Arduino Forum

Forum 2005-2010 (read only) => Software => Troubleshooting => Topic started by: bates.and on May 29, 2009, 01:00 am

Title: Using the Dallas Tempature Library
Post by: bates.and on May 29, 2009, 01:00 am
So I have a D18B20 tempature sensor that I am trying to use. I downloaded the Dallas Tempature Library from(for some reason can't post the link. I'm using Miles Burton's library linked to from the onewire page in the playground). I've been trying to run the example program and am getting "Invalid CRC". Unfortunately I'm not sure where to look for the problem.

I'm running Arduino - 0015 with a USB Arduino Duemilanove with an Atmega 328 processor. All of this on a mac OS x. I have the sensor connected to the 5v and ground and then the bus wire to port 12 with a 4.7k resistor.
Title: Re: Using the Dallas Tempature Library
Post by: GordonEndersby on May 29, 2009, 11:21 am
Is that a D18B20 or a DS18B20?

There are loads of posts on the forum on getting the DS18B20 working with the Arduino.
Including example code.

Try searching the forum using google it works better than the forum search tool.
http://www.google.co.uk/search?hl=en&q=site%3Aarduino.cc+DS18B20&btnG=Search&meta=

Gordon
Title: Re: Using the Dallas Tempature Library
Post by: bates.and on May 29, 2009, 07:28 pm
It's a DS18B20. I'm beginning to wonder if I have a bad chip because after reading multiple posts it seems that no one else is having this much trouble getting this sensor to work. Either that or I'm doing something drastically long. (I'm an ME guy not an EE or CS guy...)

Thanks for your help I think I will get a new sensor next time a place an order.
Title: Re: Using the Dallas Tempature Library
Post by: TeamMCS on May 31, 2009, 01:39 pm
Hi Bates,

the library was intentionally designed for the DS18B20 with other series playing supporting roles.

Have you made sure you've grounded the other pins and "pulled-up" the data wire appropriately?

What you've said is usually a sign of a badly wired up IC


*re-read your post*
You have 3 pins. ground the outer two. Pull-up the centre (as you are) and connect it to an appropriate pin