A simple baffle-type solar position sensor is shown in figure 1. Two sets of partitions are installed vertically on the base, and the two partitions are perpendicular to each other. On the base is installed four photosensitive resistance device, four photosensitive resistance device to partition the corner installation, photosensitive resistance device receives upward, four photosensitive resistance device must be the same type, similar performance.
The diaphragm type sensor USES the light intensity on both sides of the baffle to determine the position of the sun, and the baffle of the sensor is arranged in the north-south direction, as shown in figure 2. When on the west side of the sun position in plate, on the east side of the light is blocked, as shown in figure 2 (left), the west side of photosensitive resistance by light quantity is greater than the east side of photosensitive resistance, resistance is less than the east west components resistance, and can determine the position of the sun in the west. And in a certain range, the greater the deviation of the light, the greater the difference in resistance.
Because the diaphragm is cross shape, clapboard type sensor can also detect the locations of the sun in the north-south direction, the four sensors signal after comprehensive comparison can be concluded that the position of the sun, such as the west by north.
For the solar panel single-axis tracking system, the sensor needs only a single partition plate, which is parallel to the axis of rotation. When the two sides of the resistance are not identical, the solar panel should rotate to the side of the resistance, until the resistance is the same.
The partition type sensor can also use silicon photodiode as photosensitive element, silicon photodiode is high precision, it does not belong to silicon photocell, also can choose to use silicon photocell. 4 silicon photodiodes are installed in the four corners of each other perpendicular to each other, as shown in figure 3, the position of the sun is determined by the difference of light area between the photosensitive elements on both sides of the baffle. Its working principle and using photosensitive resistance is the same, the intensity of the silicon photodiode weaker than by light of silicon photoelectric diode output current is large, using the convert current signal to voltage signal amplifier is convenient to compare. If you use a silicon photocell without power supply, you can directly output voltage and compare it. The circuit is simple.