Electric mouse/rat trap power supply

[redwire]

Electric mouse/rat traps on youtube, and I was trying to figure out the power supply to buy one. There are loads of fake videos with 12V battery + 150uF 450V cap in parallel... the HV PSU is hidden.

I saw this PSU which has weird RGB led flashing and possibly a timer and shutoff. Closest I could get to it is a "DC-DC 3.7V Step-up to 1500V-2000V-1800V High Voltage Pulse" but it does not have the extra circuit (MCU?) seen in pics. I think a timer or something like a fencer is needed.

Other youtube vids use a (hidden) boost converter with 10-150uF 450VDC cap charged up, across the electrodes.
I was not interested in tasers because of the fire hazard with an arc and the stink.

Anyone recognize the board or know the name for it?

https://www.youtube.com/watch?v=z6eCdehmKdI

[stj]

Re: Electric mouse/rat trap power supply

fluffy animals,
you probably need "arc power" to get through the fur.
it's not like shocking humans.

[eccerr0r]

Re: Electric mouse/rat trap power supply

Effectively it is a taser PSU. Tasers don't really have that much power, it's not like it has any range. If it's too weak or just a one shot, it effectively just becomes a "don't go here". In fact the capacitor discharge ones in electric fly swatters tend to stun but not kill insects.

You need the power to fry if you want them dead. Granted most of the time it will go through their paws so you don't have to deal with fur...

[redwire]

Re: Electric mouse/rat trap power supply

What throws me off is the youtubers all hiding their power supply, to keep their fame and glory, and youtube's censorship of anything mean like an arc.

The feet and tail seem to get the jolt. The critter collapses on the electrodes, then shorts out the PSU, so you'd need something to flip empty the board.
Some guys use wire mesh spikes to get through the fur.

I can't tell if 450VDC or 2kVAC is better.
High voltage the mouse can tell from corona on the whiskers.

[RJARRRPCGP]

Re: Electric mouse/rat trap power supply

What throws me off is the youtubers all hiding their power supply, to keep their fame and glory, and youtube's censorship of anything mean like an arc.

I never saw YouTube having censorship with arcs. I bet Scripps TV shows have more censorship than many YouTube videos, LOL.

[eccerr0r]

Re: Electric mouse/rat trap power supply

Just like a static electricity spark will just startle people, same with rats. Need to feed power through their body to stop their heart and that'll kill them by suffocation effectively.

I don't know why they hide the power source.

I don't know why they also don't ban mother nature's sparks (i.e., lightning...) if they do censor sparks. You don't need to have a visible spark to kill, though it adds to the effect...

[redwire]

Re: Electric mouse/rat trap power supply

Youtube does not allow "content where there is infliction of unnecessary suffering or harm deliberately causing an animal distress" or something like that, some viewers complained about the cute pest getting killed.

Mousetrap Monday had to censor the mouse dying scenes, add cushion padding so they hit softly etc. He still posts unedited vids on his website to see the details.

It is a problem for me to see how HVDC vs AC and voltage, what the effects are, instead of setting up a camera.
Best seems to be shocking the mouse/rat feet so they jump into a water bucket and drown.
So the PSU could always be running but some seem to sense resistance then turn on the juice, to save battery life. I think I'd add an overcurrent shutdown after 20 seconds in case something got trapped on the electrodes, so it doesn't damage the PSU or burn something.

It would be less than an electric chair and more than a few mA.

[lax luthier]

Re: Electric mouse/rat trap power supply

I have a Victory electronic mouse/rat trap. It has a stated output of 4,000 Volts. Runs off 4 size C cells.
Works through the feet, not the fur.
Very effective. Use Tootsie Roll candies for bait.

[redwire]

Re: Electric mouse/rat trap power supply

The little stun gun HV modules "1000KV" or "30KV" overheat and die if run for even 30 seconds. Or they arc over inside with no gap to limit.
They are all one-transistor saturated-core DC-DC with HV multiplier at the output, in other words big long arcs but little current. Igniter ones have lower V and higher (hotter) arc current. BigClive had some beers and tried touching one lol he swears pretty good.

It looks like I need something to sense mouse feet on an electrode, then turn on the HV power supply for ~15 seconds and then switch it off and keep it off if something is still on the electrode. The HV power supply would have to be OK with nothing there, and no arcs on the wood to burn down the building.

