Port (B)!

                Power Supply:
                According to data sheet, a single DS18B20 draws 1,5 mA max. during conversion.
                In addition to that there is the current thru the necessary 4,7 kOhm resistor = 1 mA.
                In total there will be abut 10 mA (incl. some reserve) needed from the 5V-pin of the GROVE.port.
                How high is the maximum recomended current which a GROVE-Port can deliver?

                Cable-length:
                I think, I will have to do some testing.
                As soon as I am done with it, I am going to post the results on that in this forum.

                Programming M5Stack Fire with Arduino for Home Automation

                ajb2k3A 1 Reply Last reply Reply Quote 1
                • ajb2k3A
                  ajb2k3 @grelm
                  last edited by

                  @grelm I think (but i could be wrong) 10mA should be ok.

                  UIFlow, so easy an adult can learn it!
                  If I don't know it, be patient!
                  I've ether not learned it or am too drunk to remember it!
                  Author of the WIP UIFlow Handbook!
                  M5Black, Go, Stick, Core2, and so much more it cant be fit in here!

                  1 Reply Last reply Reply Quote 0
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