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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How to disable output to serial (GPIO) during boot

I'm trying to drive a motor control over the Raspberry Pi's GPIO serial pins (GPIO 14 and 15) I've disabled the serial console, however, during bootup of the Raspberry PI, it still sends data over ...
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What are the alt functions of GPIO FL0 FL1?

I am going through the raspberry pi compute module and deciding which gpio pins to use for status led and LAN_RUN for LAN9512. Seems like GPIO 31 and 33 have the least important alternate functions. ...
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I2C (and SPI) - Byte-by-byte

I would like to read multiple bytes from an I2C device but only one byte at a time. For example, to read 10 bytes from an I2C real time clock I would issue a single read command (send device code ...
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300 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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166 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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567 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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1answer
476 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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1k views

Problems triggering via GPIO

I am building a network of Raspberry Pis, and want a lot of Raspberrys to take a picture after receiving a Trigger Signal. I want to send this Trigger Signal via a GPIO Pin. It sounds simple, and I ...
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How can Rpi3B+ GPIO input IR signals direct from Optoma HX180X projector's remote control CN1082?

I am trying to record the IR codes from my projectors remote. Nothing seems to be working and I need some help. I want to be able to directly record the IR signals that my remote is putting out when ...
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1answer
21 views

How do I use a Raspberry Pi to install OpenWrt firmware on a BT HomeHub 5a or PlusNet Hub One router

I have a spare BT HomeHub 5a clone (actually a PlusNet Hub One router). I would like to install the OpenWRT firmware on it, in order to reliably use it as a wired wifi range extender without a DHCP ...
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Rpi ILI9341 2.8" 240 x 320 5110 SPI TFT LCD Screen Setup Problem

I ordered a cheap 2.8 inch ILI9341 screen from Amazon (https://www.amazon.co.uk/240x320-Screen-Serial-Module-ILI9341/dp/B07MXH92RL/ref=sr_1_12?dchild=1&keywords=spi+screen&qid=1589230039&...
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What are the specifics regarding schmitt trigger inputs to the gpio?

There are some references to the existence of Schmitt trigger inputs on the Raspberry Pi. There seems to poor and conflicting information on this point. There is https://www.scribd.com/doc/101830961/...
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How to turn power off on 5V dc gpio pin with python

I was wondering if there was a way that i could turn the power on and off on the 5V gpio pins with a python script. I am powering a fan with the 5V gpio and was hoping to do something where the fan ...
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19 views

What's the difference between SPI CE0 and CE1 and any other GPIO?

What's the purpose of specifying SPI CE0 and CE1 when you can just toggle regular GPIO?
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What can be done to plug extra V5 output?

I'm currently playing around with the RaspberryPi 4 and a couple of sensors, each of them using a 5V pin. I was wondering if I could plug another 2 sensors - could I output 5V from any other GPIO pin?...
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How can I expand the 5V pins?

I require 2 more 5v pins to be used - as I would like to avoid welding the 4 wires directly to the 5V pins, I wanted to know if it would be possible to expand those pins. I would require a small ...
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Reading Mitutoyo digital micrometer with rasberry pi

Im trying to read the value from my Mitutoyo digital micrometer 543-390B Datasheet. The micrometer is using a smartbox to communicate with PC, the box is using P87C51SBPN microchip P87C51SBPN ...
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GPIO library for C

I want to utilize the GPIO pins on my Raspberry Pi 2, but I'd rather not use Python since I personally dislike the language. However, I cannot seem to find any information regarding the use of C, only ...
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Using GPIO.add_event_detect with kivy

Hello Raspberry Pi people, I am using Kivy v1.11.1 on my Raspberry Pi with Python v3.7.3. The goal is to use a GPIO input to toggle the button state (parallel use of a real button and the touchscreen ...
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214 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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Generating CW from GPIO

I'm working on a project whereby I want to use the Pi to send some morse code (CW) over FM by feeding the CW signal into the mic input of a handheld radio I've stripped down. The idea stems from this ...
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Relay is behaving differently from tutorial

Given: Raspberry Pi3 Sunfounder 2 channel relay plugged into 3.3v plugged into ground plugged into pin 18 import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.OUT) GPIO....
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253 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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214 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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Scaling down Raspbian for Adafruit PiTFT 1.14"

I want to use the Adafruit PiTFT (click here) 1.14" with the Raspbian Desktop. How can I scale the Raspbian Desktop down so that it will be normally sized on the 240x135 px screen? An example with ...
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GPIO Power off on shutdown with retropie

i asked this question before but i have added a diagram to explain it more clearly. I am building a retropie arcade machine with a raspberry pi. I have added a shutdown / startup button to shutdown ...
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71 views

Detecting Voltage With a Raspberry Pi

I want to use a Raspberry Pi to detect whether a generator has started. I had planned to hook a 5V power supply to 1 of the 240V legs on the generator and then run that through a 3.3V voltage ...
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537 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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304 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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2answers
380 views

Rpi3B SSD1306 OLED I2C Interface Problem

I know there are similar questions, but none of them helped me out. I have a Raspberry Pi 3 Model B Rev 1.2 and Raspbian 10 installed. I try to connect an 0.91" Oled display (Hardware Details) which ...
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1answer
2k 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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PWM input in Raspberry Pi

Is there a way to read a PWM signal from the pins on Raspberry Pi? I tried googling it, but I only found PWM output, and not input.
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504 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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How to get AIY voice project to shutdown with button

Greetings fellow raspberry pi fans! I use this code for AIY VOICE KIT google assistant. This kit uses a raspberry pi to run google assistant. So basicly you can build your own google home and control ...
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259 views

How can Rpi use a matrix key pad to read multiple, up to 256 keys / buttons?

I would like to build an organ pedal board and use Raspberry Pi as signal processor. The pedal board will have 32 inputs, one for each key. I am planning to use magnetic sensors (like A3144), which, ...
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278 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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302 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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1answer
259 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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37 views

Using a GPIO pin as output and input

Good morning everyone, i'm working in a project that involves having an state pin and button detection. The escenario is the following: when raspberry pi finish booting, a pin is pulled HIGH (this ...
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30 views

How to cut power to gpio pins on shutdown

I am working on a project where i am using a pi running retropie to make a homemade arcade machine. i have wired and coded a startup/shutdown button. i would like to set up the pi n such a way i can ...
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1answer
20 views

Raspberry Pi fan does not turn on using Python

I'm trying to make my case fan turn on using Python code. I have connected the fan to the GPIO 4 pin and the ground pin. The code I'm using is below: import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) ...
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349 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
272 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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472 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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Using RPI to control analogue VIDEX intercom system

I'm getting to grips with Python and RPI with the view to replacing one of the VIDEX 3311 intercoms at my workspace with an RPI device to answer the buzzer, see who's at the door (using extant systems)...
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287 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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318 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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Raspberry pi 0 - openocd debugging “jtag scan chain interrogation failed: all zeroes” and “already exported” problem

I am trying to install openWRT on a router using my Raspberry Pi Zero. I am following the exact steps as explained in http://www.alfredklomp.com/technology/experia-v8/ However, for some reason I keep ...
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28 views

Run Python RPi.GPIO as sudo

I'm trying to use the RPi.GPIO Library in a python-script with root-privileges. I essentially need to run it with sudo because other stuff in my script require root-privileges. When i try the ...
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11k views

How fast can GPIO pins toggle?

I'm currently using Python's RPi.GPIO module to toggle some pins, and I want to know how quickly it can do this. I need the pins to be toggled on the schedule of a ~50 mhz FPGA clock, which I'm ...

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