Questions tagged [current]

Use this tag to refer to the volume of electricity traveling through any given wire at any given time. It is measured in amps.

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15
votes
2answers
31k views

Is there a limit on how much current a pin can sink?

I've been experimenting with an 8x8 LED matrix controlled by an Arduino Uno. As I think is typical, the matrix uses a common anode for each row, and a common cathode for each column. At the moment, ...
9
votes
1answer
26k views

A digital I/O pin as ground

I want an I/O pin to return current in a circuit, similarly to the function of ground. Which of these will achieve what I require? pinMode(pinnumber, OUTPUT) digitalWrite(pinnumber, LOW) or ...
5
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2answers
1k views

Arduino potentiometer example: what limits the current?

I have a question regarding potentiometer example: https://www.arduino.cc/en/Tutorial/AnalogReadSerial If I turn the potentiometer to the marginal position and have 5V at A0 (and almost zero ...
5
votes
1answer
4k views

ArduinoMEGA: 64 digital inputs cause random digitalRead values

I have 64 hall effect sensors (magnetic field sensors) (DRV5023AJQLPG) connected to an Arduino MEGA 2560. For that, I use 48 digital pins and 16 analog pins as digital input pins. The program in the ...
4
votes
3answers
51k views

Powering up LED strip - How many amps?

I want my Arduino to drive a LED strip. The LED strip in particular is the 3528 non-waterproof type. To power this up, I need a 12V power supply. My LED strip is going to be 5 meters. Now my ...
4
votes
1answer
22k views

Will 5V 2A current input to the power port kill my Arduino? [duplicate]

I want to power my Arduino with a mobile charger, the out put is 5V 2A, will it kill my Arduino? And what's the max input current as power source?
4
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1answer
1k views

PWM signaling with Arduinos: What is the reason for the ground connection?

This may sound like a very dumb question and I apologise in advance. I've gone through reading about PWM and working on some example sketches to control PC fan speeds using PWM and Arduino. In all ...
4
votes
1answer
742 views

Which device to use to measure AC current using Arduino?

I'm building a home automation product and want to measure AC current using Arduino (as of now). I've used ACS712 5A Hall Effect Current module but there's a lot of electrical noise and also the ...
4
votes
1answer
232 views

Methods to prevent Accelerometer values changing from current spikes

I've connected an Arduino Uno to a MAX7219 IC, which is connected to only one standard 8x8 LED matrix, and an ADXL355 3-axis accelerometer. I use the matrix initially, and turn on all LEDs, while ...
3
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2answers
6k views

Arduino Power - DC adapter

I have a 12V 2.5 ampere Dc adapter.Can i use it to power arduino uno board? It says on the arduino website that i can use 9-12V and upto 1 ampere. I am concerned with current limit here..
3
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2answers
20k views

Max current of Vin and 5V pin on Arduino Nano

What is the max current of the Arduino Nano's Vin (30) and 5V (27) pins?
3
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1answer
446 views

What is the Maximum Current an Arduino can Supply?

I was wondering how much my Arduino I/O pin can output when it is set at Output and is at High. I am using an Arduino Uno R3. Thanks in Advanced.
3
votes
1answer
4k views

Do I need to use a resistor if I am using a potentiometer to control an LED's brightness?

I am currently tinkering with an arduino, and am using a potentiometer to change the brightness of an LED. I understand that usually, a resistor is added to the circuit to limit the current flowing ...
3
votes
1answer
555 views

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 ...
3
votes
1answer
62 views

What is the maximum “wattage” can be pushed into an ATMega328 ADC pins?

