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Questions tagged [analogread]

A standard Arduino function for measuring the voltage on an analog pin via ADC.

Calling analogRead(x) (where x is a pin number) allows the Arduino to measure the approximate voltage on its analog pins. This is performed using a 10-bit ADC (Analog to Digital Converter), which takes approximately 100 microseconds.

It returns an integer value between 0 and 1023, which will usually represent the range +0v to +5v. However, the voltage range will be different if the board runs at a different voltage, or if the program has selected a different range by calling analogReference().

348 questions
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Analog Reference and Power Voltage

On the Arduino website it states that the analog pins read voltages from 0 to 5 volts (default) and return a value from 0 to 1023. One can also set the range with analogReference(). However, this is probably assuming the Arduino is running at 5…
user3933
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Does any board provide more than 1024 analog input values?

The Arduino boards provide an analog input range of 0V to 5V which translates to 0 to 1023 integer values. The range is determined by the on-board ADC, which in the case of the Uno is a 10 bit ADC (2^10 = 1024). Do any of the official boards have a…
asheeshr
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Logging small capacitance

I'm measuring capacitance of a system using a multimeter, and found that the value is very small (fluctuate from 50pF to 100 pF). The system is dynamic so the capacitance changes over time. Now I need to log this value to some text file (csv for…
Dzung Nguyen
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Increasing ADC resolution

At this moment I am using oversampling to increase my analogread resolution. This in combination with increasing the frequency of the ADC. Is someone able to take a look at it? #define FASTADC 1 // defines for setting and clearing register…
KoenR
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How to reduce AnalogRead noise?

Currently trying to read off values from a photodiode through analogread. It's constantly so noisy and I thought it might be something wrong with my low-pass filter, but I decided to just connect a 1.5V battery to an analog pin and had just as much…
Yousuf
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error: 'analogRead' was not declared in this scope

I am using Codeblocks with arduino IDE to simulate the control of a stepper motor, and the errors "'analogRead' was not declared in this scope" and "'A0' was not declared in this scope" keep popping. The code follows: #include const int…
Arthur Fagundes
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Reading analog signal from digital pin #6

Is it possible to use digital pin 6 (PD6_PCINT22/AIN0) to read an analog voltage with analogRead()? According to the ATMega datasheet, this should be possible. If yes how is it done ? (pin configuration)
Tristan Heitzinger
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Accuracy reading two analog inputs on Arduino

I need a help with this question. I'm trying to make a Wheatstone Bridge with Arduino, the main idea is read the two legs of the circuit with two analog inputs of Arduino, for the while I'm analyzing the values with 4 equal resistors as the Arduino…
Ivanks
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consecutive analogRead()

Has anyone noticed that if calling analogRead() in a consecutive way that the value drops by a bit as opposed to just doing a single read? And is this to be expected? I am using a Seeeduino XIAO.
MeSo2
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unexpected change of ADC value with multiple voltage dividers (thermistors and pot)

So this is my basic circuit. Three voltage dividers: one 10k pot, 2 thermistors. Fan driver circuit using TIP120 (currently just driving an LED from the 3.3v source). Board is a Leonardo clone, circuits.io only had the Uno in their library. Edit:…
twardnw
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Increasing analogread speed on the Arduino Uno

I want to transfer data from my smartphon to the Arduino by using the audio jack of my smartphone. For this I need verry high reading frequencys. I have used bitClear(ADCSRA,ADPS0); bitSet(ADCSRA,ADPS1); bitClear(ADCSRA,ADPS2); to boost…
gorilla
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Analog Read dummy file

Can we use just a analog Read without storing it i hear it it a good practice to take two reads for better accuracy example: // Read extra analog inputs for (int i = 0; i < 8; i++) { // Read analog pin to nothing. analogRead(i]); //…
Eric V
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Electret microphone board strange offset using Arduino

I'm experimenting with an electret microphone, specifically this one. I put it on my scope and I see what I expect - a really small voltage, typically under 20mV, that varies appropriately with sound. However, when I put it into my Arduino…
Michael Stachowsky
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How to read analog pins from a second Arduino

I've run out of analog pins on Arduino Uno and don't have time to order new parts. I've heard you can connect two Arduinos and I have access to another UNO. If I did that, could I read the analog pins of the second Uno on the first one? I'm planning…
user54636
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Getting the highest value from analog reading?

I am doing a project using an FSR (Force Sensitive Resistor), I'm currently reading values with no problem every 100milis. I want to output via Serial.print the highest value, I've read. I am having a hard time doing so. The project is use to…
ALEZA
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