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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195 views

Issue connecting heartbeat & temperature sensor on arduino uno but working individually

So the code is working individually for temperature sensor and for heartbeat sensor but when i combine it together it shows wrong values for the temperature sensor I'm using lm35 temperature sensor ...
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1answer
29 views

Do some arduino pins give signals when the controller starts?

For example, on the ESP32 board there are several contacts that can issue pulses when the controller starts, which is connected with the operation of the chip itself. It is not recommended to connect ...
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1answer
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Can I power Raspberry Pi 3 via 3V3 and GND pin? [closed]

Can I power my Pi 3 using the 3v3 pin (pin 1) and GND pin (pin 6)? Also, if I want to protect the board from power surges can I just put a fuse between my power supply and the 3v3 pin? Thanks in ...
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19 views

Pin Mappings from Arduino Metro M4 Express Board to SAMD51

After looking through the internet, I coudln't find any document (not in the datasheet, no nice graphics on google image searches) that showed the mapping between the Arduino breakout board and the ...
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26 views

Made a light controller for the holidays

I am a new the world of Arduino. I found on YouTube, how to build a light controller (https://www.youtube.com/watch?v=WvG9c84ApFA&t=39s). I follow every step but it doesn't work. Here are some ...
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1answer
27 views

Connecting 2-pin JST PH connector to Arduino Mega

I’m want to connect 50 LDR to my Mega, I wondering if I use a 2-female pin JST PH connector to connect the LDR, how can I link 2-pin male JST PH connector board to the Mega and does this board exist?
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29 views

HC-SRO4 always returns zero no matter what I do?

Wondering if it's the sensor or the code? can anyone help? I've used the code here /* HC-SR04 Ultrasonic Sensor with LCD dispaly HC-SR04 Ultrasonic Sensor VCC to Arduino 5V GND to Arduino GND ...
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2answers
62 views

Can a pin be Neutral, not high or low?

I'm trying to figure out a way to controll a DFplayer mini mp3 player with ADkeys. Because I only have two or three files to play at a fixed volume I find it easier to just use the ADkeys. https://...
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1answer
97 views

How come some Arduino Nano pins (D3, D4, A3, A4, A6, A7) cannot be set high?

I made a sketch to switch on all digital and analog pins, and found out several pins did not work as expected. Note: I manually put a jumper wire from each digital and analog pin (one at a time) to a ...
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35 views

Running out of GPIO & looking for suggestions

I'm working on a project using a NodeMCU and am quickly running out of GPIO pins. I'm trying to decide which way to go to complete it. Right now, I have the MCU connected to a MAX31856 PT100 ...
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63 views

Using a 122x32 LCD display with u8g2

I recovered a 122x32 graphic LCD display, its reference is NMTB-S000087FYHSAY-04. Here are some pics It was retrieved from a completely rusted object, but the screen seems to work. It is a 122x32 ...
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1answer
19 views

Can I disable the TX pin by setting its mode to INPUT while still receiving data on the RX pin of a UART?

I'm using the ATmega328PB in a personal project with MiniCore. My board streams data in on the RX pin from another microcontroller, but my board also has a DIP switch connected to the TX pin, that's ...
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31 views

Creating WebServer with 5000 port with AT command(ESP-01f)

I'm setting webserver with toggle led. I want to create global webserver. I`m mean hat use server with global ip. For it I must use port too. global ip/local ip:port. I want to create on 5000 port. I'...
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1answer
30 views

Arduino Due Digital Inputs without Response

On two of my Arduino Due, when connecting the pin 3.3V to any digital inputs (37,36,35,34), no serial message nor LED_BUILTIN is thrown as output, only the Test message. Digital Pins are set as ...
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1answer
74 views

Output 3.3V when setting pin to high

I would like to pass 3.3V and Ground to an component. How can I achieve such a thing? I for example would like to let a wire get 3.3V when I for example do digitalWrite(pin, HIGH). It is hard for me ...
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35 views

How to set cables to connect Cp2102 to Pro Mini?

