Electric Fence voltage monitor 10Kv - 5v

A little off Topic. I am looking to get a small Circuit designed. Unfortunately I have been a little too long out of the raw electronics area. So am looking for advise. Either for a recommendation to do the design or parties interested. There are similar devices on the market but are too expensive for my taste or have to many features. Which makes the unsuitable for my overall project concept.

Require Circuit to measure electric fence voltage.

Input is approx 10Kv pulsing at on for several milliseconds once a second.

Circuit is to step voltage down to max 5v (suitable for input to a Arduino)
Sensing circuit to include opto islolation between 10kv input 5v output as well as overvoltage protection.

Given the large range of Energizers available a full wave bridge rectifier should also be included.
Consideration to a peak hold circuit that resets every 4-5 seconds (user selectable on/off/rate).(this may even be able to be handled by the Arduino)

Focus to given to lowest possible cost of components. All resistors are to be rated to withstand the voltages exposed to at their location in the circuit.

PCB design would also be useful giving consideration to clearances to ensure no tracking between HV input terminals and other components.
No read out display is required in this design.
Device will be permanently connected to the fence, so input impedance should be sufficiently high enough not to be seen as a "short on the fence"

Factors to consider: Small footprint, Low cost components, easily reproduce-able, if active components are required low power consumption. (device will be powered by solar rechargeable battery)

Deliverables include: Circuit diagram, Bill of materials, PCB design, explanatory notes, component cost, proof of functionality.

Thanks In Advance.

What are you using the monitor for, is it outputting to another device?

The first thing is a high voltage divider. EBG Resistors. Put it in a potted module.
You could make your own here.

Jonnie_R said:

What are you using the monitor for, is it outputting to another device?

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Yes it will be outputting to an Arduino.

Why not just buy one of the many voltage testers on the market and modify that to give an output to the Arduino instead of displaying it on the LCD?

Gallagher, Nemtek and others make one as I'm sure you are aware. Unfortunately I have no PCB experience but I am interested what you are trying to achieve as I design and maintain fence systems in the UK that use Gallagher equipment. I do know someone in the UK who may be able to help though.

Jonnie_R said:

Why not just buy one of the many voltage testers on the market and modify that to give an output to the Arduino instead of displaying it on the LCD?

Gallagher, Nemtek and others make one as I'm sure you are aware. Unfortunately I have no PCB experience but I am interested what you are trying to achieve as I design and maintain fence systems in the UK that use Gallagher equipment. I do know someone in the UK who may be able to help though.

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I will ultimately be adding the values to a Wireless mesh network to be displayed back at base/Web.
On my farm i have multiple energizers (Manufacturers) and fence segments. so i would like to be able to monitor each segment before and after the various isolators around the farm.
I have been looking at the various testers and feel the circuits have too much going on and at $160 - $ 200 makes them too expensive to do what I want.
at each location there would be a minimum of 2 fence inputs (Line and Load side of the switch) up to 4 fence intersections.
For future mapping display i will be adding GPS location information as well.

Plan at the moment is for the Arduino to collect the raw input value and transmit via a Lora mesh back to base which will then do all the scaling, alarming and web display. By doing this I can use the same end nodes to transmit tank levels, pump statuses etc as well.

I had a look at the Gallager iSeries stuff which is way too expensive and restrictive for my needs.

As for modifying an existing unit, I would need to reverse engineer the circuit and would still end up with something too bulky for my needs.

The whole project hinges on if I can get the cost of the 10Kv to 5v interface low enough.

Cool interesting little project.

The circuit design is probably going to be a reasonable chunk of money. Have you tried www.eng-tips.com as they have a specific forum dedicated to circuit design?

Jonnie_R said:

Cool interesting little project.

The circuit design is probably going to be a reasonable chunk of money. Have you tried www.eng-tips.com as they have a specific forum dedicated to circuit design?

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Not yet but will look into it thanks

Maybe use something like this - modify it to get signal(s) out for use in Arduino.
Use the LED connections?

https://www.amazon.co.uk/SODIAL-Vol...6214405&sr=8-6&keywords=electric+fence+tester

I have no experience at this voltage level but could you wrap a wire around the fence wire and measure the pulses that way? It’s more of a way to measure current but then maybe you could get away from high voltage components except for what touches the fence?

As ndzied1 implied, don't have a direct connection to the 10kV, I know that Arduinos are cheap but you will blow up a lot of them. And likely as not you will break the electric fence, they are designed to be very low current otherwise you would have dead livestock and farmers.

A change in voltage causes a change in magnetic field, a moving magnetic field will induce a voltage in a wire that is in the magnetic field, check out Faraday's Law. So a suitable insulator for the 10kV with a few wraps of wire will give you an induced voltage that you can measure. Remember that the magnetic field weakens as the cube of the distance so it will be a balancing act to get to a safe distance and the number of wire wraps needed to still be able to measure the voltage. You can take a stab at the 'safe' distance by looking at the insulators that are supplied with the electric fence kit.

BryanG said:

A change in voltage causes a change in magnetic field, a moving magnetic field will induce a voltage in a wire that is in the magnetic field, check out Faraday's Law. So a suitable insulator for the 10kV with a few wraps of wire will give you an induced voltage that you can measure. Remember that the magnetic field weakens as the cube of the distance so it will be a balancing act to get to a safe distance and the number of wire wraps needed to still be able to measure the voltage. You can take a stab at the 'safe' distance by looking at the insulators that are supplied with the electric fence kit.

Click to expand...

I was going to say this or perhaps an analog hall effect sensor? It would still require some isolation from the Arduino potentially with an amp-op as comparator or so, but could be an option.

ndzied1 said:

I have no experience at this voltage level but could you wrap a wire around the fence wire and measure the pulses that way? It’s more of a way to measure current but then maybe you could get away from high voltage components except for what touches the fence?

Click to expand...

I will also be looking into current measurement as well as it can also provide information about the overall health of the fence.there are a number of clamp on CTs that can do this.

BryanG said:

As ndzied1 implied, don't have a direct connection to the 10kV, I know that Arduinos are cheap but you will blow up a lot of them. And likely as not you will break the electric fence, they are designed to be very low current otherwise you would have dead livestock and farmers.

A change in voltage causes a change in magnetic field, a moving magnetic field will induce a voltage in a wire that is in the magnetic field, check out Faraday's Law. So a suitable insulator for the 10kV with a few wraps of wire will give you an induced voltage that you can measure. Remember that the magnetic field weakens as the cube of the distance so it will be a balancing act to get to a safe distance and the number of wire wraps needed to still be able to measure the voltage. You can take a stab at the 'safe' distance by looking at the insulators that are supplied with the electric fence kit.

Click to expand...

I am confident the voltage level to the Arduino can be managed, given the digital read out testers use "Electronic" level voltages. There will be provision for over voltage protection and voltage levels will be tested before being applied to the Arduino.
As it is a Pulsing voltage using the coil method opens up potential issues with Back EMF. (extra complexity).
The coiled wire method would work to some extent but simplicity of install and repeatability of measurement may not be satifactory.