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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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How to toggle a pin (LED) simply

I am not a programmer but rather a hardware guy. In the good old machine code days, you could 'read' the status of the port and flip it.. admittedly a much simpler processor. Is it not possible to do ...
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-2 votes
0 answers
15 views

SIM900 GSM SHIELD with nodeMCU pins [closed]

Does anyone knows how to pin out nodeMCU/ESP8266 with SIM900
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0 votes
1 answer
41 views

How do I instruct the L293D to operate a motor at full speed when using 3.3V GPIO pins?

If the L293D enable and input pins expect [up to] 5V inputs; what is the best way to deliver full power to the output pins when using an ESP32 or any other microcontroller which uses 3.3V GPIO pins? I'...
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0 votes
1 answer
35 views

Can pin mode damage Arduino with connected electronics?

I am not that experienced with electronics, so this might be a silly question. But I dont know. Assume that I have connected some electronic circuit (transistors, leds, anything else) to the Arduino ...
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1 vote
0 answers
43 views

Can I use AREF to supply a circuit, when in internal mode? (Nano)

When analogReference(INTERNAL) is set (1.1V), can I use the AREF pin to supply a circuit? E.g. like this: AREF —— R1 —— button switch —— A4 —— R2 —— GND where A4 is configured as analog input (...
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  • 111
10 votes
3 answers
2k views

Why are the pin numbers of the diagrams and of the code different?

If I search Google for "arduino nano pin numbers", all results show that the pin number of D2 is 5. But that did not work. I searched for some sample codes, and they were 3 for D3 and 5 for ...
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0 votes
1 answer
105 views

Problem Using pins A4 and A5 for input and output I2C

Hardare used: Arduino nano ( old Bootloader ) Oled Monochrome Display ( 4 pins, 128 x 32 ) MPU 6050 Both display and MPU use A4 and A5 as I2C communication protocol, They interfere, as the MPU is used ...
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4 votes
1 answer
120 views

Arduino UNO won't move servo

I have a simple MG996 servo motor and I am trying to make it move with my Arduino Uno. I tried different ways of wiring but nothing seems to work as fully expected. For the wiring I followed this ...
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2 votes
2 answers
1k views

Input vs input_pullup

I'm a beginner in Arduino and can't understand some things. How does input pin in Arduino work? I want to set one of the pins as input. When should I use input and when input_pullup? What are the ...
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0 votes
1 answer
205 views

Safe to power LED strip via ESP32 GPIO

I want to rewire a battery powered LED strip (as shown in the picture below) to power via an ESP32's GPIO pin. I have a ESP32 NodeMCU Development Board, powered via USB. The LED strip has specified 3,...
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1 vote
0 answers
46 views

Can I support all these sensors? Will I have enough pins?

So i'm new to arduino and i'm working on a project that will require 3 modules/sensors. I wanted to know, can all of the following modules work with the arduino mega 2560 that comes with this touch ...
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4 votes
1 answer
48 views

Custom LED toggling function: one out of three LEDs misbehave

I connected three LEDs to an Arduino Uno and wrote a simple LED class. I toggle all the leds the main loop, but for some reason one led (connected to pin7) always misbehaves, skips one toggle or stays ...
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1 vote
1 answer
188 views

Select pin to connect RF receiver

I use the RCSwitch library receive signals with a RF receiver. I really need to change the pin the receiver is connected to on my Arduino Uno. What should I change in my sketch? What pins can I ...
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1 vote
1 answer
68 views

Accessing Physical Pins in Arduino Due from Arduino IDE

It is possible to access the Physical Pin 93, Pin PC11 on ATSAM3X8E in Arduino Due from the Arduino IDE? I am programming a Barebone ATSAM3X8E, and it do not seems to be allocated by Arduino Due nor ...
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3 votes
1 answer
53 views

Wirelessly (but fast) transfer STEP and DIR output from Arduino to stepper driver

Very short version: Looking for a way to wirelessly get STEP and DIR signals (only those two signals) from an Arduino to a DRV8825 stepper driver about a meter away: Arduino -> STEP and DIR IO pins ...
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  • 131
1 vote
1 answer
125 views

How to connect an Output to a Pullup Input of another arduino

:tldr; Could problems occur if one connects a HIGH Output of one arduino to a PULLUP_INPUT of another while using differed power sources? Hi I'm building some devices for a LARP Dungeon (think Escape ...
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3 votes
4 answers
619 views

Can internal and external pull up/pull down resisters be used together?

