| As the development of auto industry and improvement of people’s living standard, more and more auto windshield blocks ultraviolet and infrared rays by the way of coating. However, there are many unqualified glass films in the market presently. These fake products seriously damage the safety of people. Therefore, designing a portable and highly accurate tint meter is the market’s requirements.This paper aims to develop a portable tint meter which can meet requirements of measuring. It has established an improved light intensity detecting method based on diffuse reflection. The method expandes the types of glass detected and is able to detect front and back windshield which can not move. Compared to the tint meter existed in the market, on the premise of meeting measurement accuracy, this design can reduce costs and volume.The design uses a SCM as microcontroller, keeping a real-time record of environmental light intensity. This can eliminate the influence of outside light on the measurement accuracy and improve anti-environment interference capability.In view of being portable battery-powered system, the design can reduce power consumption by the way of selecting components and software programming. Finally, the life of battery can be extended to 130 hours above.Using computer software to do calibration improves the efficiency of the detector manufacture in mass production.After doing some experiment, it can draw the following conclusions: 1.The lit time of LED is the key factor of affecting repeat precision. When the LED lit time is extended to 5 seconds, degree of dispersion of measuring data will increase by 1.2 times. 2. Misalignment of the two parts of tint meter don’t affect the accuracy but repeat precision.After using least-squares method of fitting calibrating the dector, the deviation between standard and detecting data is in range of 1.5%. It can meet the requirements of operation. |
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