# Frequency Input

I am new to the Arduino world, and would like some help with which board I need for my project. I need a board that will accept a frequency input both sine and square wave with a voltage range of 5mV to 12V . Will I need separate boards for Ac and DC?

Thank you

Welcome to the Arduino forum. That is good information, but we really need to know what you intend to do with the signal. Based on what you wrote, both signals are AC. One is sine and one is square. Is that connect?
Paul

If it is DC then it hasn't got a frequency.

What do you mean by "accept"?

What do you want to measure, voltage or frequency or both?
If it is frequency what range of frequencies do you want to measure?
If it is voltage what sort of voltage do you want to measure?
It could be, peak, peak to peak, avrage or RMS.

That is too wide for an Arduino with a 10 bit A/D converter. You need at least a 12 bit A/D and possibly a lot more. Especially if you want any degree of accuracy of measurement at the lower end of the voltage range.

Normally in a frequecy meter a high speed comparator would be used to convert the input to a clean logic signal - this then goes to a counter module (or microcontroller). What frequencies do you need this to work for? What source impedance (or what's the source of the signal?)

Thank you for replying, I do custom meter proving and developing a new way of calibrating meters. The frequency(meter pulses) I will be collecting can either be square or sine wave form with a range of 0-5000hz. Just measuring frequency.
I am looking at the Portenta board as I need to have analog inputs for measuring temp, pressure, and density of the product being calibrated. I also need to control the prover unit to tell it to launch and return. I also need it for a start and stop timer as well as a counter.
As for the voltage I can always use an amplifier along with a conditioner the keep a steady 5 volts and to clean up any noise.
Thanks again

Can you explain more about what you mean by proving?
Do you mean providing?

I don't know anything about the Portina board but there are a couple of ways of expanding the measurement range with the regular Arduino... It has 6 analog inputs so you can use multiple inputs, each with a different voltage divider.

All inputs do need to be protected from anything over 5V. It also needs to be protected from negative voltages so you either have to bias the AC signal or "kill" the negative half.

There is also an optional 1.1V reference which gives you about 1mV resolution with the 10-bit ADC.

It's "hard" to make any kind of scientific/engineering/measuring equipment that's as good as what you an buy and anything used in a regulated environment has to be calibrated by an independent NSTS certified-traceable lab.

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