OneWire with Duemilanove

Forum 2005-2010 (read only) Hardware Interfacing
1

I am trying to connect DS18S20 to Arduino Duemilanove, using software version 0012.
I am using DS18S20s on parasite power. There is 4k7 pullup resistor on system.
Using OneWire library found from Arduino site with sample code I am getting output as below.
So, room temp. is approx 26C (It's summer here), but sensors shows temp eg. 3.68C.
I know I am doing something wrong, but I don't know what it is.

R=10 54 DC 9D 0 8 0 7C P=1 3A 0 57 52 FF FF 9 10 FB  CRC=FB
3.62
R=10 BC AD 9D 0 8 0 54 P=1 3C 0 4B 46 FF FF D 10 16  CRC=16
3.75
R=10 26 D7 9D 0 8 0 FA P=1 3B 0 77 72 FF FF 4 10 7F  CRC=7F
3.68
No more addresses.

Thanks for you help.

2

You have the DS18S20 sensor which returns the temperature in a 9-bit format. However the code you are using to convert the temperature is for the DS18B20 sensor, which is 12-bits.

See this thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1229294555
The last post has the conversion code which will work for you.

3

Thank you Waffle, that made it working.