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Questions tagged [analogreference]

21 questions
13
votes
4 answers

Does ADC conversion to a voltage rely on the actual value of the +5 V pin?

Questions: Does the conversion of the ADC count to voltage depend on the actual voltage of the +5 V pin? If yes, what is the accepted method of getting that voltage from the board? Background/Detail: I have a circuit in which I have an Arduino…
Caribou
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3
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4 answers

what is arduino adc reference?

I'm using arduino for the first time and don't really understand what am I suppose to plug to the ADC refernce PIN... or if I even have to use it while plugging analog sensor to the arduino, thanks!
Eyal Givon
2
votes
1 answer

Nature of the voltage reference instability of internal 1.1V reference of ATmega328P (Nano)

The ATmega328P data sheet in table 29-11 on page 324 notes that the internal 1.1V reference (VBG) may vary between 1.0V and 1.2V. In this answer this is called "not stable or accurate". Question: Is this "unstable" or "inaccurate" or even both if I…
Harald
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2
votes
1 answer

Inaccurate and non-precise voltage reading from Arduino Analog pin

float get_volt() { rawVolt = analogRead(voltageSensor); vOUT = (rawVolt * 4.6) / 1024.0; vIN = vOUT / (R2/(R1+R2)); //if(vIN>12.0){vIN=12;} //if(vIN<11.12){vIN=11.12;} //return (vIN - 10.18) * (100 - 0) / (12.0 - 10.18) + 0; return…
Aditya Singh
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2
votes
1 answer

Vcc measurement with internal 1.1V reference fails on 3.3V powered Atmega328

I need to monitor a battery plugged to an ATmega running on standalone mode. I use the "ATmega on a breadboard (8 MHz internal clock)" bootloader. More info here When the ATmega is powered with 5V the sketch outputs good values : arround 5100…
feuille osier
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1
vote
1 answer

adc arduino using reference voltage to read stable/constant lithium battery voltage

I want to read my lithium battery voltage. I WANT TO CREATE A FUNCTION TO READ MY 3.7~4.2V,1200mAH BATTERY VOLTAGE THROUGH A MICROCONTROLLER (ARDUINO OR ATTINY44). THEN I WANT TO CALL THE CREATED BATTERY FUNCTION IN THE FORMULA TO READ PRECISE…
electro_nooobbbb
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1
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1 answer

Arduino , python , pyfirmata , standard firmata

Is there a way to change arduino analog reference to EXTERNAL IN PYTHON using pyfirmata or any other library ? Necessary Links : https://www.arduino.cc/reference/en/language/functions/analog-io/analogreference/ My sensor has a 3.3 volt operating…
Shahan hasan
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1
vote
1 answer

Extremely unstable analogRead() on Arduino Nano when powered from an external source

I'm doing a really simple project with an Arduino Nano and found a problem. The circuit is a simple temperature sensor and a tension read from an analog pin everything showed on a Nokia 5110 LCD. When the Nano is connected to the USB everything…
Roberto Aureli
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1
vote
1 answer

How to work with analog readings using RPi and Firmata?

For context: I'm working on a project where I need to use sensors to figure out the current state of the environment. This process is done using an Arduino UNO and a RPi. The easiest way that I found to perform communication between both boards is…
coelhudo
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1
vote
1 answer

Using Li-Poly battery to run UNO + Adafruit data logger

I want to power Arduino UNO+Adafruit data logger (https://www.adafruit.com/product/1141) with a 3.7V 2000mAh Li-Poly battery. I am providing an excitation voltage of 3V, through one of the digital pins and a potential divider arrangement, to a…
NRai
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1
vote
2 answers

Arduino protecting analog input with internal voltage reference

Usually a common way to protect an analog input consists on reducing voltage and current in the following way: Current limiting components, as Resistors or inductors and voltage limiting components as diodes, zener, tvs. In this case for components…
piertoni
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1
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2 answers

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

I guess its a dumb question but couldnt find anything about it online. I know its possible to supply the AREF pin with 3.3 V to increase the ADC resolution. For the project i am working on the analog voltage i will be reading will be between 0 and…
Firat.Berk.Cakar
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0
votes
0 answers

AREF calibration on MEGA board: Calling analogReference() causes instability in sensor readings

So I'm a bit at a loss. I'm trying to set up a suite of environmental sensors to run off of the breadboard, and input analog data to my Mega. I have a potentiometer hooked up to the 5v and ground pins of the Power Supply Module, with the output of…
Jacob
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0
votes
1 answer

analogReference(INTERNAL) configuration

I need some help because I did not understand the configuration analogReference(INTERNAL). I would measure the intensity of a Laser beam passing through a filter. This is the circuit I would implement, using the 3.3 V power supply: In order to rise…
Paolo Monza
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0
votes
2 answers

Is AREF a stable output Ref voltage with analogReference(INTERNAL)

I'm using an analog input on a NANO board to measure the midpoint between two photo resistive (Cadmium) cells, with the two outside ends tied to GND and a source voltage. Basically a simple voltage divider. So it almost wouldn't matter what…
Randy
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