What is a Smart Key?
3 Answers
Smart key is a device that uses infrared signals to unlock one or two doors, the trunk, and the fuel tank cap, and can also control the car's windows and sunroof. Principle of Smart Key: Smart keys can be divided into two parts: the entry system and the start system. However, most keyless entry systems include the start function, with only a few models featuring the entry function alone. The smart entry system utilizes the most advanced RFID (Radio Frequency Identification) technology. RFID is a non-contact automatic identification technology that automatically identifies target objects and retrieves relevant data through radio frequency signals, requiring no manual intervention and capable of operating in various harsh environments. In other words, when the owner approaches the vehicle within a certain distance, the door locks will automatically unlock and disable the anti-theft system; when the owner leaves the vehicle, the door locks will automatically lock and activate the anti-theft system. However, to prevent situations where the smart card is damaged or out of power, rendering the owner unable to enter the vehicle, a traditional keyhole is still retained on the door handle. Smart Key: Smart keys were first introduced by German Mercedes-Benz sports cars. Externally, a smart key resembles a card, making it very convenient to carry, especially at night when the driver can unlock the car simply by touching the door with the smart key. Although smart keys are convenient, once they malfunction, it can be very troublesome, as they may not only prevent the car from starting but also make it impossible to open the doors.
The smart key is essentially a nifty gadget that makes driving more convenient, and I've been using it for several years. Unlike traditional keys that need to be inserted into the lock, you just keep it in your pocket, and the car automatically unlocks as you approach. Once inside, press the start button to ignite the engine. Losing it isn't a big worry either, as the car recognizes specific signals, and getting a replacement key requires decoding at an authorized 4S store. Just remember not to place it near your phone to avoid electromagnetic interference that might cause malfunctions. On rainy days, locking the car is quicker by simply touching the sensor area on the door handle instead of fumbling for a key. Nowadays, you can even use an app for remote unlocking—like that time my neighbor's kid got locked inside, and I opened the door straight from my phone. It's incredibly practical.
We in automotive design call this thing a keyless entry system, which is essentially an electronic key with a chip. The principle is quite simple: the key emits a low-frequency signal, and the car's antenna receives it to verify the password. By the way, its battery typically lasts only two to three years. I always keep CR2032 coin cells in my garage drawer—just pop open the back cover to replace it. Retrofitting older cars requires caution, as you’ll need to add a control module, which might compromise circuit safety. Once, I lent my car to a friend who walked about a dozen meters with the key in his pocket before it auto-locked, so it’s best to shorten the sensing distance in the settings. Also, avoid placing it near microwaves or magnets, as they can reset the program.
