如何將傳感器連接到汽車網(wǎng)絡

　　有一個廣泛的傳感器通過車輛使用，從溫度和觸覺傳感器加速度計和陀螺儀。本文著眼于傳感器網(wǎng)絡與有線網(wǎng)絡（如LIN、以太網(wǎng)和以太網(wǎng)）的接口，在擴展溫度范圍和更高電壓保護的汽車設計中。

　　現(xiàn)代汽車網(wǎng)絡使用不同應用程序的協(xié)議組合。車輛周圍的傳感器越來越多地被廣泛應用——從照相機的圖像傳感器到加熱和乘客識別的溫度傳感器——意味著不同的傳感器必須連接到不同的網(wǎng)絡。

　　本地互連網(wǎng)絡（LIN）是用于低成本的應用主要是在車身電子數(shù)據(jù)率通常是10到20 kbit/s，而控制器區(qū)域網(wǎng)絡（CAN）是用于主流的動力總成和車身通信高達10 Mbit / s的FlexRay總線是高速同步數(shù)據(jù)通信等先進的主動懸架系統(tǒng)。大多數(shù)車輛設計者使用大多數(shù)總線來傳輸更高性能的網(wǎng)絡，甚至50到100兆位/秒的視頻，盡管在車上也有100兆位/ s的以太網(wǎng)網(wǎng)絡來承載這些數(shù)據(jù)。

　　A key parameter for sensors to measure is temperature， as this can be used in many different ways to provide important information. The way the data is used， even for the same type of sensor， will require different bus interfaces. For example， an infrared temperature sensor such as the Melexis MLX90620 can be used as a ‘Thermal Comfort’ sensor in an automotive air-conditioning control system， but it can also be used for passenger classification and even for blind-angle detection. All of these applications would interface to different wired networks in the vehicle with different design requirements.

　　When the humidity in the car cabin is high and the temperature of the front windscreen is low， water vapor will condense on the glass， leading to an obscured view for the driver. The HVAC system can avoid this condensation by blowing dry hot air over the windscreen. For this， the system has to be able to detect condensation or even better， predict it. This can be done using IR thermometers， humidity sensors and external thermometers.