One Damaged Mosquito Swatter was in my home with full of dust. So, decided to salvage its parts to reuse for other purposes. Just to avoid e –waste and to do some kind of Recycling. Well, it has a good 2.4V Rechargeable Battery and a circuit board. The problem is in its circuit board that generates high volt AC to burn the Mosquito. But the charger is still working. So decided to use the charger part to make a High power Rechargeable LED Flash light. The Mosquito Swatter generates a high voltage between 400- 1000 volts from the 2.4 V battery. For this, there is an oscillator circuit and an Inverter transformer. The Inverter transformer converts the 2.4 V DC from the battery to around 200V AC. The oscillator circuit makes the AC waveform. The 200 V AC thus produced is then boosted by a Voltage Multiplier comprising some high volt capacitors and diodes. This boosted AC appears in a High volt Capacitor which then passes it to the Nets of the Swatter. The middle net of the Swatter is Positive while the outside nets are Negative. When we press the switch, the High volt capacitor discharges high volt AC to the nets. When the Mosquito passes through the net, it explodes due to high voltage. Even though the AC voltage is very high around 1KV, Current is negligible. Let us see how that Swatter turned into a Rechargeable Flash light.
Unscrewed the handle of Swatter. The electronics is inside. First detached the wires going from the PCB to the nets. Then detached the Inverter transformer with Voltage Multiplier part from the PCB. Now the PCB has only the Charger circuit attached to the battery.
Tested by connecting AC. Charger is properly working and charging the battery. The charger circuit consists of an X rated capacitor, and IN 4007 diodes. The value of the capacitor erased by the maker, to avoid servicing once damaged. Clever people! But I found out its value. It is 1 uF 400V capacitor. So it gives sufficient voltage and current to charge the battery.
The Rechargeable battery in the Swatter is two Nickel Cadmium batteries rated 1.2V forming a pack of 2.4V. This voltage is not sufficient to light the 1 Watt White LED because it requires 3.6 – 4V. So it is necessary to change the battery. Decided to use a low cost 4V, 0.5 Ah rechargeable Lead Acid battery. It costs only Rs.30
Made some rewiring. Connected 1 watt White LED. Connected the switch between the Positive of LED and the Positive of battery. The negative of LED is connected to the Negative side of PCB. The AC connections to the PCB for charging are intact. The AC connections go to the PCB. See image
It is illuminating my Roof top Vegetable garden
Connected the Flash light to AC. Battery is charging well
Now what to do with the remaining three parts.
Battery can be used for other projects because it is a good Ni Cd pack that costs around Rs.100.
Then how to use that Net. It can be used to make a Metal Detector later to wind the copper wires around it.
The Inverter Transformer finds an application to make a Mini Inverter. The High voltage capacitors are useful to make some Lightning arresters.
So that complete Swatter can be used for other purposes to reduce e-waste.