Park-Aid


Posted on Feb 4, 2014

This circuit was designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm. , D7+D6 illuminate at about 10 cm. and D7+D6+D5 at about 6 cm. In this manner you are alerted when approaching too close to the wall. All distances mentioned before can vary, depending on infra-re


Park-Aid
Click here to download the full size of the above Circuit.

d transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc. IC1 forms an oscillator driving the infra-red LED by means of 0. 8mSec. pulses at 120Hz frequency and about 300mA peak current. D1 & D2 are placed facing the car on the same line, a couple of centimeters apart, on a short breadboard strip fastened to the wall. D2 picks-up the infra-red beam generated by D1 and reflected by the surface placed in front of it. The signal is amplified by IC2A and peak detected by D4 & C4. Diode D3, with R5 & R6, compensates for the forward diode drop of D4. A DC voltage proportional to the distance of the reflecting object and D1 & D2 feeds the inverting inputs of three voltage comparators. These comparators switch on and off the LEDs, referring to voltages at their non-inverting inputs set by the voltage divider resistor chain R7-R10. Power supply must be regulated (hence the use of IC3) for precise reference voltages. The circuit can be fed by a commercial wall plug-in adapter, having a DC output voltage in the range 12-24V. The infra-red Photo Diode D2, should be of the type incorporating an optical sunlight filter: these components appear in black plastic cases. Some of them resemble TO92 transistors: in this case, please note...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Power tool torque control
    Tech Toy Hacks
    Fire Alarm Circuit Using 555 IC
    oscillator HEF4060B counter doesnt count
    DDS SigGen PS
    Guitar pre-amplifier using uA 741
    Simple Metal Detector Circuit



    Top