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Questions tagged [pins]

"Pins" are like gateways between the Arduino code running on the chip and the components attached to Arduino. It can refer either to the physical connectors on the board, or it can refer to the pins defined in the code.

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Can any Arduino Due pin be used for PWM?

Arduino Due has 54 pins. It says that it has 12 PWM pins. I know it uses a more powerful chip than other Arduinos. Can the number of PWM be increased? Can any of its pin be used for PWM?
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0 votes
1 answer
926 views

Arduino analog pins not working

I am having a problem with pins of Arduino Uno. I have connected a LED to one of the analog pins (A0), and I want to light up the LED with different intensinty. int ledPin = A0; void setup() { // ...
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2 answers
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digitalRead not reading input pin of ESP8266-01

I am trying to use a on-off switch with the ESP8266 to change whether GPI02 is HIGH or LOW. I am using GPIO3 as input. My circuit looks like this: The red area to the right is a relay, I wasn't sure ...
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  • 163
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2 answers
323 views

Arduino mega board 5v pin does not gives 5v when 7.5v is applied through external source

I gave 7.5v to the arduino mega board through battery. 5v pin in the board gives me the same voltage as input. Earlier it was working fine now it is giving problem.Please let me know the solution as ...
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2 votes
0 answers
193 views

Unable to send IR command

I am trying to switch the TV on using Arduino. Following is my set of code #include <IRremote.h> IRrecv receiver(2); IRsend sender; decode_results results; long repeatitions; long count; ...
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1 vote
2 answers
394 views

How to connect a simple wall switch to arduino GPIO

I am trying to create a smart doorbell, but my problem is that doorbell makes ring any time when nobody touch the button. I think that the problem is caused for the incorrect way to connect the ...
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0 votes
2 answers
2k views

Arduino Uno simple LED example with pointers

I am new to Arduino and I have recently started off by trying to turn on an LED connected to pin 13 on my Arduino Uno using pointers. I opted to do this with pointers because this would give me a ...
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1 answer
281 views

PWM on Pin 4 - arduino Micro

I am using Arduino Micro. Is there any way to use PWM on pin 4 instead of Pin3 ? I tried to change pins_Arduino.h but didnt worked. //#define digitalPinHasPWM(p) ((p) == 3 || (p) == 5 || (p) ...
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1 vote
1 answer
1k views

Arduino Wire communication with MCP23008 GPIO pin expander to turn on an LED with a button press

I am using an Arduino Uno and an MCP23008 GPIO pin expander, I have a momentary button connected to GPIO 2 on the MCP23008 and an LED light connected to GPIO 1 on the MCP23008. What I want is for the ...
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10 votes
4 answers
516 views

What is the proper way to make library pin mappings configurable?

I am working with some libraries that provide APIs for interacting with specific hardware chips (that makes these drivers?). However, different custom boards or shields will have the chip mapped to ...
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  • 203
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2 answers
34 views

Powering via an I/O Line

I have an SPI 128x64 OLED display. Is it safe to power this display's VCC from a digital I/O pin? I would like to do this so I can connect it flush to my arduino's header, and so I can control the ...
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2 votes
1 answer
2k views

Is it safe to short two pins together for conditioning a sketch?

I want to make a sketch which behaves differently, i.e.: pinMode(pin1, OUTPUT); digitalWrite(pin1, HIGH); pinMode(pin2, OUTPUT); digitalWrite(pin2, LOW); pinMode(pin3, INPUT); // And a user decides ...
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  • 123
0 votes
1 answer
76 views

Purpose of extra pin slots on Pololu DRV8835

I have a Pololu DRV8835 motor controller. I managed to properly solder and connect it and it actually works, however I've been wondering about the purpose of the extra pin slots - especially the ones ...
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6 votes
5 answers
1k views

Adding an LCD to Uno but not enough pins left

I am an absolute beginner and wanted to build a simple home automation system using DTMF module using this guide. My problem is out of 12 pins most of them are getting used in DTMF module(5) and the ...
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1 answer
85 views

Can anyone identify these headers?

