Letter Box Indicator

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Rs. 980.00
Ex Tax: Rs. 980.00
  • Price in reward points: 9
  • Brand: Orion iTech Solutions
    Product Code: SB01/EC119

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    The letter box is used in every house and post office so we aim at building an electronic indication system which will tell us whether the letter box is empty or not. 
    This electronic postbox indicator is build using a 555 timer and LDR which senses the presence of letter and indicate accordingly by using buzzer and led.

    When letter drop by someone into the letter box then the LED attached at the output stops blinking which indicates that there is a letter in your letter box. To identify the presence of a letter in the box we have connected a LDR as well as source of light. 

    LDR is a special kind of resistor whose action based on the intensity of light declining on it. In the time of total darkness LDR resistance is approx. 1 mega ohm while at the time of bright light its resistance is 2-5 ohm. 

    In this circuit the light source is adjusted with the LDR in such a way that the light will directly drop on the LDR so that when any letter comes inside the letter box it will chunk the light beam and LDR will be beneath darkness.





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    Q1. Where we can use this project?
    Ans1. We can use this project to control gates of any premises, organization, building etc. It senses the vehicle and automatically opens the door.
     Q2. Which sensor is use to detect vehicles?
    Ans2. LDR is use to detect the vehicle. If any vehicle comes near the gate LDR senses it and open the door.
    Q3. Why LM358 IC is use in this project?
    Ans3. LM358 is use in this project to convert analog output of  LDR into digital output for microcontroller.
    Q4. Why crystal oscillator is use with microcontroller?
    Ans4. A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency.
    Q5. What is the frequency of crystal oscillator?
    Ans5. The frequency of crystal oscillator use in this project is 11.0592MHz.