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Parking assistance from the rear of the senses principle of

2017-08-15 03:39  
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This article describes the rear parking aid senses distance v principle. Parking aid senses distance barrier three led infrared signal buffering operation. Parking aid senses suitable for indoor use. LED D7 lighting when the bumper is approximately 20 cm from the wall. , D7 D6 irradiation of about 10 cm. And D7 D6 D5 approximately 6 cm. In this way, you are reminded that when approaching too close to the wall. All distances mentioned before can vary, depending on the infrared transmitter and receiver led and mostly affect the color of the reflective surface. Black surface greatly reduces the sensitivity of the device. Obviously, you can use this circuit in other applications (such as liquid level detection, adjacent equipment, etc. on the circuit, you can see: IC1 forms an oscillator driving infrared  LED  through 0.8 milliseconds. Pulses at 120 Hz frequency and peak current 300 mA. D1 and D2 placed on the same line facing the car, a pair of centimeters apart, in a system with good chopping short wall. D2 D1 extracted by the generation of the infrared beam reflected at the surface and placed in front of it The signal is amplified and peak detection IC2A to D4 & C4. diode D3, in R5 & R6, compensate for falling forward diode D4. reflect a dc voltage proportional to the distance of the object and D1 and D2 feeds the inverting input three voltage comparators. these comparator switches, light-emitting diodes in a non-inverting input voltage setting divider resistor chain r10 r7. use of the parking aid senses, you need to pay attention: The power must be standardized (thus the use of IC3) precise reference voltage of this circuit can be fed commercial wall plug power supply, a DC output voltage in the range of 12-24V. current drawing: led out of 40 ma; all led at 60 Ma @ 12 v DC supply. infrared photodiode D2, The type should be an optical sunlight filter: these components appear black plastic box. Some of them like TO92 transistors: in this case, please note that the sensitive surface of the curved, rather than flat. Avoid direct contact with sunlight or artificial light D1 and D2. If your car bumpers are black, you can compose infrared diode (white) license or number plate, which is sensible place to all circuits in the infrared emitting diode in a small box. 3 can be placed away from the main signal led box to make it in a highly visible car drivers. get close to the optimum setting D2 D1 (does not reflect the object) until D5 illuminates, then move a bit until D5 is clearly off. usually best distance d1 d2 is the range 1.5 - 3 cm If you need a simple circuit, this leadership to drive or relays, click on the level of infrared sensors.


Circuit diagram:


R1_____________10K 1/4W Resistor

R2,R5,R6,R9_____1K 1/4W Resistors

R3_____________33R 1/4W Resistor

R4,R11__________1M 1/4W Resistors

R7______________4K7 1/4W Resistor

R8______________1K5 1/4W Resistor

R10,R12-R14_____1K 1/4W Resistors

C1,C4___________1?F 63V Electrolytic or Polyester Capacitors

C2_____________47pF 63V Ceramic Capacitor

C3,C5_________100?F 25V Electrolytic Capacitors

D1_____________Infra-red LED

D2_____________Infra-red Photo Diode (see Notes)

D3,D4________1N4148 75V 150mA Diodes

D5-7___________LEDs (Any color and size)

IC1_____________555 Timer IC

IC2___________LM324 Low Power Quad Op-amp

IC3____________7812 12V 1A Positive voltage regulator IC