I just ordered my first Arduino and I wanted to tackle a project that I had thought for a while.
The project is to measure conductivity of a flowing water. I would like the input to then be transmitted to a mobile phone ( I also ordered BLE shield for my arduino).
The probes I see in the market are not suitable due to their shape. Therefore, I am looking on how to create a probe for both Salinity / Conductivity and Ph Measurement?
I would really appreciate any guidance on this as I have no idea where to start..
You cannot make a PH probe at home - you must find a PH probe (at least the business end of one) that can be used for your application.
A conductivity probe is tricky mainly because you need to prevent electrochemical corrosion. I don't know how the commercial ones do it. Maybe gold or platinum electrodes? There is probably a standard way of doing this though. You want to do it that way.
DrAzzy:
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A conductivity probe is tricky mainly because you need to prevent electrochemical corrosion. I don't know how the commercial ones do it. Maybe gold or platinum electrodes? There is probably a standard way of doing this though. You want to do it that way.
Cut 2 1x1 cm pieces of thin platinum metal. Rigorously clean them with 50% hydrochloric acid, then 10% nitric acid, and rinse them thoroughly with distilled water. Use a DC plater and plate with a 0.1M chloroplatinic acid to electoplate them. Use low current (0.01 amp) and do both electrodes at once, one on each pole of the plater - reverse the current every minute to make 2 electrodes. Once they are solid black, take them out of the plating solution and wash them.
Solder wires onto the corners of each one, and place them about 3 mm apart. Put them into the solution you wish to test. Measure the resistance between them. Prior to measuring your test sample, calibrate the electrode pair with several different concentrations of salt water.
For a pH meter, buy a cheap meter, like a Hanna, and hook it up through an op-amp. The probe will put out about a volt or so, at the extremes of it's range, so you will want to slightly amplify this to keep the noise low in the middle.