What happens if a sketch uses code like pinMode(18,INPUT_PULLDOWN) to configure internal pull-down (or pull-up) resistors, but is used in a circuit where external resistors are also present? Are there ...
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  • 200
0 votes
1 answer
74 views

Check pin capabilities at compile time

Are there board-independent functions to check pin capabilities at compile time? I.e. Can the pin be used as output, as in digitalWrite()? Does the pin support PWM, as in analogWrite()? Does the pin ...
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1 vote
0 answers
38 views

How to avoid two arduino components using the same digital PIN [duplicate]

I'm trying to build an Arduino project where it involves a TFT and an ethernet W5500 component. Here's the project I want to build to learn Arduino. However I wanted to change the board that already ...
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1 vote
0 answers
44 views

Can I create an hemi-cycle raising signal with one pin and the other hemi-cycle signal with another pin?

I am new to Arduino, I would like to know if someone could help me to create this type of signal with the Arduino Uno. Many thanks!!
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1 vote
0 answers
28 views

Touch sensor trouble

I need help I use Touch Sensor(T)v.0 and it always receives a signal not matter I touched it or not. Here is the code. #define TOUCH_PIN 7 int touchVal = 0; void setup() { Serial.begin(115200); ...
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2 votes
1 answer
1k views

Can't Turn Off Internal I2C Pull-Ups on ESP32

I've designed a custom ESP32 board around the WROVER-IE module. To keep power low, I'm using a GPIO-controlled high-side FET to turn off unused peripherals when in deep sleep mode. The issue: I've ...
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0 votes
1 answer
39 views

I have five pushbuttons that refer to a specific pin number. I need an efficient code to set the variable for the pin with state 1. What can I use?

There are 5 push buttons each which correspond to a certain pin let us use 1 to 5 for an example. I want to set a variable, ActiveButton which will be set equal to the the only pin in the one state. ...
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1 vote
0 answers
29 views

Directly synthesising an OOK modulated LF signal using a CSV file

I'm looking to transmit some data (CSV files) from a measurement instrument underground to a receiver on the surface. I've learned that in order to penetrate the limestone, low frequencies have to be ...
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1 vote
0 answers
35 views

Trouble with laser sensor

I have trouble with my laser sensor it doesn't work properly. When I connect all pins its doesn't work, when I remove GND and connect just the signal pin and VCC it works but the laser light is dim(I ...
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0 votes
1 answer
52 views

Does setting a value always mean setting a Arduino pin?

One thing that always confused me was why we use int or other commands to set the variables to have pin numbers as if those commands were always restricted to pin numbers only. For example int ledPin =...
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0 votes
2 answers
589 views

Portenta pinouts for ADC

I wanted to have your comments about one of my questions. I am currently working on the sketch for the Arduino Portenta H7. However, due to my poor electrical background, I would like to ask your ...
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0 votes
1 answer
73 views

What is the pinout of the Arduino MKR motor carrier when using external power supply, not the Li-Po battery

I see there is a blue terminal connector an the tags below the PCB Vin, 5V, 3,3V and GND, but I am unsure where should I supply voltage to power up the board. Also, in the product page it says the ...
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  • 3
1 vote
2 answers
271 views

Switch on the piezo emitter for a short time

I need a short beep for every minute of change. I wrote a separate function. The signal duration should be 50 ms, the rest of the time the emitter connected to the A1 contact should be silent. A ...
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0 votes
3 answers
202 views

Short circuiting GND and power pins

I have created an arduino shield and i want to measure the voltage between the GND pin and 5V pins, to see if i see a voltage difference between the two points, in order to test if my pcb is fine. My ...
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0 votes
1 answer
105 views

Cant find Sdl and Sca pins in lcd display

My project is of non contact temperature sensor.I am using RG1602A lcd display and mlx90164 temperature sensor. But the problem is, there's no sdl , sca pins in my lcd display. Is there any way, to ...
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0 votes
1 answer
349 views

D1 mini esp8266 error: esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header

I am pretty sure this device worked yesterday. I tried to short GPIO0 to ground (flash), nothing. I have a second ESP that uploads fine, but this one does not. Is their another way to get this ...
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1 vote
2 answers
1k views

How to power Arduino Uno from L298N motor driver's 5v terminal?

