1 wire Temp sensor [Archive] - MEL PICBASIC Forum

PortlandJohn

- 24th November 2005, 22:33

I am trying to use a DS1821 1-wire temperature sensor with a 16F877a. Using the OWIN and OWOUT commands I can see the signals going out on my scope but the sensor does not respond.
Has anyone got any good ideas or working code samples.

Thanks

John

CocaColaKid

- 25th November 2005, 14:13

I've played with the 18B20 and the 18S20 with great success. I'm not too sure about the 18S21 though. I think it is the same type of sensor as the 18S20 but with less accuracy.

NavMicroSystems

- 25th November 2005, 16:21

John,

could you post your schematic?

The problem is most likely a missing (or incorrect) resistor.
If you want to run the Sensor on "parasitic power" have close look at the datasheet regarding the timing.

BTW
I'm sure there are already several code examples on this forum.