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PROJECT BASICS
POWER SUPPLY
RELAY
CURRENT BUFFER
BIDIRECTIONAL CURRENT BUFFER
PARALLEL PORT
LEVEL SHIFTER
WIRELESS COMMUNICATION
TX433 & RX 433
ENCODER (HT12E)
DECODER (HT12D)
Calculating the value of RESISTANCE
PROJECT IDEAS
 

 

 

DECODER IC HT12D:

This is a 16 pin IC with the following pin diagram:

 

Pins 1-8 are the address bits. This 8bit address is sent along with the data and the data is accepted only at the receiver where address is same as the address of encoder. Hence we must make sure that both encoder and decoder have the same address.

Pin 9 is the Ground

Pin 10-13 are the data pins from where we receive DATA but only after it is made sure that data received is ERROR free.

Pin 14 is the DATA IN pin which is connected to the DATA pin of receiver RX.

Pin 15-16 we need to connect a resistance between these pins and the value of resistance is dependant upon the voltage applied and the frequency of transmission which is described later on.

Pin 17 is VALID TRANSMISSION pin. The data received is put at the output DATA pins only when data is found error free and only then this VT pin is made HIGH i.e. a HIGH at the VT pin indicates that DATA intended to be transmitted is received properly.

Pin 18 is the pin where we need to supply the voltage V.

 

And working can be understood from the following FLOW CHART:

We can see data is received 4 times after matching the address bits and then the DATA received is matched each of the 4 times before enabling VT pin.

 

 

 

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