Technology

Continued exponential growth in the worlds population has heightened the stress on most of the resources the society needs to live. Energy is one of such resources and the world is struggling to meet its energy requirements. In lieu of these circumstances, there is an urgent need to conserve energy. It is the responsibility of us in the technology field to come up with solutions tailored to help the society to conserve energy by using it sparingly and only when needed. The DaySwitch is an example of how technology can be used to save energy in homes, offices and industries. It is a simple device, which uses microprocessor logic to turn lights on or off depending on a rooms ambient lighting (Allan).

There have been switches that reduce light emission in filament and halogen lamps but they are not applicable in fluorescent lamps and bearing in mind that the use of fluorescent lamps is increasing due to their low power consumption, there was a need to engineer light controllers that can automatically control these lamps (Allan). This is the motivation behind the invention of the DaySwitch. This device is capable of reducing the use of energy in lighting efficiently in commercial buildings and homes without the drawbacks exhibited by dimming systems (Rensselaer Polytechnic Institute). Dimming systems are hard to program and install and are expensive.

The DaySwitch consists of two essential components an optical sensor and a microcontroller unit (Allan). External circuitry is connected from the microcontroller unit to the lighting system of the building in which lighting is to be controlled (Rensselaer Polytechnic Institute). An optical sensor is a transducer that converts light energy into an electric current (Rensselaer Polytechnic Institute). It is this electric current that is applied to the microcontroller as an input to trigger an action that is either to turn on the lights or to turn them off. Externally, it is connected to a solenoid switch that turns the lighting systems power supply on or off depending on the signal produced by the microcontroller (Allan).

The microcontroller is a very minute electronic component that has inbuilt logic elements capable of processing a signal or a combination of signals to produce an output signal that can be used to control an external system through actuators (Allan). It is mainly built using digital electronic devices and therefore uses a very little amount of electric power. Since digital circuits run on direct current averaging 12 volts, a microcontroller has an in-built power inverter that converts nominal supply-line voltages, normally 240 volts alternating current, into the desired maximum of 5 volts (Allan).

Now, let me explain how the DaySwitch works. The optic sensor is strategically placed in a position where the natural lighting is optimum (Rensselaer Polytechnic Institute). It then generates an electric current whose magnitude is dependent on the amount of light falling on it. If natural ambient lighting is insufficient, it will generate an insignificant potential difference (Rensselaer Polytechnic Institute). This zero voltage (the sensors output while it is not generating any voltage) is fed into the microcontroller. The logic of the microcontroller is programmed in such a way that when it receives a zero voltage from the sensor, it turns on a secondary circuit, called the controlled circuit. This is achieved by the use of a NOT gate (Rensselaer Polytechnic Institute). A NOT gate is a digital integrated circuit, which takes an input and inverts it that is if it receives a False (logic level 0) at its input, it generates a True (logic level 1) at its output (Rensselaer Polytechnic Institute). False and true are terms defined in digital electronic technology to represent voltage levels a false level represents voltages ranging between 0 and 2.8 volts while a true level is from 3 to 5 volts. At logic level 0, the microcontroller, through inversion, turns on a secondary circuit, which feeds a live signal into an amplifier. It is this amplified signal which, through a solenoid, turns on a mechanical switch coupled to the buildings lighting power supply to turn on the lights (Rensselaer Polytechnic Institute).

When natural lighting is sufficient enough, the optical transducer generates voltage to create a logic level 1 at the microcontroller inputs (Rensselaer Polytechnic Institute). The inversion circuit is then turned off, supplying no electric current to the amplifier. The amplifier in turn feeds a zero current to the solenoid operating the electromechanical switch, which goes and opens the circuit supplying electricity to the building (Rensselaer Polytechnic Institute). The lights then are automatically turned off. The DaySwitch operates continually switching lights off during brighter times of the day when natural light is sufficient on its own and turns lights on when darkness begins to creep in (Science Daily).

A DaySwitch works with all types of electric lamps. It uses very simple circuitry, is cheap and is relatively easy to install (Science Daily). Since it applies the principles of digital electronics, it accurately determines light intensity and reliably turns lights on and off when necessary. I would therefore recommend its usage in homes and offices as it is a technology that has the potential to reduce the consumption of electricity and minimize power demand on the national grid.