Max, whatever you do, never ever urinate on an electric fence. It can be a shocking experience.

Ron

I will keep that in mind!
The neighbours might object also

 

Is it possible that the original thread has just been hijacked? As of post #34??

 

Is it possible that the original thread has just been hijacked? As of post #34??

????? The post is entitled "How to make an electric fence??
All the content seems relevant to the subject.

 

Update on the fence project, the night camera caught some good pictures and videos of deer when they touched the wire.
Just a single solid galvanized wire was used about deer 'nose' level.
Ended up using an 8pin micro.
Unfortunately they are not the file type allowed by the site.

 

You should be able to post assembly or hex files as plain text on this site.

 

I meant the video of the captured event !

 

Tell us, Max, were the deer startled by touching the wire? Plain text will be acceptable.

 

Tell us, Max, were the deer startled by touching the wire? Plain text will be acceptable.

"Startled" would be an understatement!

 

I am looking to put one together for a short fence for deer.
I intend using an older AC Delco coil, from some out there on other sites, a 0.1sec pulse every sec appears popular.
20VDC and a Mosfet switch

max did you ever get this going? I’m interested in your design.

 

max did you ever get this going? I’m interested in your design.

Yes, very successfully, I used a mains transformer to drop down to 12vdc, I used a automotive waste spark coil to provide two short pulses every couple of seconds.
I could probably done it with a 555, but I used a small 8pin micro & Mosfet to fire the coil.
I have a wild-life camera set up, it shows a few very surprised deer that get it on the nose !!

 

Yes, very successfully, I used a mains transformer to drop down to 12vdc, I used a automotive waste spark coil to provide two short pulses every couple of seconds.
I could probably done it with a 555, but I used a small 8pin micro & Mosfet to fire the coil.
I have a wild-life camera set up, it shows a few very surprised deer that get it on the nose !!

I did see the mention of what you just said but I wasn't sure if that was the final form or not.

I gotta ask, for clarities sake, a waste ignition coil is just meaning a used one right? Any chance you’ve got a diagram handy?
So the pic micro works similarly as the 555 I take it?

 

Im sitting here looking at a, xr2243, a 5 wire cdi ignition module and a coil (both off an old atv). Need a deer repellant when I came across this thread.

 

I gotta ask, for clarities sake, a waste ignition coil is just meaning a used one right? What is an 8pin micro?

You would be correct, an old ignition coil from an automotive junk yard.

An 8 pin micro is just an 8 pin uC (micro-controller) which is an easy approach. A few lines of simple code and a micro like an ATTiny family or similar.

Ron

 

Yeah so.. how’s the coil being triggered?

 

Yeah so.. how’s the coil being triggered?

The coil is triggered using a MOSFET and low side switching. Think old coil ignition system and the coil fires on a negative going transition of a pulse. So we use a 555 timer chip or a uC (I prefer the uC) to drive an N Channel logic level MOSFET which in turn drives the coil primary side. Keep in mind we use a pulse because the coil needs to be driven High to Low very fast so we use a pulse as a sine wave will not work. Old cars used points (breaker points) and as the points opened the coil fired. About any logic level N channel MOSFET will work as long as it can supply the coil current. A FQP30N06L comes to mind as a MOSFET.

Ron

 

The very simplest fence charger would be a retired single automotive spark coil and a slow turn signal flasher. It might also need a ballast resistor or possibly an old auto headlight to reduce the current. Put the coil primary, battery, flasher and resistor all in series and each time the flasher opens there will be a spike of high voltage. The ground connection will be to the coil housing, and it would actually be a connection to a ground rod. Not the most efficient but it should give a nasty shock to whatever creature touches the fence wire.

Now about the mains powered fence chargers: I was given a half bushel of them to repair a few years back. A NASTY lightning storm swept thru an area and zapped the electric fences, which opened the secondaries of each transformer. No output was the symptom and an open secondary was the verification. The repair was to unsolder the transformer plastic coil form and the unwind the secondary onto a spool using a transformer winding fixture in reverse. The secondaries were thousands of turns of really fine wire in several adjacent banks of the plastic form. That is how they avoided arcing over. So the secondary would be unwound to the point of the break, sanded, soldered and a bit of tape over the repair and then rewind back onto the form. Amazingly they worked after being re-assembled. Those units used a CMOS binary counter clocked off the mains to trigger an SCR every few seconds. The SCR dumped about 175 volts from a paper capacitor thru the primary. So it was rectified mains powering the primary, but that was quite well isolated from the secondary.

I did not make money on that batch but I did teach a young person how to do it. I don't know if he went into the business but certainly somebody else is doing it now.
If I wanted a serious fence charger, I would use an oil burner ignition transformer and a thermal light flasher to charge the fence.

 

I gotta ask, for clarities sake, a waste ignition coil is just meaning a used one right? Any chance you’ve got a diagram handy?
So the pic micro works similarly as the 555 I take it?

The waste-spark ignition coil is used on modern auto's Rather than consisting of an auto-transformer with one spark plug connection, it has an isolated primary/secondary, and the two outputs are connected to two plugs, One is firing on one cylinder power stroke like normal, the other at the same time on a cylinder exhaust stroke, there are 3 coils on a 6 cyl motor.
Although I had both types of coils, I preferred to use the waste spark type due to the isolation it gave.
I will post the schematic.
The difference is that the micro is programmed to achieve the result, and the 555 would be with external R/C components.
I used one output for the fence, the other connected to the ground conductor.

 

Well I'll be and I figured a waste coil was just an old coil from a junk yard. Thank you Max for the clarification. I should have used Google.

Thanks
Ron

 

@skeer see this for a 555 version.

https://www.next.gr/power-supplies/high-voltage/HV-Ignition-Coil-Driver-using-555-l7670.html

 

I was entirely in the dark on wasted spark ignitions.. TIL for sure!

Probably a dumb question but.. N-channel FETS are not all the same right? I have a growing pile with datasheets that all say 'N-Channel Power MOSFET"
Second, while I do not have a wasted spark coil I do have a CDI ignition control box/coil off a single cylinder 100cc 4-wheeler. But having that won't really make things better will it? I mean I still need that pulse/square wave source to kick off both the coil and the module.. right? If so the module is just useless added weight.

Yesterday I happened to pull a Maxim 555 off an old deer feeder so I did spend an hour or two last night looking for those types of cirucits but did not come across anything that screamed 'TRY ME!".

The next.gr link above sort of works.. the article the guy published itself is empty, all you can get the the preview there in which he mentions people reported issues getting it to work.