Disasters and mishaps arrive when you are least expecting them. In today’s day & age, proper home security is a must for everyone. Smart door locks function as the very first step in an effective home security setup. In today’s article, we will look into a step by step process on ‘How How To Make A Smart Door Lock’ using An IR Receiver & a Servo Motor.

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PCB Prototype 2$

Step 1: Hardware Required

NE555 Timer IC
Op-Amp IC LM358
NPN Transistor 2n2222
Servo Motor
Relay Switch
IR Emitter LED
IR receiver TSOP1738
LED
Potentiometer
Capacitors
Resistors 10K, 68K, 33K, 4.7K, 1K, 560 Ohm, 220 Ohm
Soldering Iron
Diode 1N4007
Soldering Wire with Flux
Veroboard
DC Battery with Clip
Male Header pins
Jumper Wires

Step 2:

Solder the pin 4 & 8 of the 555 timer IC on the vero board.

Step 3:

Solder a 33K Ohm resistance between pin 7 & pin 8 of the timer IC.
After that solder a 68K resistor between pin 6 & 7 of the timer IC.

Step 4:

Solder two 100 pF capacitors from pin 2 to pin 1 and pin 1 to pin 5 of the timer IC.

Step 5:

Solder the emitter of the 2n2222 transistor to pin 1 of the IC. After that, solder a 4.7K resistor between pin 8 & the collector of the transistor.

Step 6:

Solder a 5V relay on the Vero board & solder a 10K resistor between pin 6 & NO terminal of the relay.

Step 7:

Solder male headers for servo & LM358 Op-Amp on the veroboard

Step 8:

Solder the 10K pot & a 10K resistor between pin 4 & 3 of the Op-Amp.

Step 9:

Solder a 1N4007 Diode between relay coil pins. After that, solder it to the collector of the 2n2222 transistor with emitter soldered to pin 4 of the LM358 IC.

Step 10:

Connect a 220 Ohms resistor from pin 1 of the op-amp to +ve terminal of the LED & connect a 560 Ohm resistor from pin 1 of the op-amp to the base of the transistor. Connect the LED +ve to pin 1 & -ve to pin 4 of the op-amp.