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1 wire bus

Former Member

Hi Peeps,

 

I am about to embark on a 1 wire bus project using devices such as the Maxim DS18S20DS18S20+ temperature sensor and other similar devices. The idea of the 1 wire bus seems groovy enough but I wondered if anyone out there had any experience of this stuff.

 

The concept of the project is in 2 major parts, the physical hardware implementation of devices connected ono the 1 wire bus along with a USB transciever to connect it into the main motherboard. The second part is the software which will be Linux based and the idea is to use the Linux DBUS mechanism to create a self describing (a method called introspection) platform for applications which are interested to get hold of sensor data. There is actually a 3rd parrt to this project which is the applications themselves, but before I go blabbing on in detail about the project I thought I ought to see if anyone has any comments to make first.

 

Fire away

Parents

  • Hello,

     

    I have a 1-wire network using 2 DS18B20's and an Embedded Data Systems HA7E 1-wire adapter in parasitic configuration. As the HA7E uses ASCII commands I use an Applescript to get the data from the sensors. The script basically polls one sensor then the other and writes the temps to a variable in my automation software.

     

    I've been having trouble with intermittent erroneous readings of 4095 a few times a day. I read that you need a 4.7k pull up resistor. I couldn't find a clear explanation of how to install it but from what I read it goes between 2 and pin 1/3 (they are soldered together for parasitic mode. I did the first sensor in the my network leg  and when I tried I got a constant 4095 reading from both sensors.

     

    Am I doing something wrong? I read on another site you need a diode to correct erroneous readings. I am a bit confused so if you can give me some advise I'd be most appreciative.

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  • Hello,

     

    I have a 1-wire network using 2 DS18B20's and an Embedded Data Systems HA7E 1-wire adapter in parasitic configuration. As the HA7E uses ASCII commands I use an Applescript to get the data from the sensors. The script basically polls one sensor then the other and writes the temps to a variable in my automation software.

     

    I've been having trouble with intermittent erroneous readings of 4095 a few times a day. I read that you need a 4.7k pull up resistor. I couldn't find a clear explanation of how to install it but from what I read it goes between 2 and pin 1/3 (they are soldered together for parasitic mode. I did the first sensor in the my network leg  and when I tried I got a constant 4095 reading from both sensors.

     

    Am I doing something wrong? I read on another site you need a diode to correct erroneous readings. I am a bit confused so if you can give me some advise I'd be most appreciative.

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