The Inclinometer Sensor Head holds a five-pin glass tilt sensor. Inside the sensor is a conducting fluid. As the sensor tilts, the depth of the fluid in contact with the various pins changes, and the electrical resistance between the pins changes also. Because the surface of the fluid remains horizontal as the sensor tilts, the relative resistance between pins is a function of the inclination of the sensor.
When we measure the DC resistance between tilt sensor pins with a voltmeter, we get a measurement of a few Megaohms. But when we place the sensor in a voltage divider driven by a 1-kHz sin wave, we find its AC impedance is far lower: of order a 1 kΩ
Below you will see soldering instructions for the sensors. We found them to be robust to our usual 600°F soldering, and we did not have to tin the wires, because they came pre-tinned. We dropped the iron temperature to 500°F during production. You may find that your sensor leads are not tinned, in which case you will have to tin them with acid flux.
59560: Tilt sensor data sheet.
S2066_1: Connection for an Applied Geometrix five-pin glass sensor.
Applied Geomechanics: Company that makes the tilt sensor we use with the Inclinometer.
Inclinometer Head (A2065) Manual: Describes sensor electronics.
Soldering Instructions: How to tin the leads of the sensor, and how to solder it to the board once the leads are tinned.