How To Make A Wireless Doorbell Circuit Using A 433 MHz RF Transceiver

Wireless Doorbell

The use of old and traditional doorbells which generally run a wire to your AC mains is slowly becoming obsolete due to a number of reasons. Firstly, the wiring itself is a running electrical and fire hazard. In case the wiring terminals and the doorbell casing start taking on moisture, for example in rainy weather. Anyone who touches the doorbell is likely to receive a nasty shock which can be fatal in case necessary protections are not installed. Secondly, wired doorbell networks are unreliable and can cause a decent of frustration and confusion in terms of troubleshooting. So, in today’s tutorial, we are going to go over a step by step process on How To Make A Wireless Doorbell Circuit Using A 433 MHz RF Transceiver Module.

The main part of this wireless doorbell is a 433 MHz RF TX – RX module. Radio frequency (RF) detection module is a 433MHz trans-receiver module with a SAW resonator at its heart tuned for 433 MHz operations. It is utilized to transmit and receive radio signals between two devices on the same frequency levels. The transmitter drains no power while transmitting logic 0 while fully repressing the carrier frequency, hence consuming low power. When logic one is sent carrier is fully on to about 4.5mA with a 5V power supply. Data is transmitted serially which is then received by the receiver tuned to the same frequency as the transmitter.

Hardware Components

You will need the following parts to build this project:

S.No	Component	Value	Qty
1)	RF Transceiver Module	433MHz, 4.5mA	1
2)	Pushbutton	–	1
3)	Buzzer	9V	1
4)	Enameled Copper Wires	–	22AWG, 1/2 meter
5)	LED	5mm, 3.5V	1
6)	Soldering Iron	45W – 65W	1
7)	Soldering Wire With Flux	–	1
8)	DC Battery	9V	2
9)	Battery Clips	–	2
10)	Jumper Wires	–	As per need

433 MHz RF Transceiver Pinout

Buy On Amazon

Key Features & Specifications

Wireless (RF) Simplex Transmitter and Receiver
Transmitter Operating Voltage: +5V only
Transmitter Operating current: 9mA to 40mA
Operating frequency: 433 MHz
Transmission distance: 3 meters (without antenna) to 100 meters (maximum)
Modulating Technique: ASK (Amplitude shift keying)
Data Transmission speed: 10Kbps
Circuit type: Saw resonator
Low cost and small package

Useful Steps

Transmitter

1) Solder the 433 MHz transmitter on the veroboard.

2) Coil up an enameled copper wire to form an aerial antenna (up to 15 turns). After that, solder the aerial antenna with the RF transmitters ANT pin.

3) After that, solder a pushbutton between the Vcc and Data pin of the RF transmitter.

Receiver

1) Solder the 433 MHz receiver on the veroboard.

2) Coil up another piece of enameled copper wire to make an aerial antenna and connect it to the ANT pin of the RF receiver.

3) After that, Solder the +ve terminal of LED with both DATA pins of the receiver and the -ve pin with GND of the circuit.

3) After that, solder the +ve terminal of a 9V Buzzer with the DATA pin of the receiver and the -ve terminal with the GND of the circuit.

4) Connect the +ve & -ve pins of the battery clips with the Vcc & GND terminals of both RF transmitter & receiver respectively.

5) Power up and test the circuit using 9V batteries.

Working Explanation

The working of this circuit is pretty simple. In the first stage, on connecting the transmitter to power and pressing the pushbutton, a 9V signal acts as control input at the data pin of the RF transmitter. On receiving the control input, the transmitter’s oscillator starts producing a constant RF output carrier wave at 433 MHz that is picked by the receiver module.

In the second stage, on the receiver’s end, an RF tuner circuit obtains the transmitter’s input and passes it through an amplifier. After that, the signal is fed to a PLL circuit (phase locked loop), which allows the RF decoder to lock on to the stream of desired digital bits in order to gain a better decoded output and noise immunity. The output from the RF receiver is then fed to a buzzer and an LED, triggering them to turn ON.