rf controlled home application
Used to make a wireless remote control that can be used to drive the output from a distance.
As the name suggests, the RF module sends signals using radio frequency.
These signals are transmitted at a specific frequency and baud rate.
The receiver can receive these signals only if the receiver is configured for this frequency.
The system also uses a four-channel encoder/decoder pair.
On the transmitter side, the input signal is received through four switches, while the output is monitored on a set of four LEDs corresponding to each input switch.
The circuit can be used in the design of remote electrical control system.
The output of the receiver can drive the corresponding relay connected to any household appliance. RESISTORS 1)39K--12)180K--13)560 OHMS--14)1 K--15)730K--1CAPACITORS1)100MFD /16V--12)100UF--1TRANSISTORS1)BC558---12)SL100---1SWITCHES8-
Pin DIP switch or ON-OFF SWITCHES--1RELAY 5V--1ON-OFF SWITCHES --1 RF module RX-434A, TX-434AIC\'SHT 12D---1HT 12E--1CD4017 4B--17805--
1 wireless remote control using RX-based SNAP9V BATTERIESPCB RFTX MODULES (434MHz. )
This radio frequency (RF)
Amplitude Shift Keying is used in the transmission system (ASK)
With transmitter/receiver (Tx/Rx)
A pair working at 434 MHz.
The transmitting module uses serial input to transmit these signals through RF.
The signal sent is received by the receiver module placed far away from the sending source.
The system allows one-way communication between two nodes, that is, transmission and reception.
The RF module is used with a set of four-channel encoder/decoder ICs.
HT12E and HT12D are used as encoders and decoders respectively.
The encoder will input in parallel (
From remote switch)
Serial collection of signals.
These signals are transmitted continuously through RF to the receiving point.
The decoder is used to decode the serial format after the RF receiver and retrieve the original signal as the output.
These outputs can be observed on the corresponding led. Encoder IC (HT12E)
Receive parallel data in the form of address bits and control bits.
The control signal from the remote switch and the 8 address bits form a set of 12 parallel signals.
The encoder HT12E encode these parallel signals into serial bits.
Enable transmission by providing ground to the active low level pin14.
Control signal at Pin 10-13 of HT12E.
When receiving serial data from the encoder IC, the serial data is fed back to the RF transmitter via the pin17 of the ht12e transmitter (HT12E)
Wireless transmission to RF receiver.
After receiving these signals, the receiver sends them to the decoder IC (HT12D)through pin2.
Receive serial data on the data pin (DIN, pin14)of HT12D.
The decoder then retrieves the original parallel format from the received serial data.
When the data pin of HT12D does not receive the signal, it is still in standby mode and consumes very little current (less than 1μA)
Voltage for 5 v.
When the receiver receives the signal, it is given the DIN pin (pin14)of HT12D.
The HT12D oscillator is activated when the signal is received.
IC HT12D then decodes the serial data and checks the address bits three times.
If these bits match the local address pin (pins 1-8)
It then places the data bit on its data pin (pins 10-13)
Make the VT pin high.
LED connected to the VT pin (pin17)of the decoder.
This LED is used as an indicator indicating the effective transmission.
Therefore, the corresponding output is generated on the data pin of the decoder IC.
10-send signal by lowering any or all pins
Receive 13 of HT12E and corresponding signals on the receiver side (at HT12D).
The address bit is configured by using the first 8 pins of the encoder and decoder ic.
To send a specific signal, the address bits of the encoder and decoder ic must be the same.
By properly configuring the address bit, a single RF transmitter can also be used to control different RF receivers of the same frequency.
All in all, in each transmission, 12-bit data is transmitted by 8 address bits and 4 data bits.
Receive the signal at the receiving end, and then send the signal to the decoder IC.
If the address bit matches, the decoder converts it to parallel data, and the corresponding data bit is reduced and then used to drive the LEDs.
The output of the system can be used for negative logic or not for doors (like 74LS04)
Can be merged at the data pin. The TWS-434 and RWS-
The 434 is very small and very good for applications that require the shortrangeRF remote control.
The transmitter module is only 1/3 of the size of the standard stamp and can be easily placed in a small plastic case. TWS-
434: the transmitter outputs up to 8 mW at 433.
92 MHz with a range of about 400 feet (open area)outdoors.
Indoors, the range is about 200 feet metres and will pass through most of the walls. . . . . The TWS-
The 434 transmitter accepts digital input and can be accessed from 1. 5 to 12 Volts-
DC, making the building a miniature hand
It is very easy to keep the RF transmitter. The TWS-
434 is about the size of the standard postage --
434: The receiver is also running at 433.
92 MHz with 3uV sensitivity. The RWS-
434 receiver from 4. 5 to 5. 5 volts-
Note: The recommended antenna should be about 35 cm long for the maximum range.
Conversion from CM to inches-multiply by 0. 3937.
For 35 cm, the length in inches is about 35 cm x 0. 3937 = 13.
7795 inch long
We tested these modules using a hobby wire of 14 \", solid, 24 specifications and reached a range of more than 400 feet.