# Tag Info

### How can I seriously calibrate ADC voltage readings with Arduino Nano?

Rather than mapping to a range of 0 to 4.4 V, map to the range 0 to 1.1 V and use analogReference(INTERNAL) to select the internal band-gap 1.1 V reference source. This reference voltage might vary a ...

### Lowest voltage applicable on AREF pin on Uno and Mega

According to the datasheet (page 375) the minimum voltage you are allowed to have as a reference voltage for the ADC is 1V.
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### The analog read is not giving the correct waveform as that of an oscilloscope

Your sampling rate is far too low for the signals you are looking at; you're not getting enough data points for drawing something that looks like the original signal. The Arduino library's analogRead()...
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Accepted

In a word, no. The Arduino uses a rather crude 10-bit ADC. If you feed it a small voltage reference, you can divide that small voltage into 1024 steps. (as you say, about 1.1mV/step) If you feed the ...
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### Cheapest and easiest Arduino board for 12 bit ADC, thinking of M0

Use a Teensy 3.x. Those have 13 bit ADCs
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Accepted

### Can i supply the AREF pin with an Analog pin from the same board?

With an input voltage between 0 and 2.2 V, you can use a 2:1 voltage divider to cut the voltage in half. In your code, use analogReference(INTERNAL) to set the analog reference voltage to 1.1 V. The ...

### How to interpret analog values sent to Arduino from line scanner?

First, a preliminary note: according to the datasheet, the only time you need a delay in your program is after reading the whole array and before sending the next sync pulse. All the other timing ...
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### How can I seriously calibrate ADC voltage readings with Arduino Nano?

Changed resistors to 100K/20K for the divider you probably want to read the datasheet about the impedance requirement on the source and potential solutions there.
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### Reading 4-20ma signal on arduino

Using a resistor is the "Normal" way, yes. 250Ω will give you 1-5V, yes, which means that you get 4/5 of the actual resolution of the ADC at your disposal. That means instead of 0-1023 you're ...
• 105k
1 vote

### micros() resolution for Portenta H7

The micros() language reference states that, "[The micros() function] returns the number of microseconds since the Arduino board began running the current program. This number will overflow (go ...
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### How would I go about measuring an analog signal on my arduino mega that has both positive and negative voltages

Here is my try at this: if your voltage source doesn't mind sinking something like 150 µA, you could try something like this: simulate this circuit – Schematic created using CircuitLab ...
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1 vote

### How would I go about measuring an analog signal on my arduino mega that has both positive and negative voltages

You need to amplify your signal and add 2.5V as a "virtual ground" for the amplification. This gets a little tricky, since you need a low-impedance VCC/2 source to feed the amplifier as a virtual ...
• 105k
1 vote
Accepted

### How can I seriously calibrate ADC voltage readings with Arduino Nano?

In my opinion, this is a very Arduino specific question. First of all, you can't map 22-30V to 0-4.4V with a voltage divider (unless you have a negative voltage available). A opamp introduces a ...
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