The ht12e and ht12d are popular remote control encoder and decoder ICs from Holtek Semiconductor. These chips are commonly used in wireless remote control applications for their reliable transmission, low power consumption, and simple interfacing. In this in-depth article, we will look at the key features, specifications, and pricing information for both the ht12e encoder and ht12d decoder chips.
Overview of the ht12e Encoder
The Holtek ht12e is a 4-bit remote control encoder chip that takes parallel input data and encodes it for wireless transmission. Some key features of the ht12e include:
- Encodes 12-bit data
- Supports up to 16 channels with adjustable pins
- Low power consumption – less than 1mA at 1.8V
- Operating voltage range of 2.4V to 12V
- Data transfer rate up to 7.5kbps
- Transmission distance up to 200m
The ht12e uses Holtek’s PILOT transmission technology which helps prevent transmission errors and increase reliability. It can be paired with various types of modulation like ASK/OOK, FSK or PSK depending on the application requirements. Overall, it provides a versatile remote control encoding solution.
Overview of the ht12d Decoder
The ht12d is a 12-bit remote control decoder IC that works together with ht12e encoders. Its key features are:
- Decodes 12-bit serial input data
- Operates at voltages between 2.4V to 12V
- Low power operation – 0.6mA at 2.4V
- Data transfer rate up to 8kbps
- Sensitivity down to -105dBm
- 16 channel options with adjustable pins
This decoder chip receives encoded serial data, performs clock timing recovery and data extraction before outputting the decoded parallel data. It can pair with various wireless modulation techniques making it adaptable. The ht12d provides reliable decoding with transmission distances up to 200m.
The ht12e and ht12d chips are affordably priced, making them cost effective options for adding wireless control. Here are typical pricing details:
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Purchasing in larger quantities can reduce the per unit cost further. Both through-hole DIP and surface mount SOIC packages are available. Overall, these Holtek encoder and decoder pairs deliver excellent functionality and reliability at a budget-friendly price point.
Using the ht12e and ht12d ICs
Using the ht12e and ht12d encoder/decoder pair for wireless control is straightforward. Here is a typical application diagram:
The parallel input data is connected to the ht12e encoder IC. This data is encoded and modulated onto a carrier signal by the RF transmitter module. The transmitted RF signal is picked up by the receiver module and demodulated. The extracted serial data is sent to the ht12d to be decoded back into parallel output data.
To set up a basic wireless link, the carrier frequency, data rate and transmission power must be configured to match between the transmitter/receiver pair. The encoder and decoder ICs allow for multiple transmission channels via the ADDR pins. Common RF modules to pair with the ht12e/ht12d include:
- ASK/OOK transmitters and receivers at 434MHz
- FSK transmitters and receivers at 433MHz
With just a few additional passive components, short range wireless remote control can easily be implemented.
The Holtek ht12e and ht12d provide a versatile, low cost encoder/decoder solution for adding wireless control capabilities. Their reliable transmission, low power operation and simple interface make them ideal for remote control applications. With pricing starting at just over $1 each in quantities, they deliver outstanding value. Whether you need unidirectional or bidirectional wireless control, this encoder/decoder pair is a great choice.
Frequently Asked Questions
Q: What is the main difference between the ht12e and ht12d?
A: The ht12e is an encoder IC that takes parallel input data and encodes it for wireless transmission. The ht12d is a decoder IC that receives the wireless transmission and decodes it back into parallel output data. They work together as a pair.
Q: What modulation techniques can be used with the ht12e/ht12d?
A: They support various modulation types like ASK/OOK, FSK and PSK depending on the RF transceiver modules they are interfaced with. Common options are ASK and FSK operation at 433-434MHz.
Q: What is the maximum transmission distance possible?
A: The transmission distance can reach up to 200m or 650ft in ideal conditions. Factors like obstructions, RF noise and transmission power will affect the range.
Q: Can these chips be used for bidirectional communication?
A: Yes, they can be configured for bidirectional links by using two encoder/decoder pairs with separate transmit and receive modules. This allows remote control and telemetry data to be sent both ways.
Q: Are any special microcontrollers required to use the ht12e/ht12d?
A: No, they can interface to standard microcontrollers like Arduino, PIC, AVR, 8051, etc. No proprietary chips are required. Just general purpose I/O pins are needed.