Probably the DS18B20. It has three cables: positive, negative and data. It can run in parasitic mode if the positive is wired to the negative and the data is given positive voltage. Very accurate sensors but some are not built as well as others if being used in an outdoor environment.
On Thu, Aug 1, 2019 at 11:01 AM <[email protected]> wrote: > About 20 years ago I made a device that would measure temps in an HVAC > system. One of the spots was on the evaporator, I don’t remember the other > place. I developed it in conjunction with an HVAC dealer. It could detect > when things started to go bad and call in and send an alarm. Used mostly > in Florida. They called indoor comfort security and they sold it on a a > recurring revenue/alarm basis. > > It had these Dallas Semiconductor transistor looking thingys for temp > probes. They were one wire and ground. Full digital. Wire length was not > an issue. It was fun designing that one wire half duplex driver in the > MCU. I put them on the end of long silver satin telephone line cords. > Soldered on one end with heat shrink. The other end were RJ11 or RJ12. > > In any event, nice temp sensor. No analog involved. DS1820 I think. > Very easy to add temps to an digital system. > > *From:* Forrest Christian (List Account) > *Sent:* Wednesday, July 31, 2019 11:39 PM > *To:* AnimalFarm Microwave Users Group > *Subject:* Re: [AFMUG] Extending Packetflux Temp Probe > > Yes, it's high enough resistance that the added cable length won't be a > problem. > > On Wed, Jul 31, 2019, 11:15 PM Jason McKemie < > [email protected]> wrote: > >> Is it okay to extend the wire for a sitemonitor temperature probe by a >> couple of feet? I just want to make sure it is not going to throw anything >> off. -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> > ------------------------------ > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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