haha, thats so cool. not only is high voltage involved, but you get to kill something with it

Posted at 11:08 pm on Jan 9th, 2008 by tony

My friend has a “mouse problem”… maybe I’ll up the voltage a bit and help her out :)

Posted at 11:18 pm on Jan 9th, 2008 by The Steven

Why didn’t you just use a 555 timer in astable mode?

Posted at 11:27 pm on Jan 9th, 2008 by Fatom Phreak

it’s gonna smell like bbq’d dog hair…

Posted at 11:58 pm on Jan 9th, 2008 by jimmys

I think a microcontroller here would normally be referred to as “overkill”… no pun intended

Posted at 12:23 am on Jan 10th, 2008 by thethirdmoose

does it work? if i was still in my bronx apartment, i could have tested. the roaches were everywhere. my mom bought me one of those “ultrasonic” things that were supposed to scare away the roaches. i tried it for a few months and of course it did not work. i opened it up to see what made it tick. there were roaches living inside it.

Posted at 12:42 am on Jan 10th, 2008 by mikedd

nice project! finally, an excuse to get back into hobbying ;)

Posted at 1:24 am on Jan 10th, 2008 by cloner

heeeere kitty, kitty, kitty…

Posted at 1:47 am on Jan 10th, 2008 by jason

I don’t think the electric pulse will be fatal to insects… The “what seems to be” gold trace on the pcb seems to be of enough conductivity to transmit the full 400V pulses to the insect but with it’s carapace, the insect will not absorb enough current to kill, therefore just sort of paralysing it. It’s the same principle as the taser gun; a lot of tension but very very few current passing through the body resulting in a stun/paralyse state instead of death. Current kills, voltage sort of paralyse (to be simpler because on a medical term I don’t think it’s imsple as that).

I’d really like to see proof that this thing actually kill.

Posted at 1:56 am on Jan 10th, 2008 by BennyBoy

This sounds like a recipe for a roach on fire – a dead roach will just sit there and smoke, no way to remove it!

This needs an motorized paddle to move across and wipe the dead roach into a bin! True automated killing – you have a few extra lines on that PIC, right? When C1 takes a big voltage hit charring a roach, finish frying it for an extra second or two and then activate the wiper.

@bennyboy: well if it’s only stunned and not dead – wipe it into the bin… then activate a crushing device, heh heh heh :D

I was going to build something like this out of an electric swatter to deal with my fruit fly problem – unfortunately a simple trap made out of a bottle and vinegar made short work of them, with no satisfying sparks or loud bangs necessary :(

No cleanup mechanism necessary for fruit flies… they just fall through the mesh.

Posted at 2:11 am on Jan 10th, 2008 by Rectifier

Anyone here read “The Wasp Factory”? All of a sudden I’m reminded of it… :)

Posted at 5:34 am on Jan 10th, 2008 by PKM

“In order to consrver power, a zener was used in place of the usual 5 volt regulator. This allows doing extra tricks with the sleep mode for extended battery life.”

Er. What would these be? I don’t see how a zener diode is a better choice of 5V source than, say a linear regulator (assuming a low quiescent current).

WRT using a 555 – you could but I’d favour the programmability of a PIC. Also the A/D allows the voltage to be measured and it’s always handy to have a spare I/O here or there.

Posted at 7:02 am on Jan 10th, 2008 by SomeBEng

I think I would probably have to go with some form of a capacitor discharge system. I could yank a couple photo flash caps from some disposable cameras, which would give quite a bit more current that what’s being provided here. Certainly enough to kill a roach I would think, and very possibly mice as well. Hmmmm…

Posted at 9:41 am on Jan 10th, 2008 by Johnny B. Goode

Why not just make a board with traces like the one above and connect it to 120vac.
Guaranteed crispy critters !

Posted at 9:41 am on Jan 10th, 2008 by RAID

Probably dont need much current to kill a roach. kind of like those electric flyswatters; you can smack your friend with it and make him scream like a little girl, but it wil set a fly on fire if you keep the juice going. I believe those use cheap little transformers for voltage amplification from a 9v battery with constant voltage as opposed to pulsed.

wouldnt really need a body removal system either, the little fellow would just cook until he doesnt conduct anymore (i.e. burnt to a little briquette)

Still love to see it in action.
come one man… trip to the petstore… a feeder pinkie? maybe a handful of crickets?.. a pinkie?

Posted at 10:06 am on Jan 10th, 2008 by Rangerx52

i figure an insect’s legs should make excellent physical contact with the surface considering how sticky the feet are. as for how conductive they are, i’d like to know. see if you can get a roach and a multimeter. also, i’d absolutely love to see this thing on youtube.

Posted at 5:07 pm on Jan 10th, 2008 by will d

The only failsafe protection is a blow capacitor and a blown diode. No switch?

Also, couldn’t you convert this to a micro stungun?

Posted at 5:38 pm on Jan 10th, 2008 by Bryon Wright

hmmmmmmmm I wonder if you could use this to keep the dogs from raising their leg in your yard?????

Posted at 8:09 pm on Jan 10th, 2008 by Mike

to really be effective, it needs to use a voltage on the order of thousands of volts. most bug zappers run in the 5 to 15 kilovolt range.

Posted at 5:44 pm on Jan 11th, 2008 by fentanyl3

That looks so fun. Never tried etching a board before.

In the above comment, someone mentioned using a 555 timer in astable mode, I think 555 timers are easier to find and doesn’t need programming. Has anyone developed a more “efficient” version of this device?

Sure seems like something nice to leave in the corners to keep the bugs in check.

Posted at 6:09 pm on Jan 12th, 2008 by awdark

I built a similar roach motel back in the 1980’s. Mine was powered from a 9-volt battery. It used a 555 timer to create a square wave, that was fed into a step-up transformer. I was getting over 200 volts out of the transformer. The output was wired to two copper clad boards, which were laid on the floor so the roaches could then crawl over and complete the circuit through thier bodies..

We saved a lot of money at the grocery store that way.

Posted at 4:09 pm on Jan 17th, 2008 by Clint Schirard