Ignition detection in Keys using Reed Sensors

In ignition detection in automobile, two primary types reign supreme: the traditional manual key and the more modern start button, favoured by newer vehicles equipped with keyless entry systems. Whether it’s the familiar twist of a key or the simple press of a button, the ignition switch serves as the gateway to activating the vehicle’s main electrical systems, thereby initiating essential functions such as engine start-up, power window operation, activation of parking lights, and control of the media player.

However, with convenience comes the potential for oversight. In the event that the driver inadvertently leaves the vehicle with the ignition or accessory systems engaged, the consequences can range from a drained battery to the risk of theft. To mitigate such risks, sophisticated ignition detection systems come into play.

Utilizing seat sensing technology, these systems monitor the driver’s presence and activity within the vehicle cabin. When the driver attempts to exit the vehicle while the ignition detection or accessory systems are still engaged, a network of sensors collaborates with a microprocessor to trigger an audio-visual alarm, alerting the driver to the oversight.

Furthermore, to prevent unauthorized use of the vehicle, additional layers of security are implemented. A reed sensor and magnet setup discreetly installed beneath the driver’s seat detects changes in seating position, automatically deactivating when the driver vacates the seat. Similarly, another reed sensor and magnet arrangement assesses the position of the ignition key, ensuring that power is cut off from the vehicle when the key is removed.

Application Classification

Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.

Position sensing Type

When an application requires the end position of a movement sensed, or the sensing of a part when it comes into a zone, or when the Continue reading -> Jul 14, 2025

Recommended Products

The Reed Switches and Sensors used in this ignition detection application needs to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.

Ultra Miniature Reed Sensors, R5

R5-J SMD Reed SensorR5-J Reed Sensor PCB Layout drawingR5-J Carrier TapeR5-S SMD Reed SensorR5-S Reed Sensor PCB Layout drawingR5-S Continue reading -> Jun 18, 2025

Ultra Miniature Reed Switch, UM-0018-M

Full Length LeadsCropped LeadsSMD formed LeadsFormed Leads for Horizontal mountingFormed Leads for Vertical Mounting starFeatures 5.0 Continue reading -> Jun 18, 2025

Ultra Miniature Reed Switch, UM-0018-H

Full Length LeadsCropped LeadsSMD Formed LeadsFormed Leads for Horizontal MountingFormed Leads for Vertical Mounting starFeatures7.0 Continue reading -> Nov 30, 2024

Ultra Miniature Cylindrical Magnet Sensor, MS-212

MS-212 Magnet Sensor Drawing starFeatures10W Contact Rating. Normally Open contact. Two sensitivity bands. Sputtered Ruthenium Continue reading -> Jun 18, 2025