How to connect the cables in order to program the pro mini with the CP2102 usb interface ? The TX RX and GND is easy, but I am not sure about the RST, DTR, DST, etc I attached the images of both. ...
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2answers
184 views

measure +3V and -3V through resistor divider and switch on/off by digital pins

I've seen that resistor dividers can be used to read negative voltages, but I'ld like if there is a way to accomplish this with less components and having a way to turn this off. I was thinking if ...
2
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1answer
34 views

Which sources of randomness are available? [duplicate]

I need a souce of randomness to generate a seed to pass to randomSeed. Where can I get this randomness from? Well, I hear I can read random noise from an unconnected pin. But I need to connect 9 ...
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1answer
699 views

Can I use the PWM pins as regular digital input/output pins?

In regards to the arduino which has pwm pins, can I use these pins as normal input/output digital pins or not? Thanks in advance.
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0answers
36 views

HC-05 Bluetooth module on breakout board with straight header pins

Has anyone found the HC-05 bluetooth module (on the breakout board) with straight header pins? I seem to only be able to find them with the 90 degree header pins. Removing those and soldering on ...
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3answers
92 views

Is there an alternative to soldering to connect boards?

I know that shields are usually soldered to headers so they can be attached to the board with the Arduino. I have a tremor, which makes soldering impossible. Are there ways of connecting PCBs without ...
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1answer
32 views

Spi based pin expander for Arduino

I don't have enough pins on my Esp32 board. I would like to use a pin expander. All the ones I could find online only use i2c. Are there ones available that use SPI? I would like send pwm signals to ...
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1answer
24 views

What type of power supply is the Arduino Due’s 5v pin and what is its current?

I’m looking to use a Futaba Servo with my arduino Due and was told it requires a “high current 5 volt supply” and I don’t know much about current so excuse my arrogance. I know the arduino Due has a 5 ...
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2answers
45 views

Ways to add pins in an arduino

I'm making a project for school where I'm using flex sensors and converting that into words on an LCD (similar to the signing glove if you're familiar with that). I ran into a problem since the ...
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1answer
60 views

Nodemcu ESP12-E (ESP8266), Can I reprogramming when the UART pins are defined as GPIO?

I wonder if there may be any problems using the pins that the UART are using as GPIOs, if now I want to be able to reprogram the circuit? (Of course I will detach the ESP12-E from the mainboard before ...
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3answers
41 views

For Arduino Uno it is possible to use the digital pins with PWM to read analog data, is this also possible with the Wemos D1 Mini?

I want to read out data from a load cell, for this I seem to need 2 analog input pins, the Wemos doesn't have this. In the Arduino I was also able to use the digital pint with PWM, there are also ...
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0answers
22 views

How to stop and repeat a melody using a button?

How can we make our melody stop when we press the button the first time and repeat the melody when we press the button the second time? // Noterna defineras #define NOTE_B0 31 #define NOTE_C1 33 #...
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1answer
51 views

What is the maximum number of sensors that can be operated on a single Aurdino unit

I currently have an Aurdiuno uno and a motor driver shield: (http://www.hobbytronics.co.uk/arduino-motor-shield). Now, I would like to run the following mechatronic devices: 3 bi-direction motors, 1 ...
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2answers
50 views

How can I discard power from a device I want to read from?

I want to read the data line from a device that normally interfaces with a controller. It has 3 pins, 3.3v power, gnd, and data. I don't need the power line since the Arduino will be USB powered and I ...
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0answers
239 views

NodeMcu SPI boot GPIO 15

On the esp8266 you've got to pull down the pin GPIO 15 to ground on boot. Otherwise the chip won't boot. However, the boards only open SPI interface has it's ChipSelect (CS,SS,..) on the same pin! Now ...
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2answers
143 views

How to hook up led matrix 1088AS to a PCA 9685 servo controller? there is a way? [closed]

I'm confused about the pinout, I can't figure out which physical pin of 1088as red led matrix must to hook up to the PCA9685, if there is a way to do this I found this image the final target is to ...
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0answers
27 views

Serial Communication between ESP-01 and arduino [duplicate]

I want to send sensor data from arduino to esp-01 and it further goes to firebase. And also wanted to send status of water pump from firebase back to the arduino to control motor manually. So what pin ...
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0answers
61 views

Cannot write pin LOW

All the other examples I've seen have had coding errors where they set a pin LOW in a loop with no delay so that it goes high again right away - but this problem is different, and probably something ...
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0answers
44 views

MOSI pin not turning low [duplicate]

I have the following code: #include <SPI.h> void initChips(){ SPI.begin(); SPI.beginTransaction(SPISettings(20000000, MSBFIRST, SPI_MODE0)); pinMode(SS, OUTPUT); ...
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2answers
132 views

What data type are the analog pin labels (A0, A1, etc)?

