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On Fri, 9 Nov 2012, Robin Cornelius wrote:
On 9 November 2012 09:54, tom <tompotts@xxxxxxxxxxxxxxxxxxxxxx> wrote:Someone recently mentioned the http://www.raspberrypi.org/archives/2129 brewery controller. The temperature sensors are +/- 0.5 C which isn’t accurate enough for my liking. Does anyone know of better ones?
Curious to know what you're doing that needs a more accurate measure of temperature...
The linked article says 0.1 degree resolution but clicking through they are using a DS18B20 with an absolute accuracy of +/-0.5 so are you after absolute accuracy better than 0.5 degree or better resolution? The best accuracy you are going to get is via a PT100 (RTD) but you will need some extra circuitry to drive one. There is a nice chip from analog devices that interfaces PT100s and you can just bit bang the serial interface via the GPIO on the pi, but i expect you are not going to find a 3 wire device such as the DS18B20 that just works with better accuracy.
It's a time & money problem. And it's not linear either... Gordon
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