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Two 1M resistors for a voltage divider is high. You could add a capacitor (1nF or 10nF) to GND and the analog input. Could you try to find what the leakage current or the self-discharge current of the battery itself is? Then take a percentage of that, for example 20%, then calculate what resistor value the voltage divider should be. It does not have to be ...


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When measuring a voltage that is higher than the maximum rating, the voltage of interest is tied to ground with a voltage divider. When measuring a negative voltage, you instead have to tie the voltage of interest to the positive supply voltage (study the answers to this question). In theory you can use the internal pullup to spare one resistor, but I would ...


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Duncan's answer is how I would do it as well. Indeed that is how I did do it as well. Having said that the challenge I had to work out was how to mix the voltages. For me, this was the hardest part of the project as I had little idea about current and voltage. I also wanted to use just one power supply. So what's the problem? The LED strip requires 12V@...


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As others have said, an Arduino pin can't handle 12V, and can't handle anywhere near 10A of current directly. A digital pin on an Arduino is limited to 20mA, or 1/500 as much current as you need, at 5V, which is less than half the voltage you need. If you try to connect 12V to a pin on an Arduino pin you will almost certainly destroy that pin, and may ...


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I guess that you are showing the voltages there directly calculated from analogRead() and that you connected the AC voltage directly to the analog input (and it's ground with the Arduino's ground). The reference for every communication/voltage measurement/digital input is ground. Naturally the Arduino can only measure voltages inside of it's own supplied ...


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The AC voltage that you are trying to measure is about 50/60Hz depending on where you live. And the maximum effective sampling rate for a regular Arduino ADC is 9615Hz. This means you're not going to experience any aliasing as the sampling rate is well above the 2 * Signal Frequency. The values that are coming out of analogRead() are raw ADC values which ...


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