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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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The Capacitive Sensor library on a D1 Mini

I want to set up a hand-made capacitive sensor on a D1 Mini, as in this tutorial, so that I can get specific capacitive readings. But I couldn't get the CapacitiveSensor library to work with the D1 ...
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2answers
46 views

Weird behavior (Couldn't pull the pin LOW)

I was trying to implement my own code to control a stepper motor on arduino uno, however I noticed that the pins were always HIGH despite what was written to them. I started to erase the code to leave ...
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0answers
47 views

Keypad prints just 1 [closed]

I used this example code: #include <Keypad.h> const byte ROWS = 4; //four rows const byte COLS = 4; //four columns char keys[ROWS][COLS] = { {'1','2','3','A'}, {'4','5','6','B'}, {'7','8'...
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1answer
44 views

How to have multiple digital outputs for the same pin on Arduino Uno and Simulink?

I'm trying to develop a PID controller with Simulink as shown in the image PID. I'm using a PID controller to control a motor via an Arduino Uno and motor driver. I have the PID output connected to ...
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3answers
47 views

How to monitor state of 50 Digital Inputs

Good day. I have a specific project need and I spent the past couple of days searching on forum, blogs, etc and I'm still not clear if that's feasible to do with Arduino or not. I need to monitor ...
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1answer
54 views

MCP2515 CAN bus with Arduino

I'm using MCP2515 CAN controller and TJA1050 transceiver. I want to send some square waves to TJA1050 with digital write and delay instruction of Arduino. How can I do that? I also read the MCP2515's ...
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0answers
43 views

Lots of GPIO system using Arduino/ESP8266/Raspberry Pi

I'm searching for a system that can provide and handle lots of GPIO, let's say 256, but also to be relatively low power. One problem would be to handle the output, one idea would be to use a ...
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1answer
129 views

ESP 12 unusable pins

The ESP 12 board has 22 pins Are all of them usable? I understand that there is an external flash memory that is accessed through SPI, but I'm not sure what the impact on the pins is. And if it is ...
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1answer
57 views

The reason for signal not going back to LOW

I have written a simple Arduino sketch, that shall produce a clock signal. Here is the code: void setup() { // put your setup code here, to run once: } void loop() { // put your main code ...
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1answer
41 views

Switch two or more digital outputs of ESP8266 at the same time [closed]

I'd like to control some digital ICs with a ESP8266-12. How can I switch 2 pins to HIGH in the same moment? How can I switch one to LOW and the other to HIGH in the same moment? Is it possible with ...
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1answer
194 views

INPUT_PULLUP not work for D8 in my NodeMCU v3

I changed my arduino NodeMCU application pin mode to use INPUT_PULLUP mode instead of INPUT. D8 input pin is not working as expected, I is always in LOW even the button is pressed or not. I have 3 ...
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2answers
90 views

Checking a jumper between two pins on Arduino

I'm in the process of making a tag scanner (which transfers the tag ID to the computer), and I figured I'd use an Arduino Micro for that and just use the keyboard function on it to save myself a whole ...
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1answer
42 views

How do I connect my Luxorparts keypad to my Arduino?

I just bought a 12 digit keypad from Luxorparts and it doesn't come with any schematics showing how it's wired at all. How do I figure out how to connect it to my Arduino?
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2answers
28 views

Does a pin (input pin Arduino) still float when connected to GPIO on RPI?

I am currently testing my application on an Arduino, and I experience floating pin issues. My program reads the pin status of input pins, which are configured as pinMode(5, INPUT); digitalWrite(5, ...
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1answer
122 views

Uno pin connection: Atmega16u2 & ATmega328P

On my Uno, I set up the HoodLoader2 (link below) so I can program both the ATMega16u2 and the ATmega328P. I can communicate between the two using the serial port. However, I need the serial port to ...
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2answers
742 views

NodeMCU - use flash button as input in loop()

I couldn't find a proper answer on the net so I came here as a last resort. So I want to use the FLASH button as an input in the loop() method. Is there a way the check if it's pressed or not?
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78 views

Is it possible to attach more than two Servos to an Adafruit V2 Motor Shield?

The Adafruit Motor Shield V2 allows two servos to be attached to 3-pronged headers. While the screw-in block terminals enable the use of 4 DC Hobby Motors or 2 Steppers, which are powered by an ...
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1answer
220 views

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
35 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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0answers
104 views

ATmega328p PD0 and PD1 usage

I would like to use pins RXD and TXD (PD0 and PD1 in ATmega328p) as inputs. I am using Arduino Uno to upload a code to my ATmega328p, after that I plug in ATmega to my circuit board. Arduino Uno is ...
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1answer
28 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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1answer
131 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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0answers
25 views

Differentiating signals from piezos connected in parallel

I'm doing a project with multiple piezo sensors and due to conservation of pins and for the tidyness of the wires, I want to use as little pins as possible. For these reasons I'm thinking of ...
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1answer
49 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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1answer
63 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
139 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
177 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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1answer
407 views

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
81 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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2answers
10k views

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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1answer
182 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
57 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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0answers
36 views

Arduino (or similar) board with GPIO pins that can output 80mA - 100mA

I am looking for a board like the Arduino with GPIO pins that can output 80mA - 100mA. Does anybody know if such a board exists?
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1answer
43 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
514 views

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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0answers
2k views

NodeMCU (ESP8266) with SPI TFT, I2C RTC, & 2 Buttons, correct GPIO to use?

From all my research it seems that the NodeMCU only has 11 available GPIO (6-11 are used to connect flash memory chip), i'm wondering if anybody can help me with these final connections I have left ...
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0answers
303 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
137 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
48 views

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
74 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
902 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
76 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
110 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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2answers
3k views

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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0answers
1k views

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
63 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
46 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
62 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
879 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
771 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 ...