Laser-guided Door Opener


This automatic door opener can be made using readily available
components. The electromagnetic relay at the output of this gadget
can be used to control the DC/AC door-opener motor/solenoid of an
electromechanical door opener assembly, with slight intervention in its
electrical wiring
A laser diode (LED1) is used here as the light transmitter. Alternatively,
you can use any available laser pointer. The combination of resistor R1 and
diode D1 protects the laser diode from over-current flow. By varying
muliturn trimpot VR1, you can adjust the sensitivity.
(Note that ambient light reflections may slightly degrade the performance of this unit.)
Initially, when the laser beam is falling on photo-transistor T1, it conducts
to reverse-bias transistor T3 and the input to the first gate (N1) of IC1
(CD4001) is low. The high output at pin 3 of gate N1 forward biases the
LED-driver transistor (T4) and the green standby LED (LED2) lights up
continuously. The rest of the circuit remains in standby state.
When someone interrupts the laser beam, photo-transistor T1 stops
conducting and transistor T3 becomes forward-biased. This makes the output
of gate N1 go low. Thus LED-driver transistor T4 becomes reverse-biased
and LED2 stops glowing. At the same time, the low output of gate N1 makes
the output of N2 high. Instantly, this high level at pin 4 of gate N2 triggers
the monostable multivibrator built around the remaining two gates of IC1
(N3 and N4). Values of resistor R8 and capacitor C1 determine the time period
of the monostable.The second monostable built around IC2 (CD4538) is enabled by
the high-going pulse at its input pin 12 through the output of gate N4 of
the first monostable when the laser beam is interrupted. As a result, relay
RL1 energises and the door-opener motor starts operating. LED3 glows to
indicate that the door-opener motor is getting the supply. At the same time,
piezobuzzer PZ1 sounds an alert. Transistor T5, whose base is connected
to Q output (pin 10) of IC2, is used for driving the relay. Transistor T6, whose
base is connected to Q output of IC2, is used for driving the intermittent piezobuzzer.
‘On’ time of relay RL1 can be adjusted by varying trimpot VR2.
Resistor R9, variable resistor VR2 and capacitor C3 decide the time period of
the second monostable and through iton time of RL1.
The circuit works off 12V DC power supply. Assemble it on a general-
purpose PCB. After construction, mount the laser diode and the phototransistor
on opposite sides of the doorframe and align them such that
the light beam from the laser diode falls on the phototransistor directly.
The motor connected to the pole of relay contacts is the one used in electromechanical
door-opener assembly.
If you want to use a DC motor, replace mains AC connection with a DC power
supply
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9 comments:

  1. thanx malikg157 ..we are happy that you like it.
    As soon as this Makeover is done, You will see even more interesting project,articles and video.
    stay connected " www.betaengineers.net "

    ReplyDelete
  2. IN THE CIRCUIT ,SPECIFY THE LASER DIODE NUMBER OR SPECIFICATION.

    ReplyDelete
  3. can u jst tel me tht exactly under which theme tis project cums..????

    ReplyDelete
  4. Whenever the light coming from laser get obstructed the Door will open

    ReplyDelete
  5. i need the documentation and report on laser guided door opener..can any 1 help me??

    ReplyDelete
  6. okkay ..i can mail you everything which is posted here and also what ever i have regrading this ..
    still want more try to search it on E4u

    ReplyDelete
  7. thank u but i need it immediately.. cn u pls forward me by tomorrow morning? vasavi491@gmail.com

    ReplyDelete
  8. can u please send me full report on laser guided door opener. Am working on the same project. tedbuckz@gmail.com

    ReplyDelete

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