DESIGN AND IMPLEMENTATION OF THE ELECTRONIC MOSQUITO REPELLENT CIRCUIT USING 555 ASTABLE MULTI-VIBRATOR CIRCUIT

ABSTRACT Control of mosquitoes is something of utmost importance in the present day with rising number of mosquito borne illnesses. The effect of mosquito bites cannot be overlooked considering how many deaths it has caused over the years. Specialty products like mosquito repellent used to combat mosquitoes are required but most of the repellants available use chemical means to repel or kill the mosquitoes which in a long run also becomes detrimental to ourselves and the environment. This project presents the design and testing of an electronic mosquito repellent. The project aims at developing a device that is capable of emitting ultrasonic energy of varied frequencies. These frequencies do affect the auditory senses of pests such as mosquitoes, rodents, avian and nocturnal insects by making them uncomfortable in their abode. However, these frequencies do not affect the hearing ability of humans. This electronic mosquito repellent is based on the 555 timer IC. This is a simple and useful mosquito repellent. The mosquito repellent circuit generates an ultrasonic sound with a high output frequency that spreads within a wide radius. The circuit is quite simple and require few external components. The oscillation frequency is given by the value of resistors and capacitors and can be modified by changing the value of the capacitors or replacing the fixed resistors with a variable resistor (potentiometer). The actual oscillation frequency of this electronic mosquito repellent is above 20 kHz so what is needed is a good high frequency piezo speaker. The electronic mosquito repellent circuit can be supplied from a 12 V DC power supply. The method is to generate a high ultrasonic sound output capable of repelling mosquitoes within a wide range with minimum electronic components. In order to achieve this, the 555 timer is connected. The 555 timer has the ability to convert an analog signal input (voltage) to digital signal output (frequency). The result is that the 555 timer can produce or generate frequencies between 20 and 60kHz. This frequency can repel female mosquitoes and does not pose any threat health x since frequencies above 20kHz cannot be heard by humans. The results of the various tests carried out (test conducted in the opening that conducted in the classroom, those conducted during the day and finally those conducted in the night) showed that the device had effect on mosquito landing rate and actually caused repulsion. However, the project is yet to reach full completion since it can be improved upon. The circuit can be improved upon in the following ways: i. Sensor and LED light can be connected in the circuit to detect the presence of mosquitoes. The implication of this is that if the LED light does not function (light), it will indicate an area free mosquitoes.