手持式油位计

手持式油位计以超声波换能器作为传感器件，实现了油位的非接触测量；以单片机为主控器件，用光电耦合器将超声波发射电路与系统隔离，提高了系统的稳定性；接收部分采用集成锁相环LM567检测接收到的信号，降低了成本；使用单总线数字温度传感器DSl8820对声速进行补偿，对产生读出DSl8820数据错误的原因进行了分析并解决了这一问题；电源电路采用高效率芯片1CL7663，实现了单节干电池供电；显示采用液晶显示模块，减少了能耗；整个系统达到了设计的要求。

Handheld Type Oil-level Meter

In the handheld type oil-level meter, the ultrasonic sensor was used as transducer to detect the oil-level which was achieved by no contact; the stability was improved by using the MCU as the main controller and the optoelectronic coupler to separate the emitting circuit from the system; the cost is reduced by using the LM567 to receive the ultrasonic waves; the 1-wire bus digital tempera- ture sensor DS18B20 was employed to compensate the voice speed,the cause of the error when reading the device was analyzed and also the problem was solved; the high efficient chip ICL7663 was employed in the power supply circuit to achieved the single battery power supply; the LCD module was used in the display to reduce the energy consume. By all of above,the design requirements is achieved.