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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hx711 and load cell read out 0 for calibration

I'm using this tutorial from Sparkfun https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide And using THEIR code. The only difference is I added a delay so it wouldn't ...
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2answers
47 views

Schematic interpretation, where to put resister?

I'm new to schematics, trying to figure out where to put a resistor (no instructions other than the schematic) I'm told I need: 10K variable Resistor x 1, 4.7K Resistor x 1, 100 Resistor x 1 But I ...
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1answer
803 views

What is the best way to configure a bidirectional, open collector data pin? [closed]

I want to communicate with an old keyboard asynchronously through a single open collector, bidirectional data pin. As part of the protocol, the timing will be controlled entirely by pulse width. I've ...
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1k 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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1answer
689 views

FTDI and atmega328p-au [closed]

I want to connect an Arduino Pro Mini with ATmega328P so as to drive a SI4463. But I don't know BLK, CTS, DTR should be connected to what pins of ATmega328P. How do I connect this?
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466 views

How to drive 16 stepper motors with Arduino?

I'm trying to drive 16 of these little steppers on an Arduino Uno. Each test driver uses 4 digital pins for control (2 for each coil) so that would be 64 pins I will need. I'm thinking either ...
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1answer
468 views

Using TTGO TS 1.0 TFT display

I'm trying to use the TTGO TS 1.0 display with a demo app from a different source. The demo app wants the following to be configured: #define PIN_NUM_MISO 17 // SPI MISO #define PIN_NUM_MOSI 23 ...
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2answers
390 views

Share I2C pins with other device when lacking GPIOs

We're Using ESP12E as our MCU and we have three functionality : SIM800 connected to TX(GPIO1), RX(GPIO3) Matrix Keypad connected to GPIOs: 14,13,2,10,0,4,5,16 GLCD connected to GPIOs: 15,12 And we ...
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3 digit 7 segment display

I have 3 digit 7 segment display with 10 pins I found this image pinout but it not working for me I need to know the pin out of this display
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1answer
661 views

Need lot GPIO pins on arduino mega - what are restrictions?

I would like to use as much as possible GPIO pins on Arduino Mega especially with (mis)using pinMode(x,INPUT); and pinMode(x,INPUT_PULLUP); to achieve two things at the same time - drive something ...
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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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716 views

Use ESP8266 GPIOs after Flash Startup

I'm a bit confused about the ESP8266 launching and GPIO behaviour. When I'm programming the ESP8266 I have to set GPIO2 high and GPIO0 low. But when I want to use the ESP8266 in my project I have to ...
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1answer
90 views

Digital Pins reads 1 when configured with internal_pullup

I work with Arduino DUE. I would like to configure few of my digital pins as INPUT pins. When the µc sets these particular 4 pins , the DUE must be activated. Something like a DATAREADY pin in the SPI,...
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1answer
277 views

Connecting CAT5 robustly between portable Arduino and more portable sensors

Newbie wiring question. I’m building a lightwand of some sort, involving an RGB LED and a few pushbuttons that I want to wave around (the “remote”), while staying connected over ~0.5 - 3m to an Uno (...
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1answer
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How do I get a nonzero output from my HX711 and load cell?

I am trying to set up a load cell using the HX711 amplifier. Whenever I upload my sketch, my serial monitor only will read zeros regardless of load applied to the sensor (no signal appears to be ...
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724 views

Pin Mapped Wemos D1 R1

I want to ask about Wemos d1 R1. Can I use those pins connected for different sensor? For example I use pin D5 and D13 for switch and push button, or I use pin D7 and D11 for two different sensors. ...
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1answer
518 views

Interaction between Analog Pins when measuring a DC voltage- a common issue? [duplicate]

Just set up a replacement "Piduino" - a RPi3 connected by USB to an Arduino Uno. The previous one was the victim of a Diet Big Gulp - spilled on the voltage divider breadboard. Whoops. The tiny ...
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2answers
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Upcoming Project [duplicate]

Hey guys I have a project that will require 20 I/O pins with serial communication from a computer to control each of the pins. I would like something as small as possible would a arduino micro or uno ...
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1answer
111 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
5k views

Wemos: relay shield doesn't work on top of the stack

I connected a SHT30 shield to a Wemos D1 mini (one on top of the other) to measure temperatures. Wemos D1 mini (2.3.0): SHT30 shield: It works great but when I added a relay on the top of the ...
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1answer
329 views

Genuino UNO 5V pin is reading 0.3V

So I was trying to set up the LCD screen that came with my Genuino starter kit when I noticed that the board screen did not power on at all, unlike a few days ago when it worked. In order to verify ...
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2answers
1k views

How do I use digital pin on sensor to analog on arduino uno

I am working on a autonomous fire extinguisher.i have run out of pins.I have the following question in my mind while working on my project Is it necessary that the DO pin in a flame sensor must be in ...
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Use LoLin V3 pins starting with 'S' in Arduino

I have this LoLin NodeMcu V3 board: What are the pins S3, S2, S1, SC, S0, SK? Can I use them as GPIO in Arduino? Thank you for your help!
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WEMOS D1 MINI NodeMCU, how to correctly powering it?

