Conventional Gauges in Car Dashboards
The gauges of different car dashboards are different, but the conventional gauges of general cars include a speedometer, tachometer, oil pressure gauge, water temperature gauge, fuel gauge, charging meter, и т. д.. In modern automobiles, automobile instruments also need to install voltage regulators, which are specially used to stabilize the voltage of the instrument power supply and suppress the fluctuation range to ensure the accuracy of automobile instruments. Кроме того, most of the instrument display is based on the sensor, and the sensing device changes its resistance value according to the state of the monitored object, which is expressed by the instrument. The most conspicuous thing in the dashboard is the speedometer, which indicates the speed of the car in km/h. The speedometer actually consists of two tables: one is a speedometer and the other is an odometer.
Classification of Automobile Instruments
The automobile instrument is composed of various instruments and indicators, especially the driver’s warning light alarm, и т. д., to provide the driver with the required automobile operating parameter information. According to different working principles of automobile instruments, it can be roughly divided into three generations:
- The first generation of automobile instruments is a mechanical movement watch.
- The second generation of automobile instruments is called an electric instrument.
- The third generation is a fully digital automobile instrument, which is a networked and intelligent instrument with more powerful functions and display content, and simpler wiring harness links.
Automobile Meters and Displays
Automobile meters are mostly third-generation meters, which can drive the base meter pointer through a stepper motor. You can also use the LCD screen to directly display graphics or text information. В то же время, it also has an intelligent processing unit, which can exchange information with other control units of the car.
Optoelectronics Display Instruments
The function of the car instrument is to obtain the required data and display it in a suitable way. The previous instrument is generally limited to 3-4 quantity display and 4-5 warning functions, now the new instrument has about 15 quantity display and about 40 warning monitoring functions. Different information is obtained in different ways and displayed. В настоящий момент, there are three main ways to obtain new instrument information: transmission through the body bus, conversion through A/D sampling, and acquisition through IO status changes.
For the display mode, there are mainly five modes:
- Drive the ruling rotation by driving a stepper motor.
- Display graphics or digital information through the dot matrix LCD display.
- Display through segment LCD screen or digital tube.
- Display through the switch of LED lights.
- Indicate the current status through different beeps of the buzzer.
Design Composition of Automotive Instrument Panel
According to the above requirements, the automotive instrument panel designed in this article consists of an MCU system, stepper motor drive LED display, LCD display, alarm function, memory function, key processing, LIN bus communication, low-speed fault-tolerant CAN bus communication, and power supply.
PCB for Automobile Instruments
Different cars have different meters. But the general automobile’s conventional instrument has the speedometer, the tachometer, the oil pressure gauge, the water temperature gauge, the fuel gauge, the charge meter, и так далее. UGPCB provides a high-quality PCB for automobile instruments.