I am trying to setup L298N motor driver controller with my Arduino. Different online schematics about how to connect them are mostly similar - but they differ in powering the Arduino from the drive ...
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1 vote
1 answer
78 views

Using same GPIO pins to control multiple stepper drives

I have an Arduino Mega 2560 and I want to control four 23-frame steppers same speed/direction for a conveyor application. I want these to be synchronized exactly as possible for smooth operation. Can ...
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1 vote
0 answers
142 views

ESP-01 and HC-SR04 problems booting up

I have a problem in a project that I am working, basically I need to use a ESP-01 to receive the measurements from a HC-SR04 and send it to another ESP-01 (which I won't cover here). Basically my ESP ...
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1 vote
1 answer
56 views

What pins to use on a Teensy to get data from multiple peripherals?

I'm using a Teensy to keep records on the location, speed, altitude, and direction of a weather balloon I'm hoping to launch. I have an Adafruit LSM9DS1 and a Ublox NEO-M8N with compass (HMC5833L) so ...
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-2 votes
1 answer
43 views

Use a simple LED with no digital pins to spare

Problem: I've made a circuit consisting of an 8x8 led matrix, which uses all of the digital pins on the Arduino UNO board, and I want to add an LED too it. I tried looking around the internet but so ...
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0 votes
1 answer
116 views

Conflicting pins between the PCM library and speaker and the NRF24L01

The PCM library uses pin 11 and the NRF24L01 also uses pin 11. I am using an Arduino nano, and don't know if there is any way to change the pins of either the speaker or the transceiver. https://...
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1 vote
0 answers
34 views

Is it possible to configure uboot without the "Yun Serial Terminal" sketch by using the hardware serial on pins 0 and 1 instead?

Trying to rescue a Yun with the 1.5.3 image. It's not possible to upload the required "Yun Serial Terminal" sketch because the device hangs at U-Boot (hence the rescue attempt). Using putty ...
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2 votes
1 answer
78 views

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 ...
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2 votes
2 answers
711 views

Unable to use analog pins as digital inputs

I want to use the analog pin A7 as a digital input pin. As stated in the Arduino docs the analog pins can be configured in the same way like any other digital pin. However, when trying to configure an ...
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1 vote
1 answer
270 views

Onboard led HIGH and LOW seems reversed

On an ESP32 board I am trying this simple code to control the onboard led. But if I set it to HIGH, led is OFF, if I set it to LOW, led is ON (fully bright). What could cause this ? The board has one ...
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1 vote
0 answers
39 views

3 pin ethernet module?

So basically I'm working on a project that uses an Atmega328 like on the Arduino Uno. I need to receive both DMX (with max485) and E131 (Not both at the same time, I'll decide which with a boolean in ...
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1 vote
0 answers
34 views

How can I use Arduino Analog Uno pins as Digital pins? [duplicate]

How can I use Arduino Uno Analog Pins as Digital pins, So that I can Attach more components like sensors to the Arduino? My 13 pins are preoccupied and I want more.
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2 votes
0 answers
43 views

How to make 16 coin vibration motors and 5 servos work at the same time on a Arduino Mega?

I saw in Arduino Mega's datasheet that the sum of currents out of all input/output pins combined should be maximum 200mA. But I want to make 16 vibration motors and 5 servos work together on the same ...
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2 votes
4 answers
576 views

Why do we use bitwise operators to assign PORTx, DDRx and Pinx?

I have come accross a lot of examples using ways similar to the ones shown below to assign values to the pins. PORTB |= (1<<PORTB2); //set bit 2 PORTB &= ~(1<<PORTB1); //clear bit 1 ...
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0 votes
1 answer
1k views

Az Delivery ESP32 DevKitC V2 PIN names/number

i wonder where to find out the PIN names for the Az Delivery ESP32 DevKitC V2. There is a pin out graphic, but it does not say how the Pin addresses are: https://cdn.shopify.com/s/files/1/1509/1638/...
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1 vote
0 answers
122 views

Understanding the pin diagram for MPU6050 IMU

I was reading this tutorial about the MPU6050 IMU and I was unable to understand why the pin configurations vary so much when compared to this schematic for EasyEDA. The tutorial has this pin ...
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1 vote
1 answer
330 views

Can SoftwareSerial be used in an ESP01

I am using ESP01 as a microcontroller that retrieves information from Firebase and sends them over serial to an Arduino Uno for other uses. I am not using NODEMcu since it has few analog pins and ...
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0 votes
3 answers
72 views

ATMega328 functions, but will not output to any pins

Problem: ATMega328 Refuses to digitalWrite() to any pins, I can upload and run sketches using the board UNO from the ide on the 328 and can confirm it is working using the serial monitor (see code). I ...
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