These two ICs together form an Encoder and Decoder pair. So out of the bits 8-bits will be used to set address and the remaining 4-bit will be used to transmit data. So if you are working on a project which has to transmit a 4-bit data from one end to other either by wire or wireless then this IC pair will be best suited for you. The IC is has a wide range of operating voltage from 2. Pull the Transmission Enable pin pin 14 to ground to activate transmission. For decoding a data the IC will requires an oscillator, luckily this IC has one in-built.
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Transmission enable pin allows the data to transmit from data input to data output pins. It only acts as a switch which allows controlling the transmission of data with the use of external devices.
OSC2 Pin 15 — Pin 15 is an oscillator output pin of the encoder. An external oscillator is usable at the OSC2 pin. OSC1 Pin 16 — Pin 16 is an oscillator input pin of the encoder.
OSC1 pin will use with the external oscillator input or the second terminal of the 1M resistor. VDD Pin 18 — Pin 18 is a power input pin of the encoder. Voltages on this pin will make the IC functional. CMOS technology makes the encoder a low noise immunity device. RF and IR modules can use directly with encoders. The encoder can convert 4-bit data to serial data. The encoder uses 0. Only different combinations of addresses are usable with HT12E HT12E Encoder Applications In remote control systems, this encoder is widely available for encoding the data for transmission.
Recently IoT production has been increased very much. Most of the smart systems communicate with each other wirelessly which also has HT12E to avoid the load on the internet. Smoke and builder alarm system encoder their message by HT12E. HT12E Encode Working The primary function of the encoder is to encode the bit parallel input data and then forward it towards the output pin.
In these bits, 8 of them will come from the address pins and the rest of them will be from data input pins. The address pins are eight in numbers which describe the address of encoded signal. Most of the devices attached to the encoder only broadcast the signal. The broadcasted signal has an address that gets identified by the decoder to receive the data.
The address is like a security for the communication system. In those cases where two receiving end or sending ends have the same address, then devices start messing with each other. Data Pins The next part is the data pins. These pins are 4 in number and these four pins describe the data in the encoded signal.
The encoded signal gets the address and data in the form of logic states mostly. Due to the availability of microcontrollers and other smart devices the input signal can be applied through their GPIO pins. To use the encoder with external devices always check for their voltages otherwise the encoder can be destroyed. Most of the time the control pin remains active but in special security cases, this can be controlled.
The encoder signal always encodes with the oscillator speed. The output data of the encoder will be in serial form. This serial data can be sent through a wire or by any third device like IR of RF etc. You may notice that there are multiple buttons on the remote and each of them delivers a different function. Each button of the remote sends the different data input on the encoder and then the encoder passes it to the output pin.
These addresses make them operate with their desired devices. Here the IR transmitter circuit with encoder but the same circuit can be generated for RF just by replacing the IR transmitter. Interfacing Example with Arduino In addition to the above example circuit, You can also see this example on IR transmitter and receiver interfacing with Arduino.
This address can only be from combinations of 8-bits. This makes the device limited. In most of the cases, the generated signal has a theft issue. Because the signal is broadcasted and unable to trace the receive. The address of the signal can be guessed by any receiver. This address limitation makes the use of the HT12E suitable only at a shorter distance. At a shorter distance, the send and receiver can view each other, like the TV remote, Home Security, etc.
In most of the cases, the address pins use the same logic state and work and avoid to take a complex address as an input. You may notice in commercial products, some remote control cars can be operated with a single remote at a time. Because they are designed for shorter distance and the company to avoid the complex address input and given the same address to all the devices.
HT12E RF Encoder IC for wireless communication