Embed Size (px)
Citation preview
www.techvilla.org.in
1
TECHVILLA
www.techvilla.org.in
RF MODULES TX433 & RX433
www.techvilla.org.in
RF COMMUNICATION
RF Communication •Widely used, including Bluetooth,Radios,Cell phones, Satellite etc •Wide range, from few meters to millions of kilometers (Can be Used to control Robots in Mars) •Does not requires two devices to be in line of sight. •Can cross many obstacles •Circuits can be complicated and costly.
www.techvilla.org.in
RF MODULE
• A RF Module is a small circuit pre built and tested.
• They comes in Pair. One is RX or the receiver and other is a TX or Transmitter.
• Typical data rate is 1000 bits per seconds.
www.techvilla.org.in
PIN DESCRIPTION
TX 1. Antenna 2. Vcc (Positive Supply) 3. DATA (Data Input) 4. GN
RX Antenna
1.GND
2.GND
3.Vcc (Positive Supply)
4.Vcc (Positive Supply)
5.DATA
6.DATA
7.GND
www.techvilla.org.in
• Transmitter and receiver modules are tuned to work correctly at 433.92MHz.
• Transmitter can be powered from 3 to 12V power supply while receiver accepts 5V.
• 5V is common for AVR microcontrollers so no problems with interfacing.
• Modules don't require addition components
• For better distances apply 30 – 35cm antennas.
• Modules use Amplitude-Shift Keying(ASK) modulation method and uses 1MHz bandwidth.
www.techvilla.org.in
Atmega16 connection with TX
www.techvilla.org.in
Atmega16 connection with RX
www.techvilla.org.in
working
www.techvilla.org.in
HT12D & HT12E
www.techvilla.org.in
Encoder circuit using HT12E
www.techvilla.org.in
HT12E
• The HT12E is an encoder.
• It converts digital signals into suitable form to be transmitted through EM signals.
• It is an 8-bit Encoder.
• The HT12E is usually used for 433 MHz wireless modules.
• It is an 18 leg IC.
www.techvilla.org.in
PIN description
• A0: 7 – these are the address pins.• GND – this is the ground pin. This pin should also be connected to the –ve of the battery.
• Vcc – the VCC pin is where we need to supply the input voltage for the working of the encoder. It is used to power the IC.
• Osc1: 2 – these pins are the oscillator input and output pins. For the ordinary circuit, they are connected to each other with the help of an external resistor.
• TE – this is the transmission enable pin. When this is given true, then data transmission start.
• Output – this is an output pin. The data in EM signals is given out from this pin.• AD0: 3 – these are the data/address pins.
www.techvilla.org.in
HT12D Decoder
• The HT12D is a decoder.
• It decodes signals into suitable form to be transmitted through EM signals.
• It is an 8-bit Encoder.
• The HT12D is usually used for 433 MHz wireless modules.
• It is an 18 leg IC.
www.techvilla.org.in
PIN configuration
• A0: 7 – these are the address pins.
• Vss – this is the ground pin. This pin should be connected to the –ve of the battery.
• VDD – the VCC pin is where we need to supply the input voltage for the working of the encoder. It is used to power the IC.
• Osc1: 2 – these pins are the oscillator input and output pins. For the ordinary circuit, they are connected to each other with the help of an external resistor.
• DIN – this is the Data input pin. The data input from the receiver module is fed in this pin.• VT – this is an output pin. This pin gives the output as soon as any signal s received by the receiver.
• D8: 11 – these are the data pins.
www.techvilla.org.in
THE TRANSMITTER CIRCUIT
1.The Ground pin needs to be grounded. 2.The Vcc pin needs to be given regulated 5 Volts.
3.The output pin is connected to the data pin of the Tx module. 4.To enable transmission, the TE pin is grounded. 5.Resistors of 1.1MΩ are connected across Osc1 and Osc2 pins. 6.Pull-up resistors of 100KΩ are connected across D8, D9, D10, D11 pins. 7.The other end of the resistors may be either grounded, or given 1, or 8.left floating depending upon what we want as the default value from the output pins of HT12D. 9.Suppose we ground the resistors’ other ends, then, by default, all the output pins in the HT12D will receive 0, and similarly vice-versa. 10.Switches may be used in between the data pins and the resistors.
www.techvilla.org.in
THE RECEIVER CIRCUIT
• The address pins must be given the same configuration as of those given in the transmitter circuit.
• The VSS pin is to be grounded. Similarly, a 5v regulated output should be given to the VDD pin.
• The D8, D9, D10, D11 are the outputs corresponding to those in the transmitter circuit.
• A resistance of 51KΩ should be applied across Osc1 and Osc2 pins.
• The data output from the receiver module is to be connected to the DIN pin.
• The VD pin gets ‘on’ whenever the receiver receives a signal. It may be left unconnected.
www.techvilla.org.in
Diagram
