cheap ds18b20's, are they legit??

[ScaleRobotics]

That's good to hear. Maybe someone just bought too many, and now they are trying to get rid of them. Still makes me skeptical though, and free shipping. (I might have to buy some!) Do you have a camera that can take a photo of the front in macro? Not sure we would see anything, but it might be interesting to compare to known samples.

[Heckler]

YEP!! they are all reading very close to each other...
Below is a sequential read of nine sensors that are all in parallel on a bread board:

1 TempC = +25.1250 C
2 TempC = +25.2500 C
3 TempC = +25.1875 C
4 TempC = +25.1250 C
5 TempC = +25.625 C
6 TempC = +25.625 C
7 TempC = +25.625 C
8 TempC = +25.625 C
9 TempC = +25.0 C

I modified Bruces code that is posted on rentron. First I read each serial number and made a note of it as I placed it in line on the bread board. Then I did a For/Next read of each sensor and displayed the temp using debug.

I also sequentially touched each one with a hot soldering iron and watched just that sensor change in value confirming that I, indeed, was reading each sensor.





If anybody is interested in my test code... I would be happy to post it. I used a 16F690 on a Microchip LowPinCount demo board with pickit2. You can see all nine sensors lined up 3 x 3 on the breadboard.

[Heckler]

Also please note the above ebay listing is actually NOT the vendor I purchased from... I bought from this vendor...
http://cgi.ebay.com/10-QTY-DS18B20-T...item1c1b21e8c3

I paid $15USD
Now he is selling them for even CHEAPER!!! 10 for $9.80
The vendor ID is cwithk.


Here is the latest read of all nine sensors:
1 TempC = +25.3125 C
2 TempC = +25.4375 C
3 TempC = +25.3750 C
4 TempC = +25.3750 C
5 TempC = +25.2500 C
6 TempC = +25.2500 C
7 TempC = +25.1875 C
8 TempC = +25.2500 C
9 TempC = +25.1875 C

[Archangel]

If anybody is interested in my test code... I would be happy to post it. I used a 16F690 on a Microchip LowPinCount demo board with pickit2. You can see all nine sensors lined up 3 x 3 on the breadboard.

I would say Please post your code, someone will find it useful, I will archive it as an example in MY Computer, for sometime in the future, I am sure I will not be the only one. BTW I use those demo boards too . . .
If the chips actually work, I doubt they're counterfeits, it would not surprise me if they are old or not RoHS compliant.
Order 2500 at mouser for $2.09 each . . . I am getting even more sure of my opinion about old stock . . . and those You have shown, Look Old too . . . http://www.mouser.com/Search/Refine.aspx?Keyword=DS18B20&Ns=Pricing|0&FS=True

[mackrackit]

I say post your code as an article. Very interesting test project.