Tilt Sensor Introduction, Working, Types and Application

 Tilt Sensor

Tilt sensors are devices that produce an electrical signal that varies with an angular movement. These sensors are used to measure slope and tilt within a limited range of motion. Sometimes, the tilt sensors are referred to as inclinometers because the sensors just generate a signal but inclinometers generate both readout and a signal.


A tilt sensor is an instrument that is used for measuring the tilt in multiple axes of a reference plane. Tilt sensors measure the tilting position with reference to gravity and are used in numerous applications. They enable the easy detection of orientation or inclination. Similar to mercury switches, they may also be known as tilt switches or rolling ball sensors.

These instruments have become gradually more popular and are being adapted for increasing numbers of high end applications. For example, the sensor provides valuable information about both the vertical and horizontal inclination of an airplane, which helps the pilot to understand how to tackle obstacles during the flight. By knowing the current orientation of the plane, and the angle at which the plane is inclined to the earth's surface, stunt pilots, i.e. the Red Arrows, can put on a fascinating air show. Tilt sensors are an essential decision-making tool for the pilots.

Specifications of Tilt Sensors

The functionality of tilt sensors is influenced by factors such as gravity, vibration, temperature, zero offset, linearity, cross-axis sensitivity, acceleration/deceleration, shock, clear line of sight between the user and the measured point, and calibration of tilt sensors.

The key specifications of tilt sensors include:

  • Number of axes
  • The number of axes is an important factor as it varies from application to application.
  • In robotics, a dual axes tilt sensor is used. In video game controllers and joysticks, a three axes tilt sensor is required. In some smartphones, four axes sensors are used.
  • Resolution
  • The minimum inclination detected by the sensor.


The sensor's ability to react to small changes.

Measuring range

The range of inclination that can be handled by the sensor. Some sensors are capable of measurements of up to 10° while others can cover a range of up to 60°.

Noise tolerance

 Noise tends to cause harmonic distortions in the function of the sensor, resulting in output variation and a reduction of system efficiency. Manufacturer's guidelines regarding noise levels should be adhered to.


Vibrations can disrupt the sensor's functionality, and hence vibration resistance measures are required, especially when the sensors are used in harsh conditions; for example in off-road vehicles or construction sites.

Benefits of Tilt Sensors

  • The key benefits of tilt sensors include
  • Compact and simple to use
  • High resolution and accuracy
  • Very cost-effective
  • Low power consumption
  • Can be read by industry standard dataloggers

Working Principle

These sensors consist of a rolling ball with a conductive plate beneath them. When the sensor gets power, the rolling ball falls to the bottom of the sensor to form an electrical connection. When the sensor is tilted, the rolling ball doesn’t fall to the bottom so that the current cannot flow the two end terminals of the sensor.

A tilt sensor has a metallic ball that is designed to move the two pins of the instrument from the 'on' to the 'off' position, and vice versa, if the sensor reaches a pre-determined angle. Tilt sensors are the environment-friendly version of a mercury-switch.

Tilt Sensor Circuit

Required components for tilt sensor circuit

  • Tilt Sensor
  • 470 Ohms Resistor
  • Led or Load
  • DC Voltage Source

A basic circuit that uses a tilt sensor is shown below.

When the device gets power and is in its upright position, then the rolling ball settle at the bottom of the sensor to form an electrical connection between the two end terminals of the sensor. Next the circuit becomes short circuit and the LED gets sufficient current. If the circuit gets tilted so that the rolling ball doesn’t settle at the bottom of the sensor with the electrical conduction path, then the circuit becomes open. This is about the circuit operation.

Tilt Sensor Types

These Sensors are classified into different types and the classification of these sensors includes different devices and technologies to measure tilt, slope, elevation and inclination.

Force Balance Sensor

These sensors are gravity referenced sensors and are anticipated for DC acceleration measurements like ships, vehicles, aircraft and seismic events. These sensors are frequently used in inclinometers and tilt meters. Force balance sensors are capable of measuring levels from 0.0001g to 200g, and the frequency range is from DC to 1000Hz. The advantages of these sensors include their high accuracy, a change in broad measurement, insensitivity to temperature change and their high accuracy. The disadvantage of this sensor is its high cost.

MEMS Sensor

Solid state MEMS are small sensors as they consist of movable proof mass plates that are attached to a reference frame through a mechanical suspension system. This is a technique of combining mechanical and electrical components together on a chip to generate a system of miniature dimensions. Small means that the dimensions are less than the thickness of human hair. MEMS sensors are key components in many medical, industrial, aerospace, consumer and automotive applications. These sensors are used in anything from smart phones, gaming, medical tests and satellites. Steps to fabrication of MEMS involve the basic IC fabrication method.

Fluid filled Sensor

These Sensors can either be capacitive or electrolytic.

Electrolytic Sensor

The electrolytic sensor is used to measure an angle and the angle may be expressed in degrees, arc minutes, or arc seconds. Electrolytic sensors produce extremely accurate pitch measurements in many applications. These sensors easily maintain their high accuracy and small size. These sensors function by using cavity filled with fluid or a glass. The fluid performs between a common positive and negative electrode. When the electrolytic sensor is levelled, both the positive and negative electrodes get consistently submerged within the fluid and produce a balanced signal output. When the sensor is rotated, an imbalance is created between the two electrodes. So, the imbalance of any one of the electrodes is proportional to the angle of the rotation.

Capacitive Tilt Sensors

These types of sensors are designed to take non-contact measurements of inclination and tilt. These can operate both as switches and sensors. When the geometry of the capacitor is changed, the capacitor sensor relies on variation of capacitor. Here, the capacitive sensing is independent of the base material. These devices consist of a suspension beams, comb drive capacitors and central proof mass. When a tilt occurs, the central mass moves towards one of the combs so the capacitance increases at one side and decreases at the other side. The main advantage of the capacitive sensor is its performance ratio and cost-effectiveness, whereas a limited response is the main disadvantage of this sensor.


When selecting a tilt sensor, we should consider a few distinct specifications as shown below:

  • Number of Axes
  • Resolution
  • Measuring Range
  • Sensitivity
  • Noise Tolerance
  • Output
  • Vibration


  • To monitor the angle at which a mobile phone or tablet is held for the auto-rotate function
  • To detect the position of hand-held game systems and in game controllers
  • To indicate the roll of boats, vehicles and aircraft
  • To measure the angle at which a satellite antenna 'looks' toward a satellite
  • To estimate the height of a tree or building
  • To measure the steepness of a ski slope
  • To provide a warning system for the surface tilt angle of cryogenic liquids during transportation
  • To monitor laser levels and seismic activity


  • Cameras
  • Video Cameras
  • Aircraft Flight Controls
  • Construction Equipment
  • Robotic Technology
  • Automobile Air Bags
  • Videos Game Controllers
  • Studying Human Movement
  • Thermostats
  • Automobile Security Systems