Automatic corridor light circuit with self-locking function

The author installed an automatic light in the corridor at the door of my home. It can automatically light up when someone passes by, automatically turn off after the person leaves, and stop working during the day. It is not only convenient and energy-saving, but also has the function of preventing theft and deterring. In the production practice, the author found that ordinary light control circuits have some shortcomings. Ordinary light control circuits have certain requirements for installation. The photoresistor needs to be separated from the lamp by a long distance, otherwise the light will interfere with the light control after the light is turned on. The circuit makes the light flash. Therefore, in actual use, the power of the light bulb cannot be too high, and the lighting sensitivity of the debugged circuit is always too high. For this reason, the author made some changes to the light control circuit so that once the lamp is lit, it will automatically lock in the lighted state and will no longer be interfered by the lamp itself. Working principle: The power supply part consists of C1, C2, R1, DW, and D to form a typical capacitor step-down circuit, which provides a stable +11V DC voltage. TX982 is a microwave induction control module. It uses microwave Doppler technology to establish a micro-electric field in a certain space. When someone or a moving object enters the electric field, it will reflect the echo and detect an extremely weak frequency shift after mixing with the electronic circuit. signal. After intelligent processing, this signal can output a control signal. Due to the use of a dedicated microprocessor for microwave detection, the pulse frequency and pulse width of the input signal can be processed, thus minimizing interference from small animals, distant trees, high-frequency communication signals, long-distance lightning and electrical switching. The detection circuit composed of infrared, ultrasonic and pyroelectric elements cannot be compared with conventional microwave circuits. In actual use, the false alarm rate is extremely low. When the microwave circuit detects someone moving within the monitoring range, the output end of the microwave induction control module outputs a pull-down level, causing the T1 tube to cut off, and point A changes from low level to high level. A light control circuit composed of 555 circuits start working. When the ambient light is very weak, the voltage dividing point between the photoresistor and R4 is lower than 1/3Vcc, the 3rd pin of the 555 circuit outputs a high level, the thyristor BCR is turned on, the bulb emits light, and at the same time the 3rd pin of the 555 circuit is at a high level. The T2 tube is turned on, and point B is forced to a low level. Only after the person within the monitoring range leaves, the triode inside the output end of the microwave induction control module is cut off, and the T1 tube is biased by R2 and is in a conducting state. A The point potential is at low level, the 555 circuit is reset, pin 3 becomes low level, the light goes out, the T2 tube is turned off, and the circuit exits the self-locking state and is ready to enter the next working cycle. Since the improved circuit has superior anti-interference performance, the control can be installed in the common ceiling-type corridor lamp shade, leaving no trace on the outside and having anti-vandal function.