Questions tagged [gpio]

GPIO stands for General Purpose Input Output and can be used to receive and send digital signals to and from simple electronics from the Raspberry Pi.

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19 views

Choosing GPIO for Chip select SPI on Rpi 3B+

I would like to ask what GPIO pins are best suited for Chip select. The Raspberry Pi 3B+ and Raspberry Pi 4 has 2 chip select GPIO 7 and GPIO 8 but i have 6 slave devices (MCP3008 A/D converter). As ...
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22 views

Callback parameters to GPIO.add_event_detect?

I have a button object that when pressed needs to perform something, and for this I'd need to get a property of the button. I'd like it to work like: ... GPIO.add_event_detect(button, GPIO.RISING, ...
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79 views

DHT11 Temprature sensor makes raspberry pi go crazy!

I am trying to use the DHT11 sensor temprature and humidity sensor with my Raspberry Pi 4B. When I connect the sensor with my Raspberry Pi and turn it on, the red LED on it starts blinking and it can'...
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Can 4 cameras work together when connected to raspberry pi? [duplicate]

I need working of 4 cameras simultaneously, so how can I connect 4 web cameras to single raspberry pi and can then take input simultaneously?
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how can i connect 4 LCD screen, 4 cameras and 12 led lights to a raspberry pi and can they work simultaneously?

I want to build a prototype for an intelligent traffic signal system for a four-way cross junction, hence I need to connect 12 led lights i.e. red, yellow, green and 4 cameras for taking input images ...
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pad4pi (rpi_gpio) Library “registerKeyPressHandler” not working as expected

I'm currently writing a python program, that initializes the fingerprint sensor at first then showing the number of used templates on the fingerprint sensor after pressing "1" on the matrix membrane ...
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56 views

Using an NPN transistor to amplify 3.3v GPIO in order to control a 5v motor controller input [closed]

I am trying to control some 5v stepper motor driver inputs using GPIO. I found this helpful tutorial and was able to get it working (scroll to the last post where he's got it rigged up to a ...
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2answers
51 views

Adding I2C Bus with dtoverlay Does Not Show Up in i2cdetect

I am trying to set up multiple I2C interfaces on my pi. I have added the following lines to my /boot/config.txt and rebooted: dtoverlay=i2c-gpio,bus=4,i2c_gpio_delay_us=1,i2c_gpio_sda=29,...
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148 views

USB GPS to GPIO (route/translate)?

I may be asking about something that has already been done, so apologies if that is the case... I have a USB GPS plugged into one of the USB ports on my RPi(2). It works now in that GPS data is ...
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542 views

GPIO pin PULL_DOWN would

I have set up a Arduino to send a 3.3V signal to my RPi if an object is detected in front of the UltraSonic sensor. I have measured the signal at 3.26V. But it does not work. Since the signal from ...
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PiGPIO Library Example for Bit-Banging a UART

The PiGPIO library http://abyz.me.uk/rpi/pigpio/index.html mentions that one of it's features is "software serial links using any user gpio". I take this to mean that you can use it to generate a ...
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169 views

GPIO is not working

We recently bought two Raspberry Pi 3 B from Cana Kit. We observed that some of the GPIO pins are not functioning properly. More specific details below. We tried to change the state of GPIO pin 7 to ...
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118 views

Lighting an LED through Pi 4 Model B using Assembly

I have been struggling to light an LED using my raspberry pi 4 model b but have not been able to find a solution. My assembly code : .section .init .globl _start _start: mov r0, #0xF0000000 orr r0, ...
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How to make GET request when a button is pressed on GPIO - RPI?

How can I make a get request when a button connected to the GPIO on Rpi is turned on and off? Preferably on Windows IOT. I have 2 URLs that trigger an IP relay on and off depending on the url. ...
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155 views

Pigpio not calling Callback for first rising or falling edge

I have some sample code (taken out of my larger program) that regularly (but not always) missing the first rising edge: #!/usr/bin/python import pigpio, time def callback(g, l, t): print("Callback ...
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107 views

WittyPi on Pi Zero W - I2C read / write fail

I've connected WittyPi2 (an RTC Power Management hat) to my Pi Zero W - but I'm constantly getting failures in the log, to do with the I2C communication: I2C read 0x01 0x68 0x09 failed (result=), and ...
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303 views

Is the gpio readall command compatible with RPi 4?

