Tilt Switch and Sensor: Advantages and Disadvantages

This page explores the advantages and disadvantages of tilt switches and tilt sensors.

Introduction

• Both tilt switches and tilt sensors serve the same function: to detect tilt or inclination. They become ON or OFF based on the degree of tilt.
• A tilt switch is an electromechanical switch, while a tilt sensor is an electronic device.
• Tilt sensors are classified as single axis/single output, dual axis/dual output, and dual axis/single output.
• Most tilt switches are SPST (Single Pole Single Throw) type, either normally open or normally closed.
• Mercury-based tilt switches are the oldest type, utilizing mercury’s excellent electrical conductivity. These switches use a blob of mercury in a glass bulb. When the bulb is tilted, the mercury makes contact with two leads, allowing current to flow when the switch is connected in series with a battery.
• Due to environmental hazards and regulations, mercury-based tilt switches are increasingly replaced by ball-type tilt switches or tilt sensors.

Figure 1 depicts both mercury-type and ball-type tilt switches. The advantages and disadvantages vary depending on the specific type of tilt switch or sensor.

Benefits/Advantages of Tilt Switches/Sensors

The following are the benefits and advantages of tilt switches and tilt sensors:

• Mercury-based tilt switch:
  • Low cost and easy to use.
  • Very long operating life.
  • Low resistance and quiet operation.
• Ball-type tilt switch:
  • Offers multiple contacts, allowing determination of tilt direction.
  • Less toxic compared to mercury switches.
• General Advantages:
  • Very small in size.
  • Consume low power.
  • Durable when used properly.
  • Easy to interface with microcontrollers for various analyses with simple code.

Drawbacks/Disadvantages of Tilt Switches/Sensors

The following are the drawbacks and disadvantages of tilt switches and tilt sensors:

• Mercury-based tilt switch:
  • Mercury is hazardous due to its toxicity.
• Ball-type tilt switch:
  1. Arcing may erode the contacts when the switch is subjected to current above its rated specification, reducing reliability.
  2. Vibration of the balls can create erratic or random signals.
• General Disadvantages:
  • Require gravity to operate (to roll a ball or move a blob of mercury). Therefore, they will not work under low gravity, reversed gravity, or zero gravity conditions.
  • Performance in vehicles that accelerate or decelerate suddenly may be unreliable.
  • Deliver erroneous results under significant vibration conditions.