Questions tagged [analogread]

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

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Measured voltage higher than AREF

What happen when a voltage measured by analogRead() is higher than AREF voltage? Example: AREF = 2.5V AO = 3.2V What is the maximum voltage ?
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Bootstrap circuit for electromagnet drive or sense? [migrated]

Is there a bootstrap circuit or H-bridge design so that a coil can be energized in one mode (e.g. with an NPN transistor and flyback diode), or sense a changing external magnetic field in another mode ...
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DFRobot V2 sensor doesn't change when setting a wet paper on fire

I tried the DFRobot V2 sensor with an MQ-7B on my Arduino but strangely when I set fire to a thing in my sink the gas sensor doesn't change: Indeed I get more or less: temperature = 404 gas = 919 ...
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Double Click for Analog Sensor with Threshold

I am trying to build a keyboard for MD patients. I have only five force sensors, each sensor encodes 4 letters (20 in total), which means I am missing 6 letters. I thoght of using double-cick, for ...
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1 vote
2 answers
78 views

Why analogRead's value decreases when I decrease the value of resistor?(I use digitalWrite(high) to positive terminal of resistor)

Basically, my circuit contains only 1 resistor(like the basic LED circuit). I tried to know what is the actual voltage of digitalWrite(High). I don't understand why the value of analogRead does not ...
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1 answer
69 views

Why do I get different times when using analogRead() inside while loop?

I have the following code which checks the latency of another board. int triggerPin = 13; int dataPin = 9; int ejectorPin = A0; unsigned long t_start = 0; unsigned long t_end = 0; ...
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NodeMCU dev board shows 13 for ADC when grounded - why?

I have a NodeMCU 1.0 ESP-12E development board. Trying to hook up a LM35 to measure temperature. For that I need to use the analog pin A0. However it seems my sensor is out by about 4C. I traced ...
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Analog UV sensor displaying incorrect values in serial monitor (GUVA-S12SD)

Using Arduino Uno and a GUVA-S12SD sensor (https://www.adafruit.com/product/1918). Here's my circuit. 5V into sensor+, GND into sensor-, A0 to sensor out. Here's my code: void setup() { Serial....
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2 answers
66 views

LCD TFT 2.4"" changes the values of analog read of Arduino Mega

I have a Arduino Mega with LCD TFT 2.4"" with reading 5v signal on A8 pin (Arduino mega pin) from a raspberry pi (just to test). They are grounded together. When the Arduino is without the ...
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1 vote
0 answers
75 views

I'm getting really unstable analog values with my B103348 joystick

I'm trying to make my B103348 joystick control a DC motor but I'm getting very unstable values from it specifically when the y axis is at 0. This is what my Serial monitor shows... 0, 21, 21, 21, 0, ...
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2 votes
1 answer
91 views

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.
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Arduino Multiplexer Input voltage per pin not decoupled

I am very new to electronics (software engineer background). I want to send an analog signal (5V) to one/many input wires. The input wires are connected to a 16 channel mutiplexer. My arduino then ...
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3 votes
1 answer
185 views

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....
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0 votes
1 answer
505 views

Analog read not working while using WiFi

I have an ESP32, the current program running on it uses WiFi but, if I use WiFi and Analog read at the same time, Analog read does not work. Why does this happen and what's the way around it? Hardware ...
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3 answers
265 views

Can I test if something is connected to analog pin?

In my sketch I have a potentiometer connected to A0. The value of the pot is used to adjust the speed of a connected item. I have set the speed to have a default value, but doing analogRead() on a ...
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Pyfirmata util.Iterator causes serial communications issues with more than one Arduino

I'm using two Arduino Megas in a project to read data from a bunch of analog sensors and then output PWMs on digital pins according to their value. These analog signals are also being plotted on a ...
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1 vote
1 answer
398 views

Potentiometer only display analog voltage value of 1023 in proteus

I connected arduino uno with lcd and potentiometer to display the analog value (this is the basic of my project). However the value displayed on the lcd remain 1023 eventhough i have vary the ...
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1 vote
0 answers
97 views

