Implementation of a simple number counter for a mosquito zapper

Thread Starter

dennipeter

Joined Oct 13, 2020
9
Hello folks,

I am a designer from India trying to make a mosquito zapper that keeps count of the number of mosquitos killed.

I am trying to implement a number counter to the circuit of a readily available mosquito zapper bat (Image below).

IMG_20201013_233050.jpg
IMG_20201013_233223.jpg
IMG_20201013_233202.jpgIMG_20201013_233135.jpg



I want to do this using an arduino nano or an ESP 32 chip. Essentially, each time the zapper zaps a mosquito, I want it to send an input into one of the digital pins of the arduino.

The capacitor at the end of the circuit reads 2000v. I assume this is going to be the output voltage between the steel meshes. I do not have a high voltage multimeter to verify this. I am unsure about how to convert this into a safe voltage spike that can be read by the arduino's pins.

Apologies if this is a noob question.
 

AnalogKid

Joined Aug 1, 2013
8,676
Photo of the underside of the board. This will tell us if the magnetic component is a transformer or an inductor, and if either side of the 2 kV output is referenced to the input ground.

You probably can form a differentiator / edge detector / attenuator with a small, high-voltage rated capacitor and a resistor, plus a diode to keep the signal within the Arduino input voltage range. This should make a narrow spike pulse with each zap.

ak
 

Thread Starter

dennipeter

Joined Oct 13, 2020
9
Photo of the underside of the board. This will tell us if the magnetic component is a transformer or an inductor, and if either side of the 2 kV output is referenced to the input ground.

You probably can form a differentiator / edge detector / attenuator with a small, high-voltage rated capacitor and a resistor, plus a diode to keep the signal within the Arduino input voltage range. This should make a narrow spike pulse with each zap.

ak

Thanks @AnalogKid for the quick response.

Here are some more pictures of the mentioned part.
Untitled-1.jpgIMG_20201014_023414.jpgIMG_20201014_023406.jpg

Could you point me in the direction of a similar example/ link / video explaining how to wire the mentioned differentiator circuit. The concept is new to me. I am not an electrical engineer by training.
 

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jpanhalt

Joined Jan 18, 2008
10,463
Hello folks,
I am a designer from India trying to make a mosquito zapper that keeps count of the number of mosquitos killed.
Obviously, you have never been to Minnesota. There, they keep score of the number of mosquitoes killed in a single zap. Your device might be useful in the antarctic.
 

Dodgydave

Joined Jun 22, 2012
9,637
Looks like the HV comes out of the transformer into a bridge rectifier using 4 diodes and a smoothing capacitor,into the Green and Red wires.

Is this fed from AC and DC voltage, as there are two bridge rectifiers ?
 

Thread Starter

dennipeter

Joined Oct 13, 2020
9
Looks like the HV comes out of the transformer into a bridge rectifier using 4 diodes and a smoothing capacitor,into the Green and Red wires.

Is this fed from AC and DC voltage, as there are two bridge rectifiers ?
Yes, you are right.
From what i have learnt. There is a cheap rechargable 3.3V battery inside. The transformer increases the voltage to about 300V, and then the capacitor increases that further to about 2000V.

I am not if the transformer, in the process converts to AC.

You mentioned that there are two bridge rectifiers with 4 diodes each? But I only see 3 diodes after the transformer.
 

sghioto

Joined Dec 31, 2017
1,553
I have never used one of these devices ,when a bug gets zapped does it make a loud pop?
If so wondering if a sound sensor might work.
 

Thread Starter

dennipeter

Joined Oct 13, 2020
9
I have never used one of these devices ,when a bug gets zapped does it make a loud pop?
If so wondering if a sound sensor might work.
Yes,I did think of putting a sound sensor. But that did seem a bit rudimentary. Also, external sounds may be able to trigger the counter.

This thing works like a regular electric fly zapper, only change is in the form factor, and you can wave the bat around to hit the mosquitos.
 

sghioto

Joined Dec 31, 2017
1,553
I see three diodes and three capacitors. Might be a voltage tripler circuit but that would mean 800 volts off the transformer.
Yes,I did think of putting a sound sensor. But that did seem a bit rudimentary.
That might be your best option as far as isolating the bat from the arduino. Another idea is a sensor that will detect a "vibration" of sorts when the bug gets fried. Maybe a piezo sensor.
 
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Thread Starter

dennipeter

Joined Oct 13, 2020
9
I see three diodes and three capacitors. Might be a voltage tripler circuit but that would mean 800 volts off the transformer.

That might be your best option as far as isolating the bat from the arduino. Another idea is a sensor that will detect a "vibration" of sorts when the bug gets fried.
Thanks you. Appreciate the input.
Is there not any other way to make a parallel circuit that can detect a large voltage spike in a nearby circuit?

I'm still waiting on a reply from @AnalogKid. But what do you think about his suggestion in post #2?
 

sghioto

Joined Dec 31, 2017
1,553
But what do you think about his suggestion in post #2?
I would like to see that circuit as well.
Without a bat on hand it's difficult to know how the high voltage output changes when a bug is hit. I would think there would be a measurable drop and that would be useful. Either way using sensors or voltage differentials you are going to have to do some experimenting on the device to get the needed data.
Personally I think the piezo sensor idea is worth a look.
 

Thread Starter

dennipeter

Joined Oct 13, 2020
9
I would like to see that circuit as well.
Without a bat on hand it's difficult to know how the high voltage output changes when a bug is hit. I would think there would be a measurable drop and that would be useful. Either way using sensors or voltage differentials you are going to have to do some experimenting on the device to get the needed data.
Personally I think the piezo sensor idea is worth a look.
Thanks, Didnt think of a piezo electric sensor. Can try experimenting with that.
 
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