2 replies to this topic

[MattEric]

Anyone know anything about hooking up a pH sensor to Netduino? Trying to source, and then control, an in-line micro sensor. I've read a little about ISFET probes.

[CW2]

Anyone know anything about hooking up a pH sensor to Netduino? Trying to source, and then control, an in-line micro sensor.

You can have a look at phduino project for inspiration. pH meter is basically a millivoltmeter, pH probes (both glass and ISFET) output voltage depending on the value of pH (i.e. several millivolts per pH unit), so you need to amplify the voltage with operational amplifier circuit and then wire it to microcontroller analog input (A/D converter). For precise measurements, you'd also need calibration and temperature compensation.

[CW2]

I've read a little about ISFET probes.

You can get ISFET probes (and meters) at ISFETCOM (also note their claim about copycats). Depending on your usage scenario, you may need industrial grade probes (long-term immersion, food industry etc.), which are rather expensive...