Inclinometers, alternatively known as gravitational or tilt sensors, measure an angle from the direction of Earth's center of gravity. The words “tilt sensor” are often used to describe a tranducer of tilt specifically using gravity as a reference (Puccio 2004).


Mercury switches, used for instance in Michel Waisvisz's "The Hands" (Waisvisz, 1985), are examples of on-off tilt sensors. One commercial example is the TiltOn, a mercury switch-based single axis inclination sensor supplied by Infusion Systems.

Examples of sensors measuring continuous inclination include electrolytic tilt sensors. These sensors typically consist of an electrolytic fluid (electrolyte) partially filling a tube with three electrodes (one-axis sensors) or five electrodes (two-axis sensors) at its base. When tilting the online bet sensor, the electrical resistance between the center electrode and the electrodes at the periphery will vary proportionally to the tilt angle.

Examples of commercial continuous inclination sensors exist with ranges between ± 1º to ± 80º (The Fredericks Company).

Other implementations of continuous inclination sensors may use an LED and arrays of photodetectors (Fraden 2004, pp. 258).

Finally, accelerometers, with sensitivities around a few g (1 g = 9.8m/s2), can also be used to measure inclination. One example is the ADXL 105 (one axis, ±5 g) or the ADXL 202 (two axes, ± 2 g) or the Memsic 2125GL 2-axes thermal accelerometer (also with a ±2 g acceleration measurement range).


Omron Electronics Inc D6B-1
Sources Digikey CAN$ 17.99
Description Surface mounting micro tilt sensor.
Datasheet D6B.pdf
Notes 35 to 65 degrees tilt.
Fredericks Company TrueTilt Sensor 0717-4304
Description Continuous output inclinometers
Datasheet 4304 Datasheet
Resources General info from manufacturer
Notes Electrolytic Tilt Sensor. Range: ± 60˚
Variants narrow (up to ± 5˚), mid (±3˚ to ±25˚), or wide range (up to ± 180˚, with a linear range of ± 80˚; single axis; on-off.
Spectron Dual Axis Electrolytic Tilt Sensors - SP5000 and AU6000 Series
Sources Spectron
Description Dual axes, various ranges (± 20˚ to ±70˚)
Resources Spectron Glass and Electronics Incorporated - Electrolytic Tilt Sensors
Variants single axis.