Hey everyone. Is there a shield available that's designed to be a current probe? If not, does anyone know of a board that can measure current and speaketh the serial?
What is your project ?
Measuring current can be in more than ten ways: AC, DC, with very high voltages, with very high currents, galvanic isolated, high side, low side, and so on.
Adafruit INA219 module: https://www.adafruit.com/product/904
The word "probe" seem to indicate a clamp to measure the AC current.
Then you have to sample with a higher sample rate, to keep track of the 50/60 mains frequency.
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What is your project?
Measuring between 0 - 3mA at 200V DC. I'll take a look at the link you provided, thank you.
Looks like I'll need to make a some mods if I want to get .1mA resolution. But not sure that board supports 200V.
A hall effect current sensor is galvanic isolated.
See for example the ACS712 or the ACS723 : https://www.sparkfun.com/products/14544.
In a real circuit they can be 20% inaccurate, because the hall sensor is influenced by many things.
I think you need a shunt resistor to measure the current.
You need a: high voltage high side current sensing amplifier
I don't know if they exist. TI shows a circuit to use a current amplifier that is up to 36V and use that for a voltage up to 400V: https://www.ti.com/tool/TIDA-00332.
Alternatives:
- Use a shunt resistor with a high value and measure the voltage before the shunt with a voltage divider and the voltage after the shunt with a voltage divider. Can you allow a 10V voltage drop over the shunt resistor ?
- Use a Arduino board with a shunt resistor and a current amplifier at 200V (The whole board at 200V, with its own power supply or a battery) and transmit the data wireless to the normal Arduino board.
I hope someone else know a better and simple solution.
[ADDED] If the current is that low, does the voltage drop when a voltage divider is used to measure the voltage ?
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What are your thoughts on using a transducer? I'm finding transducers that can measure a large range of current which has me skeptical about getting accurate measurements for current as low as what I'm looking for.
If you mention something, please give a link to it.
A DC current transducer that can measure small currents without the inaccurate hall sensor ? Does that exist ?
If I find something, I'll send you a link. Right now I'm just speculating based on datasheets I'm reading of various transducers.
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