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As home automation continues to increase in demand, System X offers another type of technology to benefit consumers. The main objective of this project is to design and build an electrical outlet that is able to be controlled remotely from a computer. Ideally, this design is focused on in-home use, but can also be installed in many other types of buildings as well. |
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Although the electrical outlets will appear as astandard GFIC outlet, the circuitry within the outlet is replaced with components needed to satisfy the project objectives. The changes and additions necessary for this project include an LED, an on/off/reset push button, a 48V to 5V DC switching regulator, a solid state relay, a current sensor, communication circuitry, and a microcontroller.
The LED is used to display the state of the outlet. When the LED light is on or off, the outlet will be on or off, respectively. If the LED is blinking on and off, that means the outlet is in overload and needs to be reset from the pushbutton. By holding in the pushbutton for two seconds, the user can toggle the outlet on/off, or reset the outlet to get it out of the overload state. The 48V to 5V DC switching regulator is used to power the circuit within the outlets. The solid state relay is the component on the circuit that able to turn the outlet on or off. The current sensor is needed to prevent danger to the user. This component observes how much current is being drawn through the outlet. When the outlet reaches the threshold value of 8 amps, the solid state relay shuts off and the outlet is put into overload state. The state of the outlet is sent to a computer for the user to view. Communication circuitry is needed because the computer can not directly communication to the microcontroller to carry out commands, and vice-versa. The microcontroller controls all functionality of the outlet. This component communicates to the computer to implement various commands. In addition to communicating with the PC, it also controls the solid state relay, LED, pushbutton functions, and reads the current values from the sensor |
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The control box is an interface between the computer and the outlets, receiving a serial (RS-232) signal from the computer transmitting it to the outlets via CAT5 cable using the RS-485 standard. The series connection of a MAX232 communication chip with a MAX489 communication chip will take care of the translation from the RS-232 standard to the RS-485 standard. The MAX232 chip will also connect to the CAT5 cable and the PC, but this CAT5 cable will terminate with an adapter which will allow it to connect to a PC's COM port. In addition to mediating communication between the outlets and the PC, the control box will power all of System X's hardware. A prefabricated 48V DC power supply will provide the necessary power, which will be transmitted via CAT5 cable. A MAX5033 voltage regulator will also reside within the control box, in order to power the MAX232 and MAX489 chips inside the control box. |
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| The computer program is how the user will communicate his/her commands to each of the outlets. The program will include ON/OFF, Lock, Affect All, Update Status, Timers, and Profile functions. After initializing each outlet, the user will have complete control over the status of the outlets. This program was created using Visual Basic.Net and is user-friendly, containing various error notifications. |
Sponsored By: PSU Entrepreneurship Program
Instructor: Timothy Wheeler
Any Questions or Comments? Please contact us at PSUSystemX@gmail.com