Project halim Assignment Example | Topics and Well Written Essays - 1750 words

Project halim - Assignment Example The main function of the encoders and decoders is to convert parallel data to series data. Design of the control circuit The function of the control circuit will be to give an alarm to indicate the departure of the child. The communication process that will be employed is the RF communication because it is the most accepted and affordable cost solution. In the RF module, both transmitter and receiver pairs are essential because the communication uses the principle of serial communication. The module of operation demands a component that converts the n-bit data to serial data. The RF module can, therefore, employ Serial encoders or decoders (HT12D and HT12E) to convert the data or task. RF communication block diagram The block diagram of the RF communication illustrated above employs the encoders/decoders that are TTL compatible. Therefore, the input levels are depicted in a TTL Logic level. To solve the problem, the TTL input must be changed into serial data input. To have a serial d ata input, an encoder must be used because; it can be read directly by the RF transmitter performing the amplitude Key shifting (ASK) modulation, and further transmitting the data via antenna. At the receiving end, modulated signal by the antenna is received; the RF Receiver carries out the filtering, demodulation and processing of the transmitted data. The data obtained at the end is a serial data that is converted to a TLL level logic data. The RF Module The module comprises of an RF receiver and transmitter. The two operate at a frequency of 434MHz. The transmitter obtains serial data from the encoder and transmits it using a wireless platform provided by the antenna attached to the pin 4 (data). The transmission speeds are between 1Kbps and 10Kbps. The RF receiver operated at the same frequency as the transmitter to obtain the data transmitted. In most cases, the RF module is used beside coupled with a pair of encoder HT12E and Decoder HT12D. The encoder is useful in encoding pa rallel data for transmission while the receiver send the required signal to the decoder for decoding. Features Range frequency of the TX: 433MHz Supply voltage of the TX: 3V ~ 6V Coverage in open space (standard Conditions): 100 Meters Receiver Frequency (RX): 433 MHz Operating voltage of RX: 5V Supply current of the RX: 3.5 mA RX IF Frequency: 1MHz Low Power consumption Easy Application HT12E and HT12D The decoder (HT12D) is ICs comprising a series of CMOS for remote control applications. The IC is paired with an encoder HT12E with the HT12D main role is the conversion of the serial input to parallel output. The HT12D decodes the serial addresses and data that are received by the RF receiver, which in turn sends the parallel data to the output pins after processing. For successful operation, the paired decoder and encoder must have the same number of address and data format selected. The serial data and address from matching encoder, received by the decoder, is transmitted by a car rier employing the RF transmission medium providing output to the output pins. Consequently, the HT12E encoder IC is also a series of CMOS specifically for Remote Control applications. The purpose of its use is interfacing the RF. The suitability of the encoder is restricted to 12 bit information consisting of N data bits and address bits. The encoder converts the parallel input from the