PC Based Four Channel Home Automation Controller Controls up to 4 Channels with different Equipment No. This project controls ON and OFF of four appliances by simply giving the Equipment No. through program written in C language. The program accepts the input in decimal nos. from 1 to 4 through keyboard and outputs at the data output pins of the PC’s parallel port as shown in the circuit diagram. The interfacing circuit comprises four opt couplers and latching circuit.
About the Circuit :
Figure shows the circuit for interfacing the PC’s parallel port to the devices to be controlled. The parallel port outputs the control signals generated by the software. The control signals are not continuous but a signal clock pulse. For every ‘ON’ or ‘OFF’ control, only a single clock pulse is sent from the parallel port to the circuit. Port 2 to 5 are connected to pin1 of opt couplers IC. Opt couplers ensure complete isolation of the parallel port’s from the load drive circuit using TRIAC. When a high going pulse is available on the port, opt coupler provides a clock pulse to the corresponding flip-flop IC section. IC5 and IC6 is a dual flip-flop with independent set, clear and clock inputs and single output. It accepts data when its clock pin is low and transfers it to the output on the positive-going edge of the clock. The high Q output of the flip-flop drives the corresponding transistor to energize the relay and switch ON/OFF the device. The flip-flops are set up for toggle mode by connecting their D inputs to `Q outputs. Set inputs of all the flip-flops are grounded. Switch S1 is used to reset the flip-flops manually.  Before attempting to control the devices the program is to be run. When program is run, it asks for enter the equipment number, which should be ON. After entering the device number from 1 to 4, the control pulse available on the corresponding port and toggle flip-flop switches from ‘OFF’ state to ‘ON’ state to trigger TRIAC and load is ON. LEDs are also given to indicate the status of device. Similarly, to turn the device ‘OFF’, press the device number on the keyboard. This again makes a high control pulse available on the port and the corresponding toggle flip-flop switches from ‘ON’ state to ‘OFF’ state and the device is OFF. The program can be terminated simply by pressing the ‘E’ key, but before that you should turn all the devices OFF. If you try to terminate the program without shutting down any of the device, the message, “Please shutdown all the equipment” will appear on the screen for a short time.

PC Based Four Channel Home Automation Controller Controls up to 4 Channels with different Equipment No. This project controls ON and OFF of four appliances by simply giving the Equipment No. through program written in C language. The program accepts the input in decimal nos. from 1 to 4 through keyboard and outputs at the data output pins of the PC’s parallel port as shown in the circuit diagram. The interfacing circuit comprises four opt couplers and latching circuit.
About the Circuit :
Figure shows the circuit for interfacing the PC’s parallel port to the devices to be controlled. The parallel port outputs the control signals generated by the software. The control signals are not continuous but a signal clock pulse. For every ‘ON’ or ‘OFF’ control, only a single clock pulse is sent from the parallel port to the circuit. Port 2 to 5 are connected to pin1 of opt couplers IC. Opt couplers ensure complete isolation of the parallel port’s from the load drive circuit using TRIAC. When a high going pulse is available on the port, opt coupler provides a clock pulse to the corresponding flip-flop IC section. IC5 and IC6 is a dual flip-flop with independent set, clear and clock inputs and single output. It accepts data when its clock pin is low and transfers it to the output on the positive-going edge of the clock. The high Q output of the flip-flop drives the corresponding transistor to energize the relay and switch ON/OFF the device. The flip-flops are set up for toggle mode by connecting their D inputs to `Q outputs. Set inputs of all the flip-flops are grounded. Switch S1 is used to reset the flip-flops manually.  Before attempting to control the devices the program is to be run. When program is run, it asks for enter the equipment number, which should be ON. After entering the device number from 1 to 4, the control pulse available on the corresponding port and toggle flip-flop switches from ‘OFF’ state to ‘ON’ state to trigger TRIAC and load is ON. LEDs are also given to indicate the status of device. Similarly, to turn the device ‘OFF’, press the device number on the keyboard. This again makes a high control pulse available on the port and the corresponding toggle flip-flop switches from ‘ON’ state to ‘OFF’ state and the device is OFF. The program can be terminated simply by pressing the ‘E’ key, but before that you should turn all the devices OFF. If you try to terminate the program without shutting down any of the device, the message, “Please shutdown all the equipment” will appear on the screen for a short time.