In this post we find out about a basic infrared based remote control door lock circuit that are available for securely locking doors by means of unique foolproof IR frequencies.
The suggested infrared remote control circuit can be utilized for locking your main door, gate, garage door, shop or any entrance which can require a quick and easy internal locking by means of a remote control system.
The above diagram demonstrates an ordinary IR based remote receiver design, during which the IC LM567 forms the IR frequency decoder while the IC 4017 forms the flip flop stage.
D1 is a photodiode sensor which transforms the IR frequency from the IR transmitter into a in the same way pulsating voltage across R2.
This pulsating voltage is felt and acknowledged by the pin3 of the IC LM567, if the frequency of the pulse suits with the fixed frequency of the IC it immediately triggers its output pin8 with a low logic pulse.
The IC frequency is fixed by choosing R1/C1 properly which turns into the unique code of that specific remote control method. Any specific value between 10 Hz to 500 kHz might be set utilizing these RC timing components of the IC.
When a matching frequency is identified across R2, pin8 of the LM567 is offered with a low signal.
This causes the attached BC557 delivering a positive pulse to pin14 of the IC 4017.
Pin14 being the clock pin of the IC 4017 produces a resulting shifting high across its demonstrated outputs, based on the initial status either a high or a blank signal is produced at the base of the connected BC547 relay driver stage.
This permits the relay to toggle over the specific position forcing the solenoid device towards a locking or an unlocking position.
C3 is specially launched with the intention to delay the reaction of the relay toggling, this means that the isolated transmitter will have to be pressed for a few seconds to be able to apply the above locking/unlocking methods. This guarantees that an intruder or a hacker struggles to affect the Rx by means of a varying/sweeping frequency producing device.
The following image demonstrates the IR transmitter handset for the above RX unit, which turns into the remote control handset for locking or unlocking the door.
The above Tx is a basic RC based two transistor oscillator, which can be utilized as the Tx remote handset for the offered IR door lock circuit.
The 3V is utilized by means of a push button switch activating the pulses through the IR diode towards the photo diode of the above described Rx circuit.
Within this Tx circuit also the R and C components needs to be appropriately chosen such that the transmitted frequency distinctly suits with the set frequency of the Rx circuit.
The appropriate formulas might be analyzed in the following article
http://homemadecircuitsandschematics.blogspot.in/2015/02/infrared-remote-control-security-lock.html
After assembling the circuits the units might be analyzed externally to verify the relay toggling as a reaction to the Tx IR frequency.
As soon as this is achieved, the Rx circuit might be surely enclosed inside a sturdy box and built-in with the door from the interior for the meant locking/unlocking
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