I finally got the Atlas Scientific conductivity sensor all wired up.
Turns out I have slightly misunderstood the documentation which says "temperature corrected reading". But it turns out you have to tell it the temperature and then it responds with an adjusted reading. Luckily I have a bag of LM35 temperature sensors. Of course, this does give me the problem of making it water proof but that should be too much trouble. I could be doing without the added complexity but hopefully it's not too much to extra. The datasheet says that its output is 0 mV + 10.0 mV/°C
The analogue in pin on the NXP is in the range 0-3.3v so if we use that raw it is the range 0-330°C which is an order of magnitude away from perfect, so I'm going to have to add an op-amp, they are only £1.88 for 5! I'm actually a little bit excited about this :)
The test code, as usual, is on my account at mbed.org
I have written code to read the sensor, and pump readings out to Ethernet when ready. It is time for bed so this will have to wait until a suitable time. I also need a stable5vsupply for the sensor so I have ordered so 5v regulators too, I think I have a couple of 5v zeners for now.
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