I'm developing a simple project using a WEMOS D1 MINI NodeMCU to drive an rgb LED strip so I managed to use a 12V power source to drive the current to the 12V pin of the led strip, a STEP DOWN ...
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2answers
223 views

simultaneously read 16 hall sensor and maximum current allowed by Arduino

My question is about maximum current allowed by Arduino. I know it's 200mA in Arduino and 40mA in every pin (lower in arduino mini). Just wondering if simultaneously read 16 hall sensor (than can be ...
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1answer
66 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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2answers
74 views

Can I support all these sensors?

I'm new to arduino's and am currently working on a project which requires a lot of different sensors. I was just wondering if its possible to use all the following sensors on a single Arduino Uno: 2 ...
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3answers
936 views

Fool Proofing My Arduino IC Checker [closed]

I am creating an IC checker for some high school juniors since a faulty IC can be a nuisance of a bug to find when bread-boarding. These ICs are all simple TTL gating from the 74LS series; the set I ...
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1answer
3k views

Relay active low and ESP8266 GPIO pins

I am using a ESP8266, specifically the ESP-12-E : I have a Relay, SRD-05VDC-SL-C connected to GPIO pin 4. It is wired in Normally Open(with my device to be powered wired into the top and middle pins ...
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2answers
11k views

Arduino Uno R3 to Wemos D1 R2 project migration - Pinout problems

So i've chosen to purchase a Wemos D1 R2 board in order that my old Arduino Uno R3 projects can get some new IoT features. However, even if my code is working in Uno perfectly, i want to test it using ...
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3answers
72 views

How do I create a constant loop with an event that only occurs once?

I am currently working in void loop() and have setup a distance meter that constantly checks the distance. Once the distance threshold is met, a function is called. Now I only need this function to ...
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2answers
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What's the difference between DDRB and pinMode?

It's my understanding that the following lines are equivalent. They seem to be interchangeable in my sketch: DDRB = 1<<DDB0; and pinMode(0, OUTPUT); Is the first form (DDRB...) setting a ...
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2answers
268 views

Accessing digital pins from the Atmega 16u2 on the Uno

I'm running a custom firmware on the ATmega16U2 (Switch-Fightstick). Is it possible to access the digital pins of the UNO from the ATmega16U2?
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3answers
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Is my HC-SR04 sensor broken?

I am extremely new to Arduino and electrical engineering, and the project I am attempting involves a ultrasonic sensor. I am using the HC-SR04 with the Elegoo Mega2560 Arduino board. A few days ago ...
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2answers
4k views

Fill an Array with Values

I have a function in which I change the pinMode on many of my Arduino's pins based on a passed in mode. I first construct an array of bytes specifying each pin to be an input or an output and then I ...
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1answer
244 views

Consequences of dynamically changing input/output configurations of digital pin?

I am creating an IC checker for a large chunk of the 74ls series (basic TTL logic chips), which means that I have 14 pins running to the IC to verify its functionality. One pin is power (+5V) and ...
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1answer
4k views

Connecting multiple component's VCC wires to one Arduino UNO R3 5V Pin

Apologies for the title gore and whether this seems to be a fairly basic question, I'm an Arduino noob. I'm working on a wearable sensor system project at my university using an Arduino UNO R3 to ...
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2answers
220 views

How to identify RGBW LED pins? [closed]

I have a RGBW LED but I don't know how to identify the negative and the colors pins. I tried different combinations with an Arduino Uno but it never produce light. I never used it so I am not sure ...
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1answer
4k views

Which input pins can I use on the ESP8266 NodeMCU

On the ESP8266 NodeMCU I have GPIO2 , GPIO3 , GPIO1 , GPIO9 free but when I assign them to a button they do not work. I assume it is because those pins have other function behind them. When I look at ...
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2answers
160 views

Can I change Vcc to some other pin?

I was working on an Arduino Uno and while carrying it to my teacher the wire's pin got stuck into the Vcc of 5 V. Can I set Vcc to other inputs? If so, then how?
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1answer
906 views

What do the pins on this KS0107+KS0108 display do? [closed]

I got this display on ebay and I have no instructions on how to use it. I can guess what most of them do but I'd rather be sure I know what they all are instead of messing around trying to guess. The ...
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2answers
2k views

Arduino & RPi communication via GPIO [closed]

so I'm working on communication between arduino and RPi via GPIO pin. It's basically connecting them by using a cable jumper. So I have a 2 channel relay shield attached to my arduino, and I've been ...
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3answers
5k views

can arduino on output mode sink current?

I have a arduino set below: pinMode(1,OUTPUT); digitalWrite(1,LOW); Now, I am expecting 1.2mA current flow through the pin that is set as output. Is that accepted? If so, what it the max current a ...
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1answer
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How to determine which pins_arduino.h file is used?

For some applications I need access to the registers that control the output/input and high/low state of pins. For example pin 10 on a adalogger is PORTB with a mask of _BV(6). This information can ...
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1answer
129 views

Arduino industrial 101 digital pins

I don't see anything that has been clear about which digital pins map to which physical ones. If someone could point me in the right direction it would be a big help. For exampleThrough trial and ...
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1answer
2k views

How to keep a pin LOW for a small amount of time after pushing a button and while device is booting?

Context I keep the board in deepsleep mode and want to wake it with different buttons. I need to know which button has been pushed on boot. The board is immediately put back in deepsleep mode ...
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2answers
2k views

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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1answer
886 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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2answers
4k views

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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2answers
308 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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