DESIGN AND CONSTRUCTION OF MICROCONTROLLER TIMER SOCKET OUTLET
1.1 BACKGROUND INFORMATION
As the world becomes concerned with conserving electric power and the fuels that generate electricity, there is a growing need for the conscientious homeowner to keep an eye on and minimize their power usage.
Vampire or standby power is loosely defined as the “electrical power consumed by appliances while they are switched off (but are designed to draw some power) or in a standby mode. This only occurs because some devices claimed to be “switched off” on the electronic surface, but are in a different state from switching off at the plug, or disconnecting from the power point”. Switching off at the power point is effective enough to control the vampire power, there is no need to disconnect all the devices from the power point .
Some devices utilize vampire power in a useful manner to provide persistence features such as maintaining clock settings between active sessions, convenience features such as powering the necessary hardware to respond to remote controls, and to eliminate long initialization times by keeping the hardware in a semi-powered state. Other devices have no beneficial use of vampire power, such as a powered but disconnected mobile device charger or an uninterruptible power supply (UPS) with no active system connected.
With advancement of technology, things are becoming simpler and easier for us. Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services .
The case of the MICROCONTROLLER TIMER SOCKET OUTLET helps in conserving the
vampire power. Electrical and electronic appliances are connected to the socket outlet and
programmed to be in power for a specific duration based on the user’s discretion. This goes a long
way in conserving energy as the device(s) is/are disconnected after the specified duration. It is very
useful in cases whereby the user has to keep in touch of what he or she had connected earlier and
due to the multitasking nature of human beings, we tend to forget what had been connected to
attend to other things in the household or wherever we find ourselves.
1.2 AIM AND OBJECTIVES OF THE PROJECT
The aim of this project is to;
Design and construct an automatic socket outlet with an operational timer incorporated into it using
The objectives of this project are as follows:
1. To conserve electrical power domestically.
2. To reduce and subsequently prevent electrical hazards in the home front.
3. To control the use of electrical power domestically.
4. Through conservation and control of electrical power, electricity bills are reduced.
1.3 PROJECT MOTIVATION
Since the advent of socket outlet manufacturing in developing countries like Nigeria, solution has
been found for power conservation or regulation. There is yet to be an effective socket outlet for
timing domestic socket outlets. The failure to have an operational timer for the socket outlets has
caused a lot of electrical hazards. This has claimed lives and properties of many people. The user often forgets to look after what he/she had connected and due to incessant power outages, he/she often forgets to switch off appliances earlier connected to power when leaving his/her home or due to carelessness of the user. Due to this negligence, the connected appliances continue to build up, when power is restored, even after completing their purpose of connection and when it gets beyond control, it damages the appliances. Repeated occurrences of these hazards have led to the loss of valuable things worth millions of naira.
However, with the help of a timer socket outlet, an effective solution is provided to these problems. An effective control timer for the socket outlet makes it safer and easier to use and also helps to reduce hazard rate. The use of a microcontroller comes to play in this motivation. Every microcontroller has a timer unit inside. A timer is nothing more than a time counting device fabricated inside the microcontroller unit. A wide range of practical applications require a timer in action. For example, we need to turn a motor ON for 5 minutes and then turn it OFF, how will we do that? A timer inside a microcontroller unit aids us in implementing this perfectly.
The circuit employs the use of various electrical and electronic components like resistors, capacitors, light emitting diode (LED), switches, piezoelectric buzzer, 13-amp socket outlet, jumper wires, 7-segment display, battery, relay, Vero board and most importantly, the Peripheral Interface Microcontroller 16F877 microcontroller (PIC 16F877).
The microcontroller is programmed using the “MikroC” software. It is programmed in such a way to communicate with all the other components on the board.
The switches are used to input instructions into the microcontroller. The instructions are basically the SET TIME, START, RESET and STOP.
The SET TIME instructions are displayed on the 7-segment display.
The START button signifies the beginning of the entire timing process.
If a wrong time is set in, the RESET button helps to restore it to default.
The STOP button helps to stop the timing process, this is necessary as there could be a change of mind after the process has started.
The battery serves as a temporary memory holder. If during the process, there is power outage and the set instruction has not been reached, it will help the circuit start from where it stops when power is restored. For example, a 12,000-litre reservoir fills to the brim in 30minutes, the set instruction will be 30minutes and if there is power outage after the 23rd minute, the battery helps to continue from where it stopped (23rd minute) to the 30th minute. However, a major limitation to this is in the use of a boiling ring, or for the purpose of boiling. If experimentally, pure water boils in exactly 10mins, and power outage occurs in the 7th minute for as long as 30minutes, when power is restored, the water cannot boil in 3minutes again. So this is where the STOP button comes to play.
The buzzer and the LED serve as audio and visual indicators respectively. They indicate the completion of the timing process. They indicate that the process was completed according to the set instruction. After completion, the circuit automatically shuts the relay off which stops the supply of power to the circuit thereby conserving power.
The 13-amp socket is used for appliances with fuses rated 13A and below, examples are phone chargers, television, etc.
The microcontroller, capacitors, transformer, relay, etc. serve different purposes which will be discussed in subsequent chapters.