I'm very new to the Arduino platform and micro-controller projects in general, which is why I'm still learning about all the parts needed for circuit creation. There is one particular part that I ...
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0 votes
1 answer
8k views

Using all ten capacitive touch inputs on the ESP32

I am using a Wemos Pro ESP32 development board and would like to be able to use all ten of the available capacitive touch inputs. I am able to get readings from nine of them but not T1. Here is the ...
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2 votes
0 answers
80 views

Connecting Arduino Wifi shield to Arduino Uno based Mcore board

I am trying to connect this mBot board to an external network, that's why I bought the arduino wifi shield. I am connecting the wifi shield to the 6pins (5V MOSI GND RST SCK MISO) of the mCore. ...
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1 vote
3 answers
665 views

What not to do to an Arduino [closed]

I may have been working with my Arduino UNO board improperly, because now it fails to upload sketches (says some programmer is not responding) and when I press the cute little restart button, the ...
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  • 369
1 vote
2 answers
582 views

DigitalWrite Cannot Power HC-06 Bluetooth

To save power consumption, I tried to connect the HC-06 bluetooth module to a digital pin of my Arduino Nano. (HC-06 +5V <=> pin 11, HC-06 gnd <=> gnd) In that way, I can toggle the bluetooth ...
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  • 111
0 votes
2 answers
2k views

How can the sensitivity of capacitive touch sensors be limited?

I have an Adafruit circuit playground classic, and the touch-pads are so very sensitive. From a centimeter away, they trigger. I would be happy to just have regular inputs, or to have the sensitivity ...
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  • 838
1 vote
4 answers
6k views

Running a 7 pin OLED with 4 pins (I2C)

I have an OLED with this 7 pin pinout: I want to use an existing code i found that makes use of U8Glib. But in the example, use uses 4 pins to control the OLED via I2C. This is the pinout he uses: ...
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5 votes
5 answers
2k views

Is it possible to make normal pins act like ground pins?

So what exactly I am trying to do is control a motor and be able to turn it both ways without any extra parts. So if the hmp was on (the plus pole) and the hmm (the minus pole) acted like ground the ...
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1 vote
1 answer
9k views

what is aref(analog reference)

what is the analog reference, I know that it can be used as a voltage reference, but not exactly what it is all about please someone help.
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  • 331
2 votes
3 answers
839 views

How can I get additional Slave Select pins?

I have a project where I want to connect a number of SPI devices, and I'm running out of Slave Select pins (SPI) on the Arduino. So I thought that I could use something like an MCP23S17 to get ...
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14 votes
1 answer
48k views

What is an ICSP pin?

What is an ICSP pin? I have read that it is an AVR and a tiny programming header for the Arduino, but what is an AVR and what does an ICSP pin do?
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11 votes
2 answers
2k views

What is the purpose of the I/O pin capacitor on the AVR microcontroller?

What is the purpose of the capacitor on the I/O pins on the ATmega328 (I imagine it's on other AVR microcontrollers as well)? Is it to reduce noise from other parts of the microcontroller?
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0 votes
2 answers
1k views

More than 500 pins

For a project I need 400-1000 pins controlled by one arduino. Each pin should work similar as arduino pin, so something like 5V, 90mA. Is using dozens of shift registers a good idea? And what power ...
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-1 votes
1 answer
55 views

RasPi GPIO into Arduino Digital Inputs

So I'm making a Robot for my AP Comp Sci Class, and I'm borrowing an Arduino, as well as a Pi from the school. What I plan to do is have my Pi output from the normal GPIO pins and into the Arduino's ...
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0 votes
1 answer
450 views

Arduino/Genuino 101 5 volts pin

Still trying to understand the nomenclature of the pins, I am confused of what's the function of the +5V pin, as I read that the 101 should not operate at that tension. What's it for?
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2 votes
4 answers
249 views

Can I cut the pin holes off of my Arduino board?

I'm making a project, but my arduino pro micro is just slightly too big to fit in it's case. What would happen if I cut off the pin holes that I don't need? Would it still work? Or would it be ruined?...
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0 votes
1 answer
221 views

(SOLVED) Fast HW check: (18 digital + 4 analog to I2C ) Arduino Mini Pro + MCP23017 or STM32?

Arduino Mini Pro+MCP23017 or STM32 I want make device, which reads 17 digital buttons and 4 analog, process it somehow and send the result to I2C bus. Also there is a LED to be managed. I may want ...
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2 votes
1 answer
2k views

How to use analogWrite() on multiple pins at the same time?

