Dallas D18b20, powering

I've got this working with parasite power but i wanted to experiment powering it externally. can i use the 5v pin on the arduino to supply the Vdd pin on the sensor? do i still need the pull-up resistor?

how would i hook it up, i've tried the above and it hasn't worked so far

Greenbeast,

I just did some experimenting on my setup using DS18B20 temperature sensors. I decided to power the sensors so I could get quick response times.

I have wired my DS18B20's with 5V, Gnd, and a pull up resistor from 5V to the signal wire. Since I am going to be daisy chaining a number of these together, I soldered a female header on a shield so I can readily change the pull up resistor.

I just tried some experiments with the pull up resistor values. For 2 sensors, I tried "open", or no resistor and then a 100K resistor. Neither of those worked. With a 20K, 4.7K, 2.2K and a 1K, each of those worked. The 4.7K is the recommended starting point.

See Miles Burton's library at: http://milesburton.com/wiki/index.php?title=Dallas_Temperature_Control_Library. I found this on the Playground links.

Also, I am having my own issues with the Temp Sensors once I open up a file on a Secure Digital card. :( Please see http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1270923978/0#3. If you have any suggestions, I would really appreciate a reply.

Good luck!

can i use the 5v pin on the arduino to supply the Vdd pin on the sensor?

Yes

do i still need the pull-up resistor?

Yes.

So I don't know why you didn't get it to work.

With a 20K, 4.7K, 2.2K and a 1K, each of those worked. The 4.7K is the recommended starting point.

I was just about to break down and ask about that, I've got a bunch of 2k's and zero 4.7k resistors :)

i happened to be using two 10k resistors in parallel which works fine for parasitically powered.

I've got an lcd hooked up to some of the same wires (power and ground) so perhaps i've got the wiring wrong somewhere. Now i know what i was trying is possible i'll take the screen off and try again

Thanks

Hi, i'm having the same problem. there is no way to connect the sensor to arduino without resistor? I don't have the 4.7k and don't sell near from here ! =/