Arduino Mega I would like to have an array containing analog pin labels something like... int analog_pins[] = {A0, A1, A2, A3}; int num_analog_pins = sizeof(analog_pins) / sizeof(analog_pins[0]); ...
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1answer
119 views

Mini ethernet shield pins don't have SI

Please somebody who had the same issue help me. The question is how to connect this Mini Ethernet shield to an Arduino. The main problem is the pins that my shield have or haven't; my current ...
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1answer
146 views

Cannot set MOSI pin low even after ending SPI

I'm building a battery operated device and must shutoff MOSI pin during sleep because it leaks current through the SD card if I don't (about 400 µA). Problem is, it won't stay off. I've looked at ...
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1answer
53 views

Question on pin management using PCA9534PW IO Extender

There is an IO expander PCA9534PW, Arduino UNO. I don’t really understand how I can manage this expander using UNO over I2C. I found an example, but here is the reading mode. What I need: Set the ...
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0answers
30 views

digitalWrite on Trace SWO pin

I'm using STM32(generic board) and I want to control bi-color LED(common anode). STM32 pin layout and scheme is below, so please see it. Now, in theory scheme Works, but in practice it Works halfway. ...
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1answer
61 views

arduino is skipping the if statement [duplicate]

Hi guys I am new to this language and i just tested the code to control a servo motor Can anybody help me please ? here is the code void setup() { servo_test.attach(3); pinMode(9, INPUT); ...
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2answers
64 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 ...
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0answers
62 views

Bit Bang I2C with port manipulation on AtTiny84: new pinout doesn't work

So I am trying to understand bit banging and port operations. I'm developing a breakout board with an ADXL343 IMU read by an AtTiny44 via i2c. I adapted this code from MIT's How To Make Almost ...
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0answers
29 views

ESP12e pin 13 won't set to output/won't work

I have an ESP12e and running a basic blink code on it. The problem is that GPIO13 of esp12e wont turn on. I have noticed that this has happened from time to time. Earlier I thought that the ESP was ...
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2answers
209 views

ATmega 32A and 2560 R3 register to pin mapping?

I've been doing research for the last few hours trying to determine the mapping of physical pins to memory-mapped I/O registers for the Arduino Mega board (which is an ATmega 2560 R3). My code is on ...
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2answers
104 views

What is the state of Arduino pins when the arduino is unpowered?

I'm building a control box to provide logical control of power outlets. I'm using a 4 channel 5V optically isolated relay system to control 4 separate outlets. To use optical isolation you connect ...
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2answers
71 views

Can you current-limit Arduino 101 GPIO pins?

A number of questions ask about max possible in/out current on a GPIO pin, that's not my question here. I'm asking if it's possible to set a maximum current limit on a GPIO pin, such that any attempts ...
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1answer
260 views

Detect power interruption on NodeMCU

Im using a 5v 1A power supply and connected to VIN pin on the NodeMCU. I also use 18650 battery to keep NodeMCU running in case the power supply shuts off due to power interruption. I'm planning to ...
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1answer
63 views

toggling Rx, Tx pins after Serial.begin

What should one expect when the following program runs on Arduino Uno? void setup() { Serial.begin(9600); DDRD |= 0b11; } void loop() { PORTD |= 0b11; delay(100); Serial.print("...
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1answer
363 views

esp32 spi library, how read a mcp23s08 register

thanks for any help I need to read a gpio expander mcp23s08 set as 8 bits input. my code write correctly (I believe) the setup register using SPI library, with the enclosed example modified. But I do ...
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1answer
65 views

How can we use two devices at the same time with arduino?

I am using fingerprint module r307 and LCD together. In that, I am using 2,3 digital pins of arduino for data transfer to the fingerprint.(I tried other pin configurations for this but it didn't work) ...