I am a software engineer by day and a pig farmer the rest of the time. I am looking at automating many of the mundane tasks around the farm by deploying IoT all around my farm. One of the first tasks is to gather the current voltage of my many hot lines scattered about the farm. The most powerful shock might be in the 8k volt range.
Is anyone aware of a ready made voltage sensor that could be wired into a Gadgeteer solution?
If not, how might I accomplish monitoring voltage this high in a manner that I could wire into a Gadgeteer solution?
Update
What is Gadgeteer:
This is a set of modules that can easily be plugged together to create something interesting. You can then deploy C# code to it via USB and quickly get a working thing up and running. In the case where a readily available module is not available you can use a bread board and wire in any other readily available circuit/sensor that is on the market. This tool set allows software developers to dabble in the hardware world.
What is a Hotline:
In this case I run a pig farm (among other animals to be managed). I keep the pigs in a paddock by surrounding it with a set of steel wires that is not directly grounded to anything. A pulse is fired from a (solar in this case) electric charge box every X seconds. The pulse without any interference for up to 30 miles worth of wire tops out at 8000 volts. When the animal touches the wire…and the ground…they get a good zap to teach them to step back. I have touched it a few times as have my kids…and it is a GOOD ZAP. I have basically this model charger: http://www.tractorsupply.com/en/store/zarebareg%3B-30-mile-solar-low-impedance-fence-charger
Do I need to measure for the exact voltage?
No – not really. I need to mostly establish a baseline. So if the 8k voltage was some other numeric value that I could establish as a baseline to be measured every hour or so that would be good enough. I need mostly to be able to collect data and then reason over it. If a fence was down I could pretty quickly get a notification for being way below allowable tolerances. But in the case that weeds grow up all around the fence the number of plant contacts over time would slowly but significantly impact the effectiveness of the fence. So baseline plus semi-accurate deviation would be good enough.
Best Answer
Measured inside the fence-charger case? Or you want hv probes out in the rain?
Easiest is to just buy a high-voltage probe for a voltmeter. These are just a thousands-megs resistor in a heavy insulator. Hook a 10meg resistor across your A/D inp, then put the HV probe between the A/D-inp and fence wire. A/D-common goes to earth. That reduces 8kv pulses to perhaps 8v or 0.8v. For added safety, perhaps put a chain of several 1meg resistors in series with that wire from A/D to earth. With the impedances you're dealing with, a chain of 1meg resistors is a good conductor.
But if lightning sometimes kills your fence charger, you're asking it to come in and zap your A/D block, or worse.