It's already a while since I got my Pi 4, but never used the gpio readall command until yesterday. I have run into an interesting error. pi@raspberrypi:~ $ gpio readall Oops - unable to determine ...
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62 views

5V relay (jqc-3ff-s-z)

Is it possible to use an external adapter for the 5V, so connecting the + from the adapter to VCC of the relay and the - of the adapter to GND of the relay. Then IN to GPIO27. Setting this low will ...
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46 views

Using two sensors that require the same GPIO pin

So I'm getting into GPIO and the first thing I want to do is connect a sensor and a RF controller. The thing is both 'sensors' require the same GPIO pins, so my question is can I still use both with a ...
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140 views

Raspberry Pi Johnny-five.io and GPIO pins

My code looks quite similar to this: board.on('ready', () => { const motor = new five.Motor('GPIO17'); motor.start(255); } The problem is that when I run the code, its gets error: Unknown ...
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111 views

Raspberry Pi 3 boots to log screen but then turns off and again turn on

I was facing problems from previous days that some GPIOs don't work and then for some time Pi didn't start. Now it starts but just for 2-3 seconds. I see the debug log when generally Pi starts, but ...
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Boot behavior, Pi 3 B+ won't boot with GPIOs connected, 3 B boots fine

I have a 40 pin ribbon which connects an RPi 3 B (SPI and GPIO) to another microprocessor. It seems to work fine on a 3B. I've recently found out that if I connect a 3 B+ instead the Pi will not boot, ...
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230 views

TFP401 LCD flickering with Rasp Pi

We have bought two modules Rasp Pi 3 module and TFP401 module (with touch screen). While driving PWM signal <1KHz, we are seeing flicker on LCD. If PWM signal source is external, no flickering on ...
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34 views

Why the same GPIO pin is not working anymore?

I was working with a very simple code: import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(24,GPIO.OUT) GPIO.output(24,GPIO.HIGH) But after running one time when I am running the code nect time ...
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203 views

Stepper Motor Not Responding. Wiring Issue?

I am following the tutorial: But I am using a pi t-cobbler and a Pi 2. I am also using the ULN2803 driver. When plugging a button into the appropriate gpio spots on the breadboard, I am able to run a ...
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413 views

Does the run pin p6 pin 2 connect to ground

I already know that the run header resets the Pi. My question is does one of the pins lead directly to ground? I would like to use a common ground on the GPIO pins and connect it to the run pin 1. Is ...
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258 views

Programming RPi Hub module with EEPROM to use pins as GPIO output?

I have been working on a project recently that is going to require more GPIO pins than the Raspberry Pi can provide. In order to add more I purchased a RPI-Hub module, though the data sheet says it ...
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1answer
956 views

Correct wiring for multiple analogue sensors?

I’ve recently embarked upon a project that I’ve wanted to do for a while. My overall plan is to have 3 planting shelves; each will have its own soil moisture sensor, water pipe and LED lighting. The ...
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355 views

Why does an analog LDR (KY-018) work on the Raspberry Pi 3?

I'm doing a project and my teacher told me that the GPIO pin cannot supports analog inputs like the LDR, so I went to try and it works perfectly without the Analog Digital Conversation IC. Why is that ...
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1answer
257 views

Button isn't triggering in python script

Software guy here, first time doing hardware. Here is my breadboard setup (yellow is GPIO-8, green is ground): Here is my Python: import RPi.GPIO as GPIO from time import sleep GPIO.setmode(GPIO....
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254 views

Script Running in Background GPIO.cleanup() on shutdown

I have been searching for answer to this. I have python script that runs on start up via cron, and lights up some different LEDs based on button pushing using the GPIO pins and runs in the background ...
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72 views

SIM7600E-H-4G-HAT Raspberry Pi Setup

I am trying to get a SIM7600E-H-4G-HAT running on my Raspberry Pi 3B+, but it is not working. Here is what I've done so far: Inserted my SIM-Card, connected the antenna to Main, connected the entire ...
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235 views

Connecting a servo to GPIO when using touch screen to GPIO socket

I bought a Raspberry pi 3, along with a touch screen that connects to the board, to all the GPIO pins. I wonder how can I use the GPIO port for additional functionality, e.g. connecting servo motors ...
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32 views

using Pi Zero W GPIO relay control

I am trying to control my relay with Raspberry GPIO. Using the terminal to write to gpio5 (Physical 18, BCM 24) works: gpio mode 5 out gpio write 5 1 Trying to do the same in my c++ code doesn't ...
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331 views

Pi4J kills USB bus?

