Disassemble BYD's smart car key to see what solution it uses

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Disassemble BYD's smart car key to see what solution it uses [Copy link]

 

BYD's NFC car key frees car owners from the shackles of car keys. Many car owners say that after getting an NFC car key, they basically forget to bring their car keys with them, which is very cool. What solutions are used to make those car keys that are gradually "forgotten"? This article will take you to take a look.

The author found a BYD car key in the drawer and thought of taking it apart to see what design it was made of.

The prying process went very smoothly. Let’s take a look at the main control first.

The first chip I saw was an NXP chip, model FA7952A15, SSOP24 package, which is a dedicated automotive-grade wireless IC and also a type of RFID technology. After checking the information, I found that this is a solution called PEPS technology, which is a new generation of anti-theft technology. After being equipped with this solution, it is no longer a traditional key, but a smart key. When the driver enters the designated range, the system will identify and judge. If it is a legally authorized driver, the door will be opened automatically. After getting in the car, the driver only needs to press a button to start the ignition.

The recognition accuracy is relatively high, with a range of <5cm, ultra-low power consumption, a battery life of more than 2.5 years, and the response is also very fast.

Here’s how it works:

The following is a wireless transmitter chip, model RF211, RF112 has a built-in button detection automatic shutdown function, extremely low standby power consumption, and has output overcurrent protection, over-temperature protection, undervoltage abnormal protection and other functions. The standby current is only 0.1uA, and it can be powered by a 2032 button battery. Users can choose 2260 encoding or 1527 encoding. Select 1527 encoding, no need to manually set the address, each chip has a unique encoding address, and 1 million sets of encoding are not repeated. RF112 has internal SAW frequency stabilization, stable performance, SMD packaging, ultra-small size, no peripheral parts, no need for debugging, and very high cost performance.

You only need to add a button and a matching network antenna with 2 inductors and 3 capacitors at the antenna output end to make a wireless remote control that meets FCC certification and other standards.

The schematic diagram is as follows:

As for the button battery model, it is Panasonic CR1632, and the quality is excellent.

I can't find the model of this black component online, so I guess it's a 125KHz induction receiver, or a 3D one? If you see it marked with XYZ, please share it in the comments section.

Finally, a family photo

(This article is transferred from the official account Chip Home)

annysky2012

I tried to make one myself before, with an STC microcontroller, but I found that using a button battery didn't work.

tagetage

Which company's product is RF211?