few questions...

[FauDrei]

Regards.

Interesting project that made me want to upgrade my fly swatter too. I also have a swatter with voltage quadrupler output stage (as far as I can recognize circuit topology).

If you are inclined to answer - I have few questions:

• How did CBB 105J2000V output capacitor turned out to be? It seemed strange to me to replace the "fried" capacitor with 10x bigger one. As I understand, the only difference in your design with 105J2000V was adding bleeder resistance (2x 10 MOhm serially connected resistors in parallel with output cap. Does swatter still function to your satisfaction?

• Why not use two 2000V CBB in series as output capacitor? Yes, spacewise it requires some inventive positioning (some elements moved under PCB) within swatter handle, but it might be doable.

• My swatter has originally 3x 22 MOhm 1/4 W SMD resistors in series acting as an 66 MOhm bleeding resistor. You mention adding 20 KOhm resistor to your two 10 MOhm ones as 1/1000 voltage divider. How exactly had you meant to connect it? I am thinking how to create an 1/100 measure point in my swatter, but I am not sure how.

• Do capacitor sizes in voltage quadruple stage matter? I mean - my swatter has 2x 331 3KV ceramics near the transformer and 2x 222 3KV ceramics near the output CBB capacitor. In some designs, I read, smaller near transformer capacitors define the current from the transformer. What would happen if I swapped all four capacitors in quadrupler stage with 4x 332 6KV ceramics?

Finally - thank you for the inspiration and detailed explanations of the ideas and the problems in implementations of those ideas. Regards.

V3

[ristomatti]

Here's another one who wants to give thanks for this page! This inspired me to experiment with improving a bunch of swatters.

I'm only a beginner level electronics hobbyist so what I've ended up doing is much simpler. However I've found pretty satisfying results by replacing the original boards with a modules like this https://www.aliexpress.com/item/32988989449.html but on some I've used the original board. Every single swatter I've bought so far have had pretty much the exact same board inside which gives less output voltage. I've experimented replacing the output cap with adding one or more 2000V 105J CBB capacitors in parallel configuration. At most I've been able to fit four of them in parallel in the standard handle. I had to cut parts of the plastic out to make them fit.

I suggest trying different configurations as I've noticed sometimes less is more. More capacitance makes the swatters effective enough to kill big flies and even wasps (one zap might not be enough though), but on the other hand takes a lot longer to charge up (several seconds). Higher voltage can pretty much evaporate smaller insects and gives a loud bang that might leave ears ringing if used indoors. In my experience it doesn't necessarily make the swatter more effective though as the voltage created by the standard PCB is already enough to overcome the resistance of the insects.

Initially I didn't bother adding a bleeder resistor but on later ones I have. Initially I tried adding a single 100M glass resistor but it made the swatter less effective. Two 100M in series worked much better, although I still I think the two first ones without them are more effective. There's an advantage to this as with the bleeder resistor, you'll need to keep pressing the trigger constantly causing the transistor on the board eventually overheat. Another advantage is that you can just leave the charged zapper on the table and it can zap a difficult to catch fly if it happens to make the unfortunate decition to land on the bat. The downside is of course having to remember to discharge the swatter manually using a screwdriver.

I've found the board I linked works pretty nicely with just the standard two AA batteries but most of the time I've been using a single AA sized LiFEPo4 battery together with a "dummy" AA battery. In the swatters I've modded, Li-ion battery raised the voltage too high and the swatter began to occasionally arc by itself.

The mod is definitely worth it! Without modding the swatters I've found here are not even called electric fly swatters on Finnish, they're called electric mosquito swatters (the only thing they're useful for). Using traditional fly swatters is messy and since the mod, I've never had to use them anymore. Have fun experimenting!

[FauDrei]

Regards @ristomatti and thanks for your comments/additional information.

I will kindly ask you for few more URLs:

• Where did you manage to source CBB 105J2000V?
• What fly swatter models did you mod?

Namely, I have trouble sourcing anything above 474J2000V and have very limited space in the two swatters I currently own.

Thanks again.

V3

[ristomatti]

Where did you manage to source CBB 105J2000V?

It was this AliExpress seller https://www.aliexpress.com/item/1005001810062381.html but I've ordered from others as well (not all have 105J though).

What fly swatter models did you mod?

I've bought them at local (= Finnish) budget shops from 3 to 8€. Regardless of the store, they all seem to have the same internals and roughly the same shape. Something like this https://www.amazon.de/-/en/Electric-Swatter-Catcher-Mosquito-Mosquitoes/dp/B09DPMR9FV

Have fun!