Problem with floating of AnalogRead

For a university Lab course i have to realize a UPS unit with a internal LiPo battery . The unit uses as battery charger a buck converter I have only a problem with the battery charger (buck converter)...
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1 vote
0 answers
29 views

Math on analog read wrong result

I'm trying to execute a math of analog read but I get some weird result.. I searched about int and floats but didn't understand.. My code is : #include <SevSeg.h> SevSeg sevSeg; int bitsChange ...
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3 answers
169 views

Inaccurate voltage readings on an esp32 as opposed to multimeter

I am working on detecting the amplitude of a signal coming from a guitar pickup. I am using an esp32 and an LM386 module for amplifying the signal. I get quite stable readings with a multimeter, but ...
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0 votes
1 answer
74 views

Check pin capabilities at compile time

Are there board-independent functions to check pin capabilities at compile time? I.e. Can the pin be used as output, as in digitalWrite()? Does the pin support PWM, as in analogWrite()? Does the pin ...
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2 answers
42 views

Is defining a function improves speed rather computing average for each analog input separately

My Arduino controller reads data coming from four different sensors. After the data is read, I individually compute four input average values. I understood that I am having the same lines of code ...
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1 answer
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Why AnalogRead shows value (395) when its on HIGH State ? why not shows 1023 when its high State

I Took a output from ESP8266 and Connected it with Arduino Nano Analog input A0 i use BLYNK app to on/off D0 pin in ESP8266 , and i connected ESP8266 D0 pin with Arduino Nano A0 analogPin. when ...
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1 vote
0 answers
27 views

ESP32 reading analog 2.4Ghz

Is there a possibility to analog read on the 2.4Ghz band to just read how much activity is in the presence of your device? Not parsing the messages but just listening to how strong of a signal you are ...
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1 answer
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SEN0114 moisture sensor low max reading?

I am using the following SEN0114 moisture sensor with an ESP32: https://datasheetspdf.com/datasheet/SEN0114.html How come when submerged in water I only get a reading of ~2500? Should this not read ~...
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1 answer
173 views

analogRead() doesn't read more than 500Hz

I connected a wave generator to the analog pins to read the frequencies of the waves generated. I used different frequencies of sine waves with a minimum of 0V and maximum of 5V. Whenever the voltage ...
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3 votes
2 answers
269 views

Arduino measuring high-voltage electric fence

I would like to know if someone has experience with measuring high voltages using an Arduino. I know you can use resistors to lower the voltage, however. I want to be able to measure the pulses of an ...
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1 vote
1 answer
127 views

Time signal. Determine the presence of pulses and their duration [closed]

I want to detect the exact time signal from an FM radio station. The signal is transmitted in the form of 5 short pulses and one long one. My task is to determine the presence of a pulse in the audio ...
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0 votes
1 answer
93 views

Attiny : Is it possible to analog read on PB1?

I'm trying to read an analog input on the Attiny85 physical pin 6 (PB1, PWM), but analogRead(PB1) always returns 1023. Is it even possible to use analogRead on this pin? I'm fairly new to this so ...
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1 vote
0 answers
48 views

Phantom reading

my project is to control led diode and dc motor, test shield buttons, and check system run time. Testing buttons and run time i have done. Deal is with led and dc motor control. I'm getting phantom ...
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1 answer
868 views

How to read an analog value on ESP32-CAM with the SD card reader enabled?

I use an ESP32-Cam module for a project for which I need both the SD card and the cam. According to this page, the only pins that are not in use by either the camera or the SD card reader are GPIO0, ...
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1 vote
1 answer
28 views

always detects same pin as HIGH even when its not connected

Im practicing with an arduino UNO board (I'm a begginer) and I'm trying to turn some LED's on depending on which analog pin is connected to 5V. Here's my code: int statusLed = 11; int out1 = 2; int ...
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0 answers
39 views

Does anybodyknow how to program Muscle Sensors v3?

