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Thermistor connections

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  • tfoutfou
    replied
    i have 13 onewire in star configuration and it work good


    only thing you need is 3 wire at each probe , maybe you have only 2 ?


    then at the central point you put your 12 positive wire together
    your 12 ground wire together
    your 12 data wire together

    then you connect it like it is only ONE probe and it must work (need only one 4.7K resistor between data line and positive)

    connect ground to ground on arduino , connect positive to 5v on arduino or from external 5v power supply (dont forget to connect commun ground if using power supply) , connect data line to the pin set in the plugin

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  • Jgarbus
    replied
    Typical voltage divider network with a fixed 10k at the arduino and the thermistor in the room being monitored. The 1-wire solution just does not work well unless I rewire the 12 rooms. everything is home run in a star configuration.

    The raw values coming back from the circuit are accurate and can be manipulated from 0 to 1023 using a decade box.

    I played with a few values in the sum field and ended up with Value/6.75 and the thermistor seems to track properly in an ice bath as well as up to and above room temp when compared to a 1-wire probe.

    Either I am over thinking the solution and the math is accurate or I just got really lucky

    If you have any ideas on how to get the 1-wire to work in a star, let me know. I have 2 dozen 1-wire sensors in hand ready to go.

    FYI 1 wire sensor is US $1.50 and a 10k thermistor is $0.50

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  • tfoutfou
    replied
    we would need you schematic and thermistor value at different temp to start with


    However i would advise to use DS18B20 temperature sensors because they are precise and cheap , and not affected by length of wiring

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  • Jgarbus
    started a topic Thermistor connections

    Thermistor connections

    Has anyone had success using 10K thermistors with this plug in. I have been messing with it all day and cant seem to figure out how to turn the returned value into something usable.
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