Hello fellow Pi enthusiasts :) I am currently attempting to control a standard 16x2 character LCD display from the PI's GPIO pins from Java. I downloaded Pi4J and wrote a small program to initialize ...
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1answer
131 views

Controlling a High Power 13V DC Motor with in-built Hall Effect sensor

I am a beginner with electronics and RPi. I have a Brushed DC Motor that runs at a constant 13V and draws about 4-5 A while running and about 18-20 A at stall. It also has a single Hall effect sensor ...
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104 views

File transfer between raspberry pis via GPIO pins

I'm trying to send image(3MB) captured by one pi to another pi, external WIFI or setting up one pi as AP is not possible due to strict regulations, all I can use are the two wires. Currently I'm ...
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421 views

How Much Current for GPIO Power Supply?

I'm working on an audio project where the Raspberry Pi will be powered off the GPIO. I was trying this using an LM7805 voltage regulator to get 5v from the 9v power supply that is standard in a lot of ...
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73 views

Wiring Pi Issue - #!/bin/bash vs #!/bin/sh

I am working on a project and have an application shell script. For function part, I need the GPIO access, and for that, I am using the standard wiringpi package. The issue I am getting is with the #...
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3answers
34 views

Is it possible to use my raspberry pi as a network hub?

I want to create a network hub with the help of raspberry pi for connecting 2 standalone devices with the hub and then provide internet to the hub so that both the devices can access the internet ...
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1answer
281 views

Parallax RFID Serial Not reading tags

I am a complete newbie with Raspberry Pi and any type of hardware prototyping. I have been trying to get a Parallax RFID working with my Pi 3. I currently have it wired to the GPIO using BCM and the ...
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46 views

Communicate with GPIO HIGH/LOW between 2 PIs

I have 2 raspberry PIs 1x PI3 and 1x PIZero with camera attached. I want to set up a system to have a output GPIO pin on the PI3 and a input pin on the pizero connect so that when I set the PI3 pin ...
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258 views

GPIO stop working nodejs Raspberry Pi, Gpio no longer enable

2 months ago, I configured my raspberry to use GPIO. I don't remember exactly what I did, but I do remember needing to configure something to enable GPIO. It worked great. 2 months later and multiple ...
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133 views

What happens to the GPIO voltage after shutdown?

I don't have a Raspberry Pi laying around at the moment and I would like to detect if my Raspberry Pi is shuted down. My Idea is that maybe after the Pi shutted down the Voltage at the 3V3 pin will ...
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37 views

Can GPIO detect if Pi is fully shut down?

Scenario: headless Pi. By glancing at the state of an LED that's plugged into the GPIO, I want to know if the Pi is fully shut down or not so I can pull the plug. For example: Pi on --> LED on. Pi is ...
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Hardware controlled RTS on a Pi4 not working accurately

We need to use RS485 to talk to one of our custom tools. We need to use hardware controlled rts/cts. I've read so many articles about this but nobody ever says it works for them with fast timing and ...
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3answers
2k views

Can't read/write to GPIO as non-root after export

This is driving me crazy. I do this: cameron@raspberrypi ~ $ gpio export 18 out Then here's the output of sudo ls -lL /sys/class/gpio/gpio18: -rwxrwx--- 1 root gpio 4096 Mar 8 10:50 ...
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433 views

sh: can't access tty: job control turned off

I own a raspberry pi model B revision 2 and when I switch it on, it gives me the following error message: sh: can't access tty: job control turned off I researched through the internet for a ...
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242 views

Controlling ATX power with HAP-NodeJS

I want to control my PC power via the ATX headers on the mainboard. To trigger power and reset events the two corresponding pins on the mainboard have to be short circuited i believe. Can i achieve ...
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445 views

Powering a 5 volt fan from GPIO

I found a 5 volt fan from an Acer laptop, and want to fit it to my Pi (sunon maglev fan GC055515VH-A). It has three wires - red, black, and yellow - why is that?! The unit does not state its ...