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DS18B20 is not being recognised by Raspberry Pi 2

Paul Baranowski
Prodigy 20 points
Other Parts Discussed in Thread: LMT01, TMP107

I have wired up my Raspberry Pi (RPI-0007) to the pins as outlined by http://www.modmypi.com/blog/ds18b20-one-wire-digital-temperature-sensor-and-the-raspberry-pi. However, when I change directory to /sys/bus/w1/devices nothing is there. 

I have added dtoverlay=w1-gpio,gpiopin=4 to the boot config file (sudo nano /boot/config.txt) and rebooted but nothing is working. I have checked the wires, loaded the modules and checked the sensor is receiving power (using an LED on the breadboard).

You can see a thorough description of my problem with pictures as well on Stack Exchange: raspberrypi.stackexchange.com/.../raspberry-pi-b-wont-recognise-ds18b20-sensor

  • 0
    TI__Expert 7945 points

    Hello Paul,

    Thanks for reaching out to us on your DS18B20 questions. I'm unable to debug your issue from my end. Also please note that DS18B20 is not a TI temperature sensor. On the other hand, we do have a temperature sensors like TMP107 and LMT01 that will very likely fit the needs of our customers who may experience certain shortcomings from DS18B20. We will always be glad to assist you for any further needs.

    Take care,
    Abhi

  • 0 in reply to Abhishek Muppiri
    Prodigy 20 points
    Hi Abhi,

    Apologies, I have no idea why I thought it was one of your sensors - I have been looking at your site for a number of sensors and must have confused myself. Could you explain the difference between the TMP107 and LMT01 in a practical sense, is it purely the accuracy? I would be using it with a Raspberry Pi and possibly later an Arduino.

    Best wishes,
    Paul
  • 0 in reply to Paul Baranowski
    TI__Intellectual 910 points
    Paul,
    Great question! The LMT01 and TMP107 are designed be place on the PCB or at the end of a cable.

    The LMT01 is designed with a super simple pulse counter interface where each pulse represents 1 LSB. The device only has 2 pins, where power and communications is shared as the pulses are generated by modulating the current.

    The TMP107 is a daisy topology temperature sensor where each device repeats to the next node allowing up to 32 sensors per chain. It communicates with the MCU via a 1/2 duplex UART interface. SW is greatly simplified over the DS18B20 with automatic addressing and global read/write commands. The TMP107 also includes non-volatile memory and ±0.4°C (max) from –20°C to +70°C.

    Both parts are also significantly lower power than the DS18B20.

    I could go on.. But I'll let the parts speak for themselves. :)
    Daniel
  • 0 in reply to DMAR
    Intellectual 640 points
    Hi,

    I am wondering if you can advise me where or how can I make a water proof temperature probe (with cable and metallic case) like this www.tweaking4all.com/.../ds18b20-waterproof.jpg but using the LMT01 instead.
    Thanks!

    Miguel
  • 0 in reply to Miguel Bento
    TI__Expert 7220 points
    Hi Miguel,

    See this E2E post: e2e.ti.com/.../465898

    -Michael Wong
  • 0 in reply to Michael Wong
    Intellectual 640 points
    Hi Michael,

    That sounds nice. My question is how can I produce this kind of probes massively? Like 5k or 10k.
    Thank you.