I was doing some Ohm's Law calculations to calculate the voltage output from a 2-resistor voltage divider, the input will be with a maximum of 12 volts, I want the ATMega328 to measure that voltage, ...
3
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2answers
553 views

7805 powered Atmega328 Stops working when input of 7805 exceeds 7volts

I am developing a circuit with atmega328, the MCU is powered by a LM7805. The input of 7805 is given by a variable supply. Till the input of 7805 is 7volts, the output voltage is 4.9volts and current ...
3
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2answers
199 views

Arduino Uno VIN 2A

Trying to get started with the Arduino, so I'm trying to do something kinda simple. I'm following this tutorial: Build Your Own Dynamic Ambient Lighting For A Media Center However, I'm still confused ...
2
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2answers
1k views

Attiny85 appears to be drawing 0.2mA current but battery running down more quickly

I am trying to get a temperature sensor (tmp36) working with an Attiny and if possible I would like it to run for several weeks. I have tried to power down the Attiny and it appears to be drawing only ...
2
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2answers
329 views

Does the square-wave nature of PWM dictate how much resistance you need?

I think the answer is yes, but I wanted to ask the question anyway for future common reference. And to check my understanding. Say I want to power 10 LEDs with PWM with my Mega 2560. I have a bunch ...
2
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2answers
149 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 ...
2
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2answers
2k views

Circuit doesn't work when multimeter/current meter is attached

I'm working on a battery-powered data logger, using a bare Atmega 328. I'm using sleep between sensor readings, via the Narcoleptic library. Everything seems to work fine, until I connect my ...
2
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3answers
3k views

Arduino Pro Mini maximal and recommended current per pin

In Arduino Pro Mini (3.3V) specs indicated the maximal and recommended current per pin, 40mA and 20mA respectively. Does these values means input current (i.e. safe input current Arduino can handle) ...
2
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2answers
4k views

Can I share the VCC (5V) on my Arduino Pro mini with multiple modules?

Right now I am onto a new project where I am building an obstacle avoiding landrobot. I use an arduino pro mini as my board and I have a few hc-sr04 sensors here at home. The problem I have right now ...
2
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4answers
1k views

Power suply for MicroSD card breakout board

I'm developing a project and I need to connect to my Arduino Mini with a SD card breakout board. The problem is that I can't plug it directly to the Arduino since it is already powering some sensors ...
2
votes
1answer
2k views

What happens if I draw too much current from ATMEGA IO pin?

I revisited an older device that I made and discovered, that I had an 8 Ohm speaker connected directly to ground and an IO pin of an Atmega328P. According to my calculation that means that the pin ...
2
votes
1answer
409 views

Using Arduino Micro With 12V Buzzer

I have an interesting situation. I wonder if anyone can help? I have: 4x Arduino Micros loaded with the basic Blink sketch 5x 12 volt buzzers A desk full of completely fresh Duracell AA and 9v ...
2
votes
1answer
1k views

What's Leonardo 5V pin current limit?

I'd like to know how much current can supply the 5V pin and the 3.3V pin on an Arduino Leonardo board. I've been lead not to trust the specs on Arduino's website. And, as an added question, can the 5V ...
2
votes
1answer
876 views

“tamper” circuit of a reed switch: can I connect the two wires to an INPUT and an OUTPUT pin?

While working for the automation side of my new house, I'm currently in the process of installing several reed switches on top of external doors and windows. Even if this could be used as a "...
2
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2answers
6k views

ATMega I/O maximum current

According to the ATmega328P datasheet, the total current from all I/O pins must not exceed 200mA. Let's say that an Output pin sources 30mA and an Input pin sinks 10mA. The total current should be ...
2
votes
1answer
34 views

WS2812B Power Supply

I have a WS2812b addressable RGB led ribbon that is 5m (150 RGB leds). I purchased a 5v 10amp power supply to power it; however, whenever I try to use it to power the LED strip the leds start flashing ...
2
votes
2answers
77 views

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 ...
2
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1answer
220 views

How to calculate voltage?

I want to check each cell voltage using arduino. and how to calculate dc current using CT Sensor using Arduino?
2
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1answer
65 views

What is the Proper Voltage to supply an enough Current to the Arduino

I'm just confused about the supply that I should use in driving my arduino. Is it okay to use a 3.7V with a 1000mAh to supply it? I will be using a Lilypad Arduino. Your replies would be a big help ...
2
votes
2answers
325 views

Deviation of power consumption between datasheet and real world?

