Questions tagged [voltage]

Voltage is the difference in electric potential between two points of an electric circuit, measured in Volts (V). Voltage can be constant (DC) or varying (AC).

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Why voltage drop cause changes in analog reading of hall-effect sensor?

The sensor is a hall-effect UGN3503 sensor and I'm using a TL431 shunt regulator as voltage reference for analog readings. I'm using analogRead() with setting the analog reference to external ...
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1answer
26 views

3.3v pin on a 5v Pro Micro?

I have a arduino pro micro that runs on 5v. I also have a Max4466 that needs 3.3v, however the pro micro doesn't seem to have a 3.3v VCC. Is there any way to attach the max4466 to the Board?
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2answers
184 views

measure +3V and -3V through resistor divider and switch on/off by digital pins

I've seen that resistor dividers can be used to read negative voltages, but I'ld like if there is a way to accomplish this with less components and having a way to turn this off. I was thinking if ...
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67 views

Handling arduino output current

I need to power an actuator that requires 12 volts and consumes between 5 and 10 amperes depending on the weight it is charging. Therefore I bought a power supply of 12 volts and 10 amperes. My ...
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1answer
21 views

analogRead Function AC Voltage Reading Capabilities

Usually when you sense AC voltage, you get a sinusoidal waveform. However, for AC voltage sources, Arduino analogRead ( ) only presents positive voltage values. So what's basically happening? Is it ...
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49 views

AC Voltage Sensing using Arduino Uno

Is it possible to sense AC Voltage using analog input for Arduino Uno or can it only read DC? I mean I've tried connecting an AC voltage source to analog and I'm reading some numbers. However, I don'...
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2answers
36 views

Load Resistor Use for Voltage Sensing by Arduino

I connected a piezoelectric film to a Arduino Uno board via analog input. However, as I was getting very high voltage values (reaching 5 volts without much movement). Therefore, I added a 1 megaohm ...
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1answer
32 views

Maximum power rating for Arduino UNO revision 2 (SMD)

I have located the 5V voltage regulator chip on my Arduino board which I am hoping to use to power an attached device (which draws up to 500 mA at 5V). The chip is next to the plug for the external ...
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50 views

Low voltage security

I'm building a circuit with a GPS sensor and an esp32. My input voltage is designed to be 5V but I experienced some issues where people put lower charger in input (<4V). As a result my esp32 will ...
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1answer
151 views

How to connect L298N motor driver to 5v input supply? [closed]

I'm trying to connect 5v supply to a L298N motor driver at it's 12V-35V input pin but it's not working. If I'm connecting to 7.2V supply it's working. Is there any way to connect 5v supply? I want a ...
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32 views

Some noob questions regarding Arduino Nano based drones [closed]

Foreword: I am doing my Bachelors in Aerospace Engineering and part of the requirements to graduate (and get a good grade) is that I must complete 3 projects of my choice, and it must be unique. So in ...
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207 views

Generate a ramp input with an Arduino Uno

Is there anyway to generate a ramp input from an Arduino Uno? A visual depiction of the pulse I am looking for is as follows: With other microcontrollers, I was able to use their in-built DACs, ...
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33 views

How to measure multiple voltages (Thermocoupes)

How would one measure many (20-100) small voltages in the 0-80mV range with an Arduino? I will need to amplify them and put them into the ADC. But i also need to switch between them. I want to ...
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1answer
28 views

How do I supply either (1) dual voltage or (2) negative voltage? [closed]

Sorry in advance if this question already exists--I tried to search but my keyword knowledge is shaky. I have created a Colpitts oscillator on breadboard using AA batteries as the power supplies. I ...
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0answers
129 views

Measuring battery voltage [closed]

I am trying to use this way to measure my battery voltage at least approximately, but I am getting weird results. I am running breadboard atmega328p with internal 8 MHz and powering it from a LiPo ...
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42 views

Making a voltmeter for PV system over 60 VDC

I'm trying to make a voltmeter for my PV system that can range from 24 VC to 120 VDC. I'm aware of the fact that we have Arduino modules available that can work for 25 VDC system. However in my case ...
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1answer
154 views

Digital I/O threshold voltages for ATmega32u4

What are the voltages on a ATmega32u4 (eg Arduino Leonardo) such that a HIGH or LOW is read? I want to ensure that I'm reading the chip reference manual correctly, where Table 29-1 says: VIL: Input ...
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1answer
265 views

Can I power a Wemos D1 R2 via the VIN and GND pins?

