By Ebele Orakpo

The need to improve security and power supply cannot be over-emphasised. Realising that this task should not be left to government alone, that all hands must be on deck, some science students of New Total Child Academy, Yenagoa, Bayelsa State, decided to contribute their quota by putting into practice what they had learnt.

In this chat with Vanguard Learning at the University of Lagos during the 9th edition of the annual Nigerian Secondary Schools Science Fair and Quiz Competition organised by Genius Illumina, they spoke on their latest innovations. Excerpts

Reason for the project:
According to the students, the security system powered by an alternating current (AC) inverter, is multipurpose because it detects fire as well as burglary. The students said they embarked on the project when they observed that most enterprises do not survive due to power problem and insecurity, so they came up with a durable, noise-free and affordable inverter. The device consists of potentiometer (for measuring the potential (voltage) in a circuit), light-dependent resistor for burglary, transformer, battery, buzzer, cell phone, switch, LM331, 555 timer fitted to the sound system, etc.

*From left: Ado Isaac Epamowei, Justin Tobi Chimora and Bio-Ibogomo Ebikienmo.

Mode of operation:
Explaining how the device works, Bio-Ibogomo Ebikienmo said; “Once you are not in your environment, you turn off the sound and immediately a thief walks into your house, the system sends an sms to you, alerting you that there is someone in your house without alerting the criminal. You can then call the security operatives to catch him/her red-handed. You know with the sound turned on, the criminal will be aware that something is wrong when the system begins to beep and will run for his dear life.

“Also, any slight change in temperature immediately triggers the device and it starts beeping and once it starts beeping and alerting the environment, it immediately sends message to anybody whose phone number is stored in the cell phone connected to the device thereby alerting them that there is a problem in their environment.”

Continuing he said; “The power generated by the inverter is 220 volts ac which can be used to power a home, shop or factory. Once the power is generated to the device, it has a step-down transformer which steps down the 220 volts to 9 volts ac, then it moves through a grid rectifier which converts the ac to direct current (dc). Subsequently, the 9 volts is further split into 4.5 volts each, so the device just uses 4.5 volts to power itself.

*The device, SMS-based multiputpose security system

“For the sound section, we installed a 555 timer. Each 555 timer gives the device the beeping sound/the danger alert. Without the timer, it will just be a plain noise like the motor horn.

The phone is connected to an electromagnetic relay which enables the it to send messages automatically. If someone goes into your house or if the environment is unsafe, the device alerts you, letting you know that something is wrong. With this, your environment is safe,” he said.

Using Faraday’s law of electromagnetic induction, the students were able to create an ac inverter.

The law states that The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux through the circuit. “We brought this into play as can be seen in the step-up transformer. We have the primary, secondary and magnetic coils. So once you introduce an alternating current to the primary coils, your electromotive force (emf) reduces in the secondary coils, which means the voltage in the secondary coils will be greater than that at the primary coils so this is what we use to generate power,” said Justin Tobi Chimora.

Contributing, Ado Isaac Epamowei said; “To keep the system running for 24 hours, we made it multi-powered. First, it can be powered by inverter, the grid (PHCN), generator and also solar panel but in the absence of all these sources of power, we installed a battery inside to keep it running continuously without you coming to change anything. In the absence of the inverter, it will still work without being connected to any source.”

Appeal to govt and organisations:
The students appealed to government and the private sector for funds to enable them produce the device commercially. “You can save the money you pay security guards every month by using just a part of it to buy this device,” they said.