I would like to do, analogWrite(100,3); analogWrite(200,6); at the same time. But the problem is that only the led on pin 3 lights up. I want both to light up at the same time. I've heard about ...
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4 votes
1 answer
228 views

Need to set an output pin without it going LOW during initalization

For a control system I am using a relay module that controls a larger relay for high-current electrical stuff, as part of a battery protection circuit for my solar plant. This module switches 120 VAC ...
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  • 1,141
0 votes
1 answer
193 views

Arduino IDE compiling for non-arduino AVR boards

Using: Arduino IDE 1.8.2 the board manager from https://mcudude.github.io/MiniCore/package_MCUdude_MiniCore_index.json an ATmega168P MCU in TQFP I was able to run my code successfully by modifying ...
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  • 129
0 votes
1 answer
15k views

What are the unused pins in an Arduino L293D motor shield?

What are the unused pins in an Arduino L293D motor shield? I want to connect the shield using wires instead of directly mounting on top of the Arduino board.
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3 votes
1 answer
5k views

NodeMCU does not boot up when GPIO pin is high

I have a NodeMCU board connected to a door and there is a micro switch that makes one GPIO pin (GPIO15 - D8 in this specific case) go high when the door opens. My problem is if I lose power while the ...
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0 votes
1 answer
573 views

Multiple connections on the same pin

I want to connect an arduino uno both to a TGAM module: http://www.seeedstudio.com/document/pdf/TGAM%20Datasheet.pdf and a bluetooth shield. The arduino is to receive data from the TGAM module and ...
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2 votes
1 answer
392 views

Arduino connection to brainwave analyzing module

I want to connect a TGAM module (detecting brainwaves) to an Arduino Uno. I know little of electronics, can someone advise me? To which pin of the Arduino should I connect the TGAM? How to get the ...
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2 votes
1 answer
369 views

Adding slave device to Arduino Uno-SPI | Configuring pins

I recently started an oled project. I use a small "128X64 OLED LCD LED Display Module" and I control it using SPI protocol(with my Arduino). It is the only device connected to the microcontroller. ...
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2 votes
0 answers
460 views

How can I connect a Fona to an Adafruit feather?

I have this adafruit-feather-huzzah-esp8266: https://learn.adafruit.com/adafruit-feather-huzzah-esp8266/pinouts and I want to connect a Fona board. But I am not certain which pins have the ...
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  • 838
5 votes
3 answers
2k views

How to get number of available pins in code?

Different boards have different number of pins. Is there a way to know this number in code (at least digital and analog pins), or do I have to determine board type (like in this thread) and know the ...
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  • 225
1 vote
1 answer
12k views

How to read NodeMCU GPIO pin status? [closed]

I am setting up a page on NodeMCU running as a web server and I want to be able to turn on and off a light based on the url being clicked. I want to know how I can get the status so that I can set ...
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2 votes
0 answers
496 views

SPI or A0/A1: what is the best solution for pin allocation on an Arduino shield?

When you design an Arduino shield you want to make it compatible with a maximum number of shields that may be stacked with it on an Arduino (UNO). Considering the following two possible tradeoffs, ...
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1 vote
2 answers
229 views

Can Digital/Analogue pins double as power supplies?

I'm doing research into if the Arduino Uno has enough power pin slots to power multiple components, and I'm unsure if it's possible to convert some of the pins from the Digital and Analogue sections ...
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2 votes
4 answers
1k views

How many pins does this circuit (HMC5883L) use?

I've been told 2 by a friend but this looks to only use one? https://www.adafruit.com/product/1746
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-2 votes
5 answers
1k views

How many pins are needed for a sensor?

I'm currently looking to buy an Arduino, but never touched robotics before. Would anyone be able to give me an idea how many pins a sensor such a magnetometer would use? This is for Arduino Uno. ...
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0 votes
6 answers
784 views

I would like to know the ATMEGA wiring to Arduino

I would like to know which pins are connected to the output of the Arduino. For example: PC6 is digital 12 PB5 is analog 13 etc...
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  • 13
5 votes
2 answers
29k 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?
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1 vote
3 answers
1k views

Understanding writing to input pins and pull up resistors

I am new to Arduino, and am trying to understand the following code. The question is: Is my understanding correct, or if not, what is happening here? I have to reverse engineer an existing ...
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  • 113
1 vote
2 answers
1k views

Where is PORTB defined?

On Arduino I can set digital pins by setting special variables PORTB and PORTD (or maybe they are not variables?). Where are those variables defined? I grepped /usr/share/arduino, but found nothing. ...
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