Sensor touch detection and electronics of the touch detection
The touch detection is an element of the traffic jam assistant system. With the help of a capacitive sensor system, the system records whether or not the hands of the driver are located on the steering wheel rim.
Hands on the steering wheel spoke or on the impact plate are not detected
The touch detection consists of the following components:
- Touch detection sensor
The sensor touch detection consists of a mat with a capacitive sensor system. The capacitive mat integrated in the steering wheel rim is connected to the evaluation electronics in the electronics of the touch detection.
- Electronics of touch detection
In the electronic component, the sensor signals are prepared, converted to digital signals and transmitted to the Body Domain Controller (BDC). The data is transmitted via the LIN bus. Possible fault states of the touch detection are stored in the fault memory of the Body Domain Controller (BDC).
By the changing of the capacity, the system detects whether or not the hands are located on the steering wheel rim. The electronic evaluation unit picks up the change and determines the corresponding status. If the hands of the driver are not detected on the steering wheel rim, the corresponding display for the traffic jam assistant lights up as an optical alarm. If afterwards the hands are not detected on the steering wheel trim again within a particular period, an acoustic alarm is activated in addition to the optical alarm. The traffic jam assistant system is also deactivated.
The evaluation electronics sends the status information in cycles to the corresponding control unit. If the sensor of the touch detection or the electronics of the touch detection is faulty, the traffic jam assistant system is automatically deactivated.
The following illustration shows the sensor of the touch detection and the electronics of the touch detection as an example. The exact installation position of the electronics of the touch detection depends on the series.
| Item | Explanation |
|---|---|
| 1 | Sensor of the touch detection, consists of a mat with a capacitive sensor system (only schematic diagram) |
| 2 | Electronics of touch detection |
| 3 | Line connection (mat with capacitive sensor system and electronics of the touch detection) |
| 4 | Plug connection three-pin (connection of wiring harness and LIN bus) |
| 5 | Plug connection two-pin (connection of touch detection sensor) |