According to the Atmega328P-PU Datasheet (side: 589) the current consumption of the microcontroller should be around 9.5mA (at 16MHz and 5V). But I measured 15mA. (Nick Gammon who did some pretty good ...
2
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2answers
372 views

Can I use relays with 10A125V~ for my 220V~ applications, safely?

I am using the TinkerKit Relay Module and recently they changed the relay mounted on the board from a white one with 10A250V~ to a black one with 10A125V~. In my country the voltage is 220V~. Can I ...
2
votes
1answer
390 views

Discrete H-Bridge very low current output

I have built two parallel H-bridges from "Design 1" on this page as you can see in the attached schematic. However when I apply the external power (VCC1 in the center of the diagram) the two motors ...
2
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0answers
24 views

Selection of External CT for my application

Here I have attached my ckt for my application. My application is Motor protection Relay. Based on Current sense of 3 CT tripping of relay will occur. Tripping might due to under/over/SC/Locked rotor ...
1
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3answers
560 views

The importance of I/O pin DC current

I am thinking about buying Arduino or Raspberry Pi. I generally know Arduino advantages (fast start-up, low consumption, ADC converters) and disadvantages (low memory, low connectivity, hard ...
1
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2answers
90 views

Maximum Current?

This is an extremely noobie question, but I have a 5V at 2A power source. This power source is going to be powering 6 Sharp IR distance sensors(20-150cm) and a few other low current consumption ...
1
vote
2answers
769 views

Can I measure the current (mA) of my project with just a multi meter?

I have a project and wish to choose the correct battery back for it such that it will last the required amount of time between each recharge of the battery pack. I am using an Arduino Duemilanove with ...
1
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2answers
150 views

May arduino hang when current is changing over time?

As in title. I've got quadrocopter where Li-Po is parallely connected to motors as well as to arduino. May current driftage cause arduino hangs ?
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2answers
547 views

Voltage and Current and Arduino

I put a LED into 3.3V of the arduino and Ground, and it blew my LED violently, smoke was everyone, the whole half top of the led blew up across my room. However, when i program the arduino with Pin13 ...
1
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1answer
276 views

How to reduce current from a AC TO DC power supply for arduino use

I have a AC to DC converter that was originally used for recharging the PSP, I stripped the 2 wires of the output and was wanting to use it for my arduino instead of using a 9V battery, it's output is ...
1
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1answer
8k views

ACS712 sensor reading for AC current

I'm trying to track down a clearly/simply articulated piece of code to take a reading from the ACS712 current sensor (link to download PDF data sheet). I understand that these sensors are noisy, and ...
1
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2answers
85 views

How do I provide a negative current?

I'm trying to use an ATMega328 board to control a board of a broken UPS device. I replaced all the internals of the UPS by custom components, so the only things which remain are the chassis and the ...
1
vote
1answer
2k views

Understanding flow of current with pull-up and pull-down circuits

I am new to all of this and was trying to figure out what was happening with pull-up/pull-down circuits. I think I understand what happens when the board handles the pull-up/pull-down but I wanted to ...
1
vote
1answer
475 views

How can I power an Arduino in a 3-phase environment?

I am working on a project which uses an Arduino board. Currently I am testing my device using 2-phase power and it works fine. I want to use that device in agriculture fields where 3-phase power is ...
1
vote
1answer
665 views

How to choose between Lithium-ion vs NiMH batteries to power Arduino on the go.

For my next project I'd like to use a battery pack to power my Arduino. I would also like to get a small solar panel and charging module to charge these batteries when possible (during the day). What ...
1
vote
1answer
104 views

Measuring resistance conceptually and in code?

How would I measure resistance over a certain length? In this case the resistance is variable. What I have in my head is that you would output a certain amount of current from one pin, and measure ...
1
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2answers
155 views

Measuring current directly with Arduino

Is it safe to measure current like this as long as measured voltage drop don't exceed 5V? I'm asking this because in almost all current sense circuits they used an opamp in their design. Do I need a ...