Can I power a Wemos D1 R2 via the VIN and GND pins? If so, at what voltage?
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1answer
220 views

Voltage sensor Calibration

We had used a voltage sensor unit to measure the voltage of the odroid board using an Arduino Uno. wWhen I uploaded the sketch and got the output, the value which was being displayed was around 4.7 to ...
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1answer
209 views

Detect power interruption on NodeMCU

Im using a 5v 1A power supply and connected to VIN pin on the NodeMCU. I also use 18650 battery to keep NodeMCU running in case the power supply shuts off due to power interruption. I'm planning to ...
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0answers
69 views

Transistors to use for eight voltage sweeps from two PWM Arduino pins

On my Arduino Mega, there are two PWM pins open. There are eight analog voltage inputs to a datalogger. They are connected through a PCB, and I need test them with a DC voltage sweep. (There are many ...
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1answer
26 views

How to build an µC controlled power regulator?

The idea: Use an Arduino-like µC to control a set of CPU fans by control the voltage the CPU fans receive. My question: How can I do this in an easy way? Yes, I know, there is PWM but this is not ...
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2answers
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Arduino UNO socket

As I learnt so far is that Arduino UNO board has a socket for power input. The available power input range is between 7V - 20V, but the optimal usage range is 7V-12V. Here I am wondering: ---> if ...
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2answers
883 views

Difference between 3.3v & 5v

Im quite new to arduino in general and i'm sorry for the beginner question. could someone explain what the 3.3v and 5v on boards do? I know their voltages. but can you run one on the other? whenever ...
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2answers
86 views

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

I have a signal that fluctuates between -70mV and 50mV. How would I get the arduino to read this.. Ultimately I am trying to graph the data in real time so it looks like this. https://imgur.com/a/...
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1answer
37 views

Powering arduino and node mcu [closed]

I want to power up my Arduino and my Nodemcu via 12 V , 1 A power adapter (it's an AC to DC power Adapter). Recently I have two voltages regulators: a 5 V for nodemcu and 9 V for Arduino Uno. The ...
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1answer
219 views

Connecting 5V arduino logic with 12V car logic

I need to connect arduino to K-Line in my car's OBDII port. I used an L7805 to power the atmega but how can I interface 12V car logic with 5V arduino logic? The problem is, the connection has to be ...
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1answer
1k views

Read frequency of input in digital pins

This is a somewhat theoretical question: Let's say I have some sensor that sends digital signals to one of Arduino's digital ports. Now, I don't know the frequency it sends those signals in. For ...
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2answers
77 views

How to produce multiple DC voltages for a single project

So the title pretty much says it all, but for an example, I have an arduino board, 5-12 V, an LED bank 18 V, and an ultrasonic mister 24 V. I know some brute force methods to power ...
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1answer
33 views

Different voltage sources across Vin and DC jack

So I understand that the USB VBUS circuitry turns off provided there is a high enough vin voltage using the PFET and comparator. I can see that the DC jack is connected to the Vin pin via a diode. ...
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2answers
92 views

3.3V from 5.0v outlet

I am working with an Adafruit Feather 32u4 FONA board. I want to connect a GPS module I have worked with before (3.3V required) but am not having much luck. I have studied the pinout of the board and ...
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1answer
94 views

Why does reading an analog pin give a different results when interfacing with Processing?

I am interested in measuring the voltage over an analog pin (A6). When I use the Arduino IDE to print the results through the serial I get values around 300. Here's the code void setup(){ Serial....
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1answer
43 views

Using a DFRobot Voltage Divider

I'm reading on the DFRobot website to implement this Voltage divider: Analog Voltage Divider SKU: DFR0051 void setup() { Serial.begin(9600); } void loop() { float val; float temp; ...
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1answer
369 views

Arduino Nano off 9V : is there any change to output?

