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Has anyone tried any of the cheap DS1820 Dallas Temp sensors from China on e-Bay? — Parallax Forums

Has anyone tried any of the cheap DS1820 Dallas Temp sensors from China on e-Bay?

zoopydogsitzoopydogsit Posts: 174
edited 2012-01-12 14:34 in General Discussion
Folks,
I was thinking of doing some temperature sensing around the house, and was considering the Dallas DS1820, though they are usually quite expensive. However I've found some unbelievably (too good to be true?) cheap prices for 10 units including shipping. Obviously I'd prefer to deploy more sensors at a cheaper price than few at a more expensive price.....

Has anyone tried these and actually found them to work? Or is this just another rebadge of an existing semiconductor to make a few quick bucks?

$12.88 & free shipping for 10 units, where I'd pay $8.88 each + shipping at Element14, and similar prices from the other guys.
http://www.ebay.com.au/itm/10pcs-DS18B20-DS1820-1-Wire-Digital-Thermometer-Dallas-/180692488653?pt=LH_DefaultDomain_0&hash=item2a121c91cd

I may have to do the experiment, buy one locally, get it to work, then buy the cheapies from China and confirm they are the real thing.

Also, if you've used the DS1820s which variant have you had the most success/prefer.

Comments

  • ElectricAyeElectricAye Posts: 4,561
    edited 2012-01-07 23:02
    zoopydogsit wrote: »
    ... I'd pay $8.88 each + shipping at Element14....

    I'm not sure where you're located but Digikey has them at about $5 each, Priority Mail would get them to you in about 2 days if you're in the USA. http://search.digikey.com/us/en/products/DS18B20%2B/DS18B20%2B-ND/956983

    Of course it's hard to beat those Chinese prices. Hard to tell if they're counterfeits, too. Until they fry out.

    If you work with these sensors, you might have a look at the following thread:
    http://forums.parallax.com/showthread.php?136782-There-is-something-wrong-with-Micah-Dowty-s-1-Wire-object-in-the-Obex.&p=1060896&viewfull=1#post1060896
  • TubularTubular Posts: 4,717
    edited 2012-01-08 03:16
    Altronics wholesale $2.44ea for 10+, $2.22 for 50+,
    But for around the house you will probably be fine off ebay
  • doggiedocdoggiedoc Posts: 2,245
    edited 2012-01-08 06:04
    Heck, for $12.88US - I'd say just order some. Like tubular said, for around the house tinkering - no worries. If you are building a project for a client though, I'd think twice.

    Paul
  • ercoerco Posts: 20,259
    edited 2012-01-08 08:57
    Yes, I've tried an Ebay China $12 10-pack of DS18B20, and they worked as advertised with a PicAxe. I just gave two of them them a quick go/no go test which they passed, but I can't comment on their accuracy or reliability.
  • kwinnkwinn Posts: 8,697
    edited 2012-01-08 09:39
    Not much one can do about reliability but you can add correction factors to the software for calibration as long as the readings are repeatable.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2012-01-08 10:27
    kwinn wrote: »
    Not much one can do about reliability but you can add correction factors to the software for calibration as long as the readings are repeatable.

    kwinn has a good point. If they were dumped because their lot was out of spec, then you might be able to tweak their outputs. My recent pack of DS18B20 sensors indicate they were made in Malaysia, so the Hong Kong dudes might be trafficking in genuine industrial surplus, out of spec lots, or "third shift" production runs. Who knows?
  • ercoerco Posts: 20,259
    edited 2012-01-12 14:34
    http://www.phanderson.com/picaxe sells them for $3.75 each, or in a weatherproof (waterproof?) cable for $6.95. ~2/3 down the page.
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