特斯拉PET钥匙-蓝牙无钥匙

Model 3 的 PET 钥匙和 Security Controller

现在卖车，要有卖点要从客户角度来思考，要营造一些高级感。这方面特斯拉玩得特别溜，绑定特斯拉 APP 的手机，带着手机靠近车门即可打开车门、坐进车里就可以把车开走，关门离开车之后过一段时间车就自己上锁。或者使用很有特点的 Key Card，给人身份感的接入方式，这事本质和我们的 PEPS 差不多，就是不用给钥匙换电什么的了。我们接下来通过原理图来看一下这个 Security ECU 的设计。

整体概览

传统的无钥匙进入&一键启动，PEPS（Passive Entry & Passive Start，）需要车外的定位，通过门把手的低频天线来实现；进入到车里面之后进行启动、动力防盗认证，需要车内的定位。Model 3 为左右 B 柱各 1 根、车内 1 根共 3 个蓝牙的模块，然后做了两个 RF 读卡器（一个整合在 B 柱里面，一个整合在 Security controller 里面）

Tesla provides a key card that communicates with Model 3 using short range radio-frequency identification (RFID) signals. The key card is used to “authenticate” your phone to work with Model 3 and to add or remove other key cards, phones, or key fobs.

如下图所示，这包括 BCM 给一路高边开关给这个 BLE Driver 进行供电，然后一路独立的 CAN 通到 Security ECU。

这个 Security ECU 主要承担分别读取三路 BLE 读卡器的 CAN 数据，然后处理完发送给 Vehicel CAN 总线，有两个 Security ECU（A&B）进行读取和发送。

这个 ECU 的连接器之前冬瓜也写过，我这边根据这个原理图重新理了一下。如下所示：

Security ECU 内部

通过美国的官方网站可以找到这个部件的内部图片，我搬过来，大家可以参考下，我没仔细拆过这个部件，不过根据叙述，这个 Security controller 的功能主要是在驾驶的时候确认这个钥匙在位置上，所以也叫 Central Security Controller，具备读 NFC 卡和蓝牙的功能。

1）正面

2）反面

反面的主芯片看不清，这里的数据都是通过这个主芯片处理完再发出去。

这个防盗机制，也在特斯拉给 NHTSA 的信息里面有所涉及

备注：Passive entry transponder (PET)就是这个 Key 钥匙

Tesla explained that its antitheft device will have a two-step activation process with a vehicle code query conducted at each stage.

The first stage allows access to the vehicle when an authorization cycle occurs between the PET and the Security Controller, as long as the PET is in close proximity to the car and the driver either pushes the lock/unlock button on the key fob, pushes the exterior door handle to activate the handle sensors or inserts a hand into the handle to trigger the latch release.

第一阶段

During the second stage, vehicle operation will be enabled when the driver sits in the driver’s seat and has depressed the brake pedal. The driver can then move the gear selection stalk to drive or reverse. When one of these actions is performed, the security controller will poll to verify if the appropriate PET is inside the vehicle. Upon location of the PET, the security controller will run an authentication cycle with the key confirming the correct PET is being used inside the vehicle.