I'm building a test circuit on an Arduino Nano that consists of a simple 220 Ohm resistor and an LED on pin D2 which is routed back to GND (ground). It's as simple as this: It's running a very ...
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0answers
115 views

HC-05 3.3 voltage regulation

HC-05 Bluetooth RX requires 3.3 v (TX has a regulator built in) I understand my uno and nano are 5v Ive connected a 3.3v Zennor in series with a led and resistor and with multimeter established the ...
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2answers
77 views

Need Input: Wait for voltage input to begin script & when voltage maintains 0V for X amount of time Reset and wait for Voltage Input

So I'm currently working on an automotive set up. I'm using a 555 timer to emulate a turn-signal alternating voltage pulse (12V to 0V and repeat) for debugging purposes which is output to turnPin/A1. ...
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1answer
462 views

PC Fan Speed Control [closed]

I am working on a project to blow air gently through a number of pipes and variable speed. I would like to use a standard PC case fan and have control of whether the fans are on/off and also what ...
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2answers
31 views

Batteries and amps in parralel [closed]

So, i am about to buy a brushless motor a ESC and a 18650 batteries for my arduino. The batteries "specs" is 3.7v and 20a, if i would to put 2 and more in parallel would i get 7.4v 20a or 7.4v 40a? ...
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1answer
570 views

Will Nodemcu support 4AAA

Will Nodemcu support 4AAA batteries which is 6v approx, or should i go with 3AAA batteries which is 4.5V approx. And one more question , is it ok to use AA instead of AAA ?
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1answer
211 views

NodeMCU ESP12 Voltage

I'd like to power an NodeMCU off of four 1.5v batteries. That's 6v. Depending on the source I've read that 5.1v will fry the board and, just a few clicks later, that the board will take up to a 20v ...
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2answers
97 views

Controlling voltage and current from chip?

I'm well aware that this question perfectly showcases my spectacular ignorance, but oh well. It's a simple enough question, so here we go. I have a 595 chip (SN74HC595) wired up to an Arduino, fed by ...
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3answers
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NodeMCU - Vin pin as 5V output?

I know that Vin can be used to power the board but have also been reading that it can be used as a 5V output. Is it possible to assign Vin as an output as I would any other GPIO? If I want to power ...
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2answers
133 views

Max current per pin is 40 mA. But it is always 40 mA?

I need to calculate resistor for a PNP transistor. To do this I need to know the voltage and current. I know voltage is 5 volts as it is easy to find in the internet, but how about current? I mean ...
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1answer
97 views

Have I fried the voltage input on my Arduino Nano?

I tried using my Arduino Nano in a circuit, switched on power to the circuit and heard a crack and smelt a bit of burning - something shorted. I have plugged my Arduino into my PC with a USB, the ...
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1answer
49 views

Designing around Output pin limitations

I'm new to Arduino and am working on a project with my son. We are using the LillyPad USB board (schematic) to drive a bunch of LEDs (LED Datasheet). Our project is based loosely off of the 'Turn ...
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3answers
2k views

Combining code for multiple sensors (Current and Voltage Sensors) in one program

I need to operate 2 different sensors (Current and Voltage) simultaneously. I have managed to run each one of them separately and I don't know how to manipulate the code so they could work together. ...
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1answer
151 views

How can I make an AC analog voltage with Arduino?

I am trying to create an AC voltage in Arduino. Until now I have only managed to get a square wave. How can this be achieved with Arduino? If I try: int up; int down; int out = 11; void setup() { ...
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1answer
1k views

CH340 3.3v stability

I want to use the 3.3v on a cheap Arduino Nano clone as my ADC analog reference voltage. The 3.3v comes from a regulator inside the CH340 USB serial chip. I've measured the voltages (My DMM is NOT ...
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2answers
126 views

Smart way to map digital pins to a for loop over analogue pins

First post here and I have very little Arduino/c programming knowledge so forgive me my ignorance. I am processing 18650 cells for a little powerwall project. I am using an Arduino pro mini ...
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2answers
1k views

How does Arduino digital input pin measure its input voltage?

Just starting with my first Arduino project. In order to measure voltage in a circuit I connected my multimeter to two points in the circuit (for example before and after a resistor). I am interested ...