Introduction: Lithium-Ion Charged Fly/Bug Swatter

About: General interest in DIY. Like to recycle electronics or adapt them for other use. Fan of bluetooth homebuild speakers. ICT interest.

Like every summer when it becomes hot and some doors and windows are left open, you get these unwanted guests ... flies, mosquitoes, etc... Nothing more anoying the these flies buzzing around your head and always seem to land on the uncovered parts of your body

Time to break out the electric swatter. I have to admit, these swatters bring me great joy when i manage to get a fly or mosquito on the high voltage surface and see the sparks....and puffs of smoke and little baking noises. Shame on you, admit it... You Like It Too!

Found at the exact location the wife told you to store it ( wife : if you put it always in the same location you'll find it back right away, husband: yeah yeah...) Then when you push the button of your joymachine.....nothing happens.

Opening the battery lid quickly reveals the same problem that occurs with battery operated guismos when you leave batteries in. A nice caked white mess around the terminals and battery. Damn...not again!

Last time that happend the wife dumped my joymachine so this time i saved it from getting decommissioned.

Recycle folks!

Okay, let's start at how to get this baby up and running on some better batteries that last and last...

Step 1: Things Needed

What you will be needing is :

°) An electric bug swatter.

)° A small size Philips screwdriver.

)° An exacto knife.

)° Soldering iron and solder

)° A 3mm drill bit

)° Strong glue

)° Pliers, i used a flat nose plier.

)° A Lithium Ion battery, like the 18650 model common found.

)° A Li-Ion charger pcb type TP4056 (5V - 1Amp).

)° A 5V power source with a mini usb connector.

Start by screwing out all the philips screws in the handle.

Step 2: Opening and Taking a Look Inside

When you take the top part off you see the different parts the swatter is made of.

Indeed, not a whole lot.

What we see is :

The swatter pcb, the switch, the positive wire (yellow) and the negative wire (black) and the battery terminals.

Yes, you will be thinking those terminals look to be in good shape.... I first cleaned them but then the magic idea sprung to mind to upgrade it to Li-Ion.

Step 3: Preparing to Fit the New Battery

First thing to do is to get the old terminals out.

Just use your screwdriver and place it under the terminal and lift up, they will slide out of the plastic.

Take the complete swatter surface plus electronics out of the bottem holder part.

You now need to remove the plastic parts that are in the way for the new battery.

You can break these parts out with some pliers. I used a pair of flat nose pliers.

Holding it right at the bottom you can cleanly rip them out one by one.

Et Voilà, space enough for the new battery.

The 18650 battery:

The battery I used is a 18650 model, one of the most used Li-Ion types around. I salvaged it from a laptop battery. Most of the time one or more cells in these battery packs go bad and you can't use it anymore in your laptop or other device. But when you open them up and use a multimeter to measure each one you will fast find the good and the bad ones.

The good ones still have a certain voltage left in them, the bad ones give zero 0 volt when measured.

I always cut them appart and keep some of the solder terminal on to make it easier to reuse them later. Like you can see on the last picture.

Step 4: Fitting the Charger Pcb

The charger pcb used is one foud on "Gearbest" or "Aliexpress". Just use the number TP4056 and chose the cheapest seller :-).

It has a mini usb connector to go to the power adapter. I used an old Blackberry power adapter since it had the correct connection.

At the back are the solder tabs for the battery and the device. Please make sure to solder to the correct polarity terminal and double check it. But for now we need to test fit it in the housing. There is space in the top part of the handle (with this model used).

When the battery is in place the charger pcb can go on top of the battery. The charger pcb was just a bit wider then de mounting posts so i had to trim them a bit with an exacto knife so the pcb would fit right between them.

Next step is to mark out where the openig for the usb has to come. Use a 3mil drill bit and drill two holes. Used the exacto to make the hole to size as you can see in the last picture.

Step 5: Soldering and Fitting It All In

Next step is to solder the battery terminals to the charger. Make sure you measure the needed wire lenghts.

I ended up replacing the used wires in the swatter since these are very flimsy and break easy.

Look at the pictures to see where the negative and positive terminals go. I can't stress out enough to check everything. These batteries can cause fire if you handel them wrong!!.

Step 6: Fitting the Battery and the Rest of the Internals

I used some strong glue at the bottom of the handle to glue the battery in place. You don't want this to come loose while in action....DANGER!

Next place the front swatter part back into its place and the rest of the electronics. The switch is always jumping out so ended up using some tape to keep it in place for closing.

Glue the charger pcb on top of the battery, usb facing to the rear and as close to the end of the handle as possible.

Let the glue set before closing the handle parts.

Screw all the screws back in and test fit the power adapter. If it is done well it will line up and the adapter will fit.

Since the charger pcb is very flat i did not need to do anything to the battery lid, it can close and lock into it's grip point.

Step 7: Final Result.

Plugging in the power adapter need to give the correct red charging indicator led light, if that one does not light up something is wrong!. Ones the battery is charged it will turn green. Then you are ready to go.

The voltage of these Li-Ion cells is a bit higher then the ones used before. Two AA batteries give out 3V, this cell 3.7 to 4 Volts. Not to worry, the simple passive electronics used in the swatter pcb can handle it without any problem. You'll end up with more zapping power.

And this setup last a lot longer than with the AA cells. Just make sure to charge it before you store it for a longer time. Li-Ion cell don't like deep discarging and loose capacity when this happens. So ones every few months (4 with my used battery) i hook it up to charge.

So my friends, hope you find the instructable handy enough the make your joymachine last longer! Happy zapping!