Arduino Stack Exchange
Arduino Stack Exchange

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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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 an LED from GPIO 12, I would assign GPIO: const int…
acpilot
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Measuring li-ion that arduino is running from

I am using a 5v Arduino pro mini (with regulator and power led removed). I have been reading how to accurately measure Li-ion batteries when powering from the same battery you are trying to measure from. Using the 1.1V internal analog reference to…
Lindsay Cox
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How to know positive and negative in breadboard

I have this breadboard, and there is no indication on it about what is positive/negative on it. In comparison, this other breadboard (pic from the internet) DOES have indications: Can anyone give me a hint ?
N Sharma
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Why is my Analog Input channel adding voltage to my signal?

EDIT: Here are the links to the sensor spec sheet (http://www.omega.com/temperature/pdf/HX71.pdf) and manual (http://www.omega.com/Manuals/manualpdf/M4543.pdf) for your reference. I'm using a relative humidity (RH) sensor with an Arduino Mega. The…
L. Paw
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How to create a smooth change in voltage?

We are given two voltages A and B between 0 and 5V. So how do I generate a smooth/continuous analog change in voltage from A to B in a predefined time? The current with that varying voltage is 1 ma or less. The output voltage value is described by…
Pete
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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 electric fence used to prevent farm animals from…
TeD van Loon
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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 Low Voltage, Except XTAL1 and Reset pin Min:…
Tom Hale
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Measuring voltage from -12 to +12 VDC

I'm making a -12 to +12V DC regulated power supply, on which I want to measure voltage and current with Arduino (through a voltage divider, of course). I'm not sure, how to either detect nor measure negative voltage. I could "detect" it via a…
Jakey
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One LED in 4x4 matrix does not turn on

I'm an art student and absolute beginner to electronics/code - my broader goal is to learn how to control individual LEDs when there are many of them (like 64 or more even, so am learning about shift registers, multiplexing etc. also). I have been…
Miso
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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 ?
Jacques
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Programmatically-adjustable buck converter module?

LM2596 is easy to use and cheap, but I have to adjust the output voltage using a screw driver. On the web, there was a "hack" that someone posted, but that hack does not seem as clean or stable as using LM2596 as it is intended to be used, using…
Damn Vegetables
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Arduino changing output based on wire voltage

I’m new to arduino and I want to build myself smart switch that can be turned of both manualy and via wifi, is there any way to change position of relay based on if another wire is live or not? Im from europe so we have 230V outlets. Thanks for the…
krystof18
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Do the I/O pins on Arduino read current or voltage?

So I've recently started Arduino and I just had a question about the digitalRead() function. Does the IO Pins read Voltage or Current? The reason I'm asking is because of the attached circuit. So IO pin 7 is HIGH when the button is not pressed…
JamesM
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Is it possible to have long wire connections from an NodeMCU to a servo motor or button?

For my proyect, I need to conect my NodeMCU to a servo motor as well as a push button, the thing is, the distance from the NodeMCU and both components has to have a distance of around 6.10 meters (or 20.0131 feet), I dont know if it is possible to…
Marcelo_M
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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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