#include <Servo.h> const int x = 200 //Naming the servosServo Servo servo1; Servo servo2; Servo servo3; Servo servo4; Servo servo5; Servo servo6; void setup() { Serial.begin(9600); ...
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4 votes
6 answers
2k views

What is the most efficient voltage divider for Arduino?

I need to make voltage divider, so I could read a battery voltage up to 14.4 V. Could I use very high resistance resistors for that, so the current would be very low (to not to discharge battery)? On ...
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1 vote
1 answer
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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++) { // ...
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1 answer
129 views

Noise in Analog Read Serial from an instrumentation amplifier(ina122p)

I am trying to read the values from a simple EMG circuit (with an INA122P) using the analogRead() and plotting in the plotter using an Arduino nano v3. I am powering the ina1222p from the 5v pin of ...
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2 votes
0 answers
73 views

Reliably using analogRead as a compact digitalRead

My goal is to reduce pins being used for micro-controllers with limited pins, or projects requiring a few different digital input values. How I intend to do so is by using ADC pins to gather four ...
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2 votes
1 answer
145 views

The analog read is not giving the correct waveform as that of an oscilloscope

I have this code that fetches analog input values from terminals A0, A1 and A2 of Arduino mega 2560. But, when I plot the data, it does not give the desired waveform. The desired waveform is parallel ...
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1 vote
0 answers
35 views

Connect k-type termocouple using o-amp

first of all I have to say that this is my first Arduino thing. I'm trying to connect a k-type termocouple to my Arduino using an LM2904 Oamp, Yes I know that this is not the best solution but is the ...
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2 votes
2 answers
130 views

printing the analogRead() functions result crashes Arduino

I have created a curcuit which reads the analog pin 3 auf the arduino nano and does other things dependant on the returned value. However I have problems regarding the analogRead() function. Whenever ...
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1 answer
163 views

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 ...
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1 vote
1 answer
252 views

Nano: All digital pins do not output anything

New user here. Using the examples provided on the Arduino IDE software I could produce melodies with a piezo buzzer, or have a blinking LED. Not anymore. No digital pin is giving anything. I can see ...
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0 votes
1 answer
115 views

How does supply voltage affect `analogRead()` on AVR-based microcontrollers?

I'm using an ATmega328P based Arduino to prototype reading a TMP36 temperature sensor. I will eventually move this to an ATtiny85 based board with a battery supply. Both the TMP36 and ATtiny85 have a ...
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0 votes
0 answers
263 views

eps32 bad adc even with external adc (ADS1115)

Im trying to read an analog value with my esp32 and send it over wifi to another esp32. The wifi part works flawless, however when i try to read an analog value form the esp32 its not useable. It ...
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1 vote
1 answer
124 views

ADC value changing after changing Timer1 value in program

I'm writing a code where analogRead() reads ADC value from load. After reading ADC value, if it is not in range, I need to manipulate Timer1 value. Which is also getting changed. But, after changing ...
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0 votes
2 answers
879 views

Using SDA and SCL with analog inputs at the same time

I'm trying to build a robot arm based on Arduino UNO and PCA9685 controlled by few potentiometers. The easiest way that I figure out and find on internet is using two Arduino's, one as master and ...
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1 vote
1 answer
67 views

Data type explanation regarding analogRead of a photoresistor

This is a fundamental question - very new (1st post) and trying to learn. I have a photocell connected in series with a 10kOhm resistor between 5v & Gnd (to make a voltage divider) and the ...
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1 vote
2 answers
181 views

Why does the LEDs affect Analog Input?

So I'm working for a project to control RGB Led Strip using microphone or sound sensor with Arduino Nano. I'm using 5050 RGB Led Strip around 120 LEDs, and I control them using simple transistor ...
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107 views

How to calibrate Arduino DUE analog readings?

I am having a problem with the analog readings on my Due. On pin A4 and A5 I am measuring voltages: double vcc = 3.288 // taken on pin 75 (ADVREF) ; analogReadResolution(12); result = analogRead(A4) ...
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1 answer
2k views

DHT11 analog or digital?

I saw some projects with DHT11, some connect it with analog pin, others connect with digital pin. Is there any difference / advantage connecting to the analog?
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