Temperature Logger using DS1820 and PIC 16L84 Microcontroller

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There has been quite a few temperature devices featured here in the past. This temperature logger is nice since it uses one of my favorite temperature sensing chips, the DS18B20. This sensor is digital and does not need any calibration. When I make my next batch of home brew beer there will definitely be a DS18B20 floating in it. Or if I have some extra DS1822 devices from the fish tank light project I might just use those…

“The logger probes measure temperatures from –55°C to +125°C (–67°F to +257°F). No calibration required.

A PIC Arbiter acts as interface between the Dallas temperature sensors and a logging PC. There are 8 terminations or single wire busses. Each of the 8 busses can support up to 8 sensors. As many sensors can be installed as required, limited to 64 maximum.

I have called it an Arbiter as the controller negotiates with each probe on the single wire bus. Each individual Dallas temperature sensor unique serial number. Where a particular probe is in relation to its peers, or particular bus pin on the PIC is irrelevant. The Arbiter sends to the PC the unique serial number of the temperature probe and its temperature in a serial frame.

The PIC Arbiter identifies sensors on each bus. Additional sensors can be plugged in at any time. Each device is polled every five seconds: its address and temperature data are sent via a RS232 serial link to the PC.”

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12 Comments



  2. I wonder if this could be used in conjunction with the networked weather module on the 7th


  3. help me sir,
    plz guide me.
    this site is cracking.


  4. Hi Karan,

    There is more information on the authors site, simply click on the link in the article.


  5. Hi All,

    I just wonder whether hotbox software works with Windows XP Home Edition Version 2002 SP2 without any DLL library.
    I cannot make it work. I can get serial frames through Hyperterminal as mentioned in the article, but when I run hotbox.exe I get “fail to open comunications port xx”.

    Thanks in advance for help
    Ales


  6. It is working now!

    I swapped ports. with port 23 it was not working, but when I change it to port name with single number …100% success.

    Cheers,
    Ales


  7. Glad to hear you got it going. What are you monitoring with it?


  8. Well, I would like to use it for family house. (monitoring furnace, teperature in rooms on the ground,1st and 2nd floor, outside temperature, beehouse) Also I would like to create several simple LCD terminals so I can take the reading at least on each floor without PC.


  9. Hallo, I found your project but the link to anotherurl is dead and so i hope there is another source for your project ?


  10. @Alan Parekh –

    links are all active as of 1 NOV 08.

    GREAT project, and just what I was looking for. I am starting with a home refrigeration monitoring setup, then expanding to whole house systems.

    Next step is research into other 1-wire sensors in the lineup. Water detection is a big one…

    Thanks again Alan!!!


  11. Dear Sir,
    Following is the description of our requirement.
    We have a Controlled Atmosphere Cold Storage facility.
    The room size is 6.5 meters x 13 meters and height is 6.5 meters. There are 8 rooms.
    6 sensors to be placed in different locations in each room. Power available in each room. We can bring sensor wires to control room. Maximum distance will be 85 meters. Accuracy of measurement required is 0.15 deg. C. Temperature range is -1 to 15 deg. C. Logging required every hour and on demand on PC with windows XP and Excel. Total 48 sensors.
    Please suggest cheapest solution.
    With Best Regards,
    Dawood

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