Victor did a rev. 2 of their electric mousetrap, easier to clean after the Mousetrap Monday review.

[goontron]

Re: Electric mouse/rat trap power supply

Sounds like a chinese ATV ignition coil and ignition coil driver is what you need. Nice hot arcs.

[lax luthier]

Re: Electric mouse/rat trap power supply

Sounds like a chinese ATV ignition coil and ignition coil driver is what you need. Nice hot arcs.

If you can detect a mouse or rat's presence and trigger the HV output, you won't need 15 seconds to do the job. Do you have the Victory schematic?

[goontron]

Re: Electric mouse/rat trap power supply

If you can detect a mouse or rat's presence and trigger the HV output, you won't need 15 seconds to do the job. Do you have the Victory schematic?

I do not, however if you watch mousetrap monday, you will see 3 plates. I suspect one common ground, one "b+" so to speak, and one capacitive sense plate that feeds back to a microcontroller.

So essentially what you have is a microcontroller that does the detection/lockout/alarming and simply switches a high-voltage power supply. The micro may also do the driving of the high-voltage boost converter, but i'm not entirely sure. I say this because in many videos you can see arcing. I suspect its quite a bit less voltage then the many Kv an ignition coil would generate, but for sake of simplicity, something modular like that would be beneficial for a homebrew design.

As for the video posted, if you look at the board, it's a boost convertor with some gimmicks (EG: LEDs). You can see a swichmode layout for the initial power conversion. Educated guess, that ferrite core transformer on the board runs at 10's of Khz, and puts out 300-400v and at the output of the capacitor doubler is 600-700v. Quiescent current on these supplies is probably around the range of ~100mA, so they can run for a small while on a 12Ah UPS battery.

One thing i notice in common on all of these, is the muscle spasms don't match that of an AC waveform, but a dirty DC waveform, which also supports the doubler theory.

Now, having less voltage here, like the suspected 600v is beneficial because, while higher voltage has more chance of overcoming resistance of fur and skin, if its too high you will get coronal discharge, which will be felt by the pest in question and may deter them.

The microcontroller based design has a number of benefits:

First and most obvious, its puts magnitudes less strain on the battery and boost convertor.

Second would be that, should tracking occurs between the high voltage terminals, the microcontroller can time out and prevent a fire or other damage from occurring. It also prevents the pests carcase from burning, which i can say from personal experience is a horrible smell.

Third being, higher voltages that would cause a corona can now be used since the boost convertor is not active until a verified pest "load" is in place.

Fourth is cost savings. The micro can do... Well, everything. Battery management. Acting as the switch mode oscillator. Status indication. and pest detection, of course.

Now, i suspect that of you were to open a Victor style electric trap, you would find a board or two, consisting of a microcontroller, driving a boost convertor much like what you see on those boards, in those videos. Ferrite core transformers and all. Or you may find potting compound. One of the two.

[goontron]

Re: Electric mouse/rat trap power supply

I stand corrected on the output of those high voltage inverters. I managed to find one on ebay that look exactly the same and claim output voltages closer to that of 1-2kv.

https://www.ebay.com/itm/2000V-High-...t/112664892698

[redwire]

Re: Electric mouse/rat trap power supply

Couldn't find much for a decent teardown of the Victor.
Kept researching and found the patents for Woodstream Corp. that uses resistive sensing between electrodes, and here is the schematic they use.

"... Upon entry to the high output subsequence, step 530, the trap generates a high voltage killing cycle, step 532. According to a preferred embodiment, the high voltage cycle includes the generation of high voltage pulses having a peak magnitude of from about 4 kV to about 7 kV, and more preferably from about 6.5 kV to about 7 kV, and a duration of from about 23 usec to about 28 usec at intervals of about every 4.25 msec to about 4.5 msec for at least about 20 seconds. Upon completion of the killing cycle, the trap enters the check for kill subsequence, step 534.
Upon entry to the check for kill subsequence, step 540, the trap again checks to see whether there is an impedance between the killing plates in the range of about 10 k ohm to about 1M ohm, step 542. The absence of such an impedance indicates that the mouse escaped. In this event, the catch counter is checked to see whether it has a value greater than zero, step 544."