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What is the normal connector that people put at the end of a long cable with a MAX31820 / DS18B20 temperature sensor at the other end? What is the normal connector that people solder to the PCB when they intend such a cable to be plugged into that PCB?

I'm making a PCB that will go inside a small refrigerated box that (among other things) measures the temperature at various "interesting" locations inside that box and the ambient temperature outside the box, and drives a Peltier thermoelectric cooler (TEC) to keep that box at the desired setpoint temperature.

The MAX31820 / DS18B20 temperature sensor at each location are all wired in parallel in a 1-wire bus. There will be multiple sensors. (It's actually 3 wires :-).

My Google searches turn up several pages that seem to say "there is now a standard for connector pin-outs" for the 1-wire bus, but each site's explanation of "the" standard seems to contradict the other sites.

Several different "standard" connectors and pinouts are listed in:
http://www.midondesign.com/Documents/1-WireApplicationGuide103.pdf
http://www.hw-group.com/products/poseidon/pos_interfaces_en.html
http://arduino-info.wikispaces.com/Brick-Temperature-DS18B20
-- each one shows at least 2 different connectors or pinouts on a connector. Is one of these (or perhaps something else) the current de-facto standard?

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  • \$\begingroup\$ There's a standard for these things? I thought they were just TO-92 or DIL8/SOIC8 devices. \$\endgroup\$ – Ignacio Vazquez-Abrams Sep 27 '14 at 0:55
  • \$\begingroup\$ @IgnacioVazquez-Abrams: As the links in the original question show, not only is there a standard for these things, there are several standards -- hence the question. \$\endgroup\$ – davidcary Sep 27 '14 at 1:03
  • \$\begingroup\$ Have you looked at the "1Wire.org draft standard for RJ45" yet? \$\endgroup\$ – Ignacio Vazquez-Abrams Sep 27 '14 at 1:21
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    \$\begingroup\$ As a one off, why bother? \$\endgroup\$ – Passerby Sep 27 '14 at 1:58
  • \$\begingroup\$ @davidcary Are you planning to interface with existing 1-wire hosts or peripherals? \$\endgroup\$ – Nick Alexeev Sep 27 '14 at 2:09
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[This started as a comment, but I've run out of room. Systems engineering is wordy work.]

I've tried to look up the draft standard mentioned in the comments, but to almost no avail. The website 1Wire.org seems to be defunct. The best pinout information is on pp.13-14 of the 1-Wire Application Guide 1.03, which David (the O.P.) have dug up.

David, I understand your question, but I don't understand your problem. Please correct me if I'm wrong with the following.

  1. Are you planning to use an existing 1-wire host box?
    Looks like you don't. If you did, you would be forced to conform to the pinout of that hypothetical box.
  2. Are you planning to use an existing sensor with a connector?
    Again, it looks like you don't. If you did, the sensor would force the pinout on you. So far, you have been mentioning sensors packaged in TO-92.
  3. Are you planning to sell your the sensor assemblies to the 3rd parties, so that they can use it with host boxes that are already out there?

The RJ-11 cable is the thinnest, cheapest (between Between RJ-11, RJ-12 and RJ-45). For a relatively closed system whose components don't interface with 3rd party components, I would pick a common RJ-11 pinout from the table on p.13 and use that.

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I meant as a one-off project, worrying about "de-facto standards" is pointless.

If this is

  • a single fridge
  • with short runs and
  • you don't expect it to be modular or connecting and unconnecting
  • nor multiple people working on it

any connection would work:

  • wire straight to pcb

  • RJ-11 (telephone connector)

  • 3.5mm TRS audio connectors (don't plug in/out when powered)

  • screw terminals

  • 1" headers

  • or any combination of them.

If you simply must have a connector, a fairly simple method would be a 5-way telephone splitter, with the connection to your board being soldered wire, but the sensor wire runs terminating in the RJ-11 jacks.

enter image description here

In fact, someone did exactly that for their Arduino 1-Wire project (with telephone wall jack boxes holding the sensors as well): enter image description here

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