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Re: [LUG] temperature sensors for Raspberry Pi brewery controller

 

On 09/11/12 10:04, 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?
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.

Robin

I am puzzled by this - many plastic wrapped kitchen probes offer 0.1% accuracy but are not suitable for automating but no-one seems to produce a suitable probe at anywhere near the price...
I think a hammer may be required.....
I want 0.1c resolution for OCD reasons as much as anything - though I will conduct beer mashing at that kind of accuracy out of interest...
Tom te tom te tom

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