Subject : Microcontroller and Embedded Programming

Topic : Embedded System-The Case Studies

Difficulty : Medium

Automated meter reading (AMR) system:

● The automated meter reading system can be used to read the power consumed and hence generate the power bill.

● An example of such a system is shown in fig 12.2

● The various components that will be required are shown in the fig(a) are: power supply, clock or oscillator circuit, communication port like LCD display, current and voltage sensors along with the ADC, modem, wireless AMR interface, memory for program and data and the microcontroller.

● The power supply is implemented using a transformer, followed by rectifier and finally a regulator.

● The clock circuit is implemented using the standard circuit prescribed by Intel for 8051. The crystal circuit of 11.059MHz is used so that the serial communication can be implemented easily.

● The interfacing of the 16x2 LCD is done. The various signals connected of the LCD display are power supply pins, the Vee pin, data pins, RS, RW, and E.

● The current sensor will be used to measure the current and the voltage sensor to measure the voltage. The product of these will give the power consumed. The voltage and current measured will be analog values that will have to be converted to digital values. This will be done ADC.

● The communication is implemented in a special manner using the wireless AMR interface. This will be an RF(Radio Frequency) module to communicate with the system. An external RF reader or receiver can be used to get the information from the system about the power consumption.

● The modem used is also a special one. It implements a wired communication from the system to the office of the power provider. The wire used for this is the power line itself. A special mechanism can be implemented to transfer the data over the power line and being received over the other end in the office of power provider.