Pairing Low Power RF based Modules with Key-less Entry Systems


  • At nominal usage, the designed circuit is claimed to run for 4 years on a single battery 
  • The design can be efficient for RKE Systems developed for Automotive and Automation industries.

In this era of technologies, the Remote Keyless Entry (RKE) system has become an integral part of motor vehicles and Smart Homes. The Remote Keyless systems generally consist of a wireless transceiver pair or an RFID based tag which transfers data when it comes in the communication range. In the case of RFID based systems, they utilise the transmitted power collected through the antenna and sends a unique identification code resulting in the activation of secured systems.

Design Schematics
Design Schematics

The design is based on the design and development of 433 Mhz based transceiver pairs which can be widely used in portable keyless entry based systems designed for automobiles and home automation.

Low power-based modules

The transmitter and receiver modules are based on low power consumption technology which reduces the power consumption in battery-driven devices. The TX-RX pair works in an operating voltage of 2 Volts to 3 Volts with a working current consumption of 6.8 milliamperes. This helps in stretching the battery life of the device for years even in small coin cells. The board is equipped with LED indicators with limiting resistors for indicating the active state of the device. The device developed by the design is claimed to be working for over 4 years on a single battery in nominal use.

A wide transmission range over 200 meter


The design has a compact form factor of 4.5 cm x 3 cm. While working on a low power configuration, the TX-RX pair is able to provide a long-range communication up to 200 meters maintaining the height of the antennas to be below 1 meter. The designed system has an overall gain of -30 dB and a receiver sensitivity of -114dBm.

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The firmware uses Manchester Coding for the data communication between the TX-RX pair. It provides an easy interface to do encryption in the programming phase only. The pair comes with an onboard SMA connector for easy interface with Gain based antennas.

The design has been released and developed by Maxim Integrated Technologies and the design includes all the necessary documents for open-source prototyping of the circuit. All the technical documents can be downloaded here.




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