Tuesday, October 20, 2009

Wire length

I got comment from Stephane about wanting to know, how long CAT5E ethernet cable can be used. Well, I just bought a 100 meters (328 feet) of wire. Not CAT5E ethernet cable, but 4 wire flat telephone cable. I connected one temperature sensor DS18S20 at one end and DS9490R USB adapter to another. Under /media/1wire/ folder I got new folder "10.BCD8ED010800" and I got even a reading from it.
$ cat /media/1wire/10.BCD8ED010800/temperature
$ cat /media/1wire/10.BCD8ED010800/power

power file shows that it's powered parasitically.

I don't know how many sensors I can connect to 100 meeter cable before I have to add additional power, but if I got reading from 100 meeter cable, then I am sure I get readings of many sensors with external power. Just found guidelines page. In my case, I probably need total of 50 meters of wiring.


  1. Hello,

    Thanks for the info ! I used the CAT5E ethernet cables I already had (around 30m) with 2 DS28S20 and it worked without problem.


  2. Stephane, do you plan to just monitor or also to control something?

  3. pets,
    Have you done any more withe the one-wire since your last blog entry>

  4. I discovered, that laptop or software I used is not very stable. It works some weeks and then something hapen's and 1-wire system goes down and I have to reboot to get everything working again. And I don't like that laptop because it's fan is making some noise and I want silent system. I have bought a WD TV Live. It runs on linux and I already tried to compile the same software for it but it fails. But there is hope that b-rad, who makes custom firmware for WD TV Live will compile it and include this software in future releases. Then I can test the stability again.