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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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Use Python flask or NodeJS for controlling stepper motors via Web?

Im planing a project where I need to controll some stepper motors with my RaspberryPI. I'd like to controll those motors interactively via a web GUI. This server should run on my Py. Now I found a ...
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852 views

Just one GPIO pin stopped working - fixable?

I have tested all my GPIO pins in the past, and I know they all worked as outputs. Today I was using pins 11,13 and 15 (Board numbering), and they were all working fine, but suddenly pin 15 stopped ...
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26 views

Is it possible to revive GPIO 18 pin? [duplicate]

I guess it (pin 18) got burned after me accidentally connecting it to the 12V of the led strip and not the data pin, while the RPI ground and 12V ground were connected too. I used pigpiod, gpiotest ...
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46 views

GPIO only reaches 2,4v when high

TLDR; Under little load the GPIO 22 reaches 3,5v whereas under more load it only reaches ~2,4V, which is not enough to trigger the reset-line on an ATMEGA328P. UART GPIO Pins still reach 3,3V in both ...
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19 views

Emulate USB devices from one Pi zero to another Pi zero

I'm looking for the best way to emulate USB devices that are plugged into a Pi zero and connected to another Pi zero through GPIO pins, so the second Pi zero will emulate the actual device that is ...
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44k views

Multiple temperature sensors with a Raspberry Pi

I have seen plenty of examples for using one temperature sensor with the Raspberry Pi, however, how can I multiplex 5-6 temperature sensors to a Raspberry Pi? I want to read the temperature from ...
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19 views

How to connect a pulse sensor to my Raspberry PI 2?

I have a pulse sensor looking like this, having three outputs: _____ / \ | <3 | \_____/ | | | I assume it is the same model like sold on pulsesensor.com, but I bought it from an ...
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2answers
2k views

Can't turn on ACT LED on baremetal Pi3

I'm trying to run some bare-metal code on my raspi 3. This is my first time doing any sort of bare-metal programming, so first things first I want to turn on my ACT led as a kind of hello-world type ...
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2answers
3k views

How to change the Pin used for the 1-wire Bus

By default the header Pin Nr. 7 us used by the 1-wire kernel module. I would like to change it to a one of the 4 new GPIO Pins of an Rev 2 Pi.
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1answer
4k views

Getting a 1.44" TFT ILI9163C screen to work with SPI

I am working on getting my very very very cheap chines display working. As far as I can tell, its a TFT 1.44" 128x128 SPI display (printed on the board) - and the internet seems to direct me towards ...
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1answer
51 views

Ultrasonic sensor stops working a few minutes later

I want to get distance continuously using while loop but a few minutes later my code suddenly stops working and doesn't get distance (there is None value in distance variable) I have changed first ...
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32 views

5 volt GPIO pins on RPi not working?

So, today I made a simple LED circuit with a 5 volt pin on my Pi and it doesn't work. I tried the 3 volt ones and they work, but every 5 volt pin fails to work. The circuit just consists of a red Led,...
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1answer
153 views

Rpi3b+ to Rpi3b+ jtag/SWD connection and OpenOCD

I'd like to hook together two Raspberry pi 3b+ to use jtag/SWD with OpenOCD. I learned it can be done, but implementing it has proven challenging. I have two questions: How to connect the Rpi's. If I'...
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1answer
629 views

ili9488 Display Color Problem

I have bought 2 tft lcd from this link: https://www.aliexpress.com/snapshot/8378816373.html?orderId=79915084513225&productId=32610719676 and after implementing the codes in here : RPi 2 and 3.95 ...
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1answer
24 views

unwanted wake from halt

I want to use the "wake from halt" with my raspberry pi to keep it down must of the time and waking up using external stimuli when need. But I am not sure why, sometime it wakes up from halt although ...
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Sending Data from LoRa connected to Raspberry Pi

My objective is to connect a LoRa module with RPi and send data using it. So I made the connection:(Rpi to LoRa) 3v3 (Physical Pin 1) to Power Source (Pin 1) Tx (Physical Pin 8) to Rx (Pin 3) Rx (...
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Interrupts with MCP23017 using the mcp23017 dtoverlay

I'm at my wits end with this one. Okay, so we've got an MCP23017 with its INTA wired to the Pi gpio12 (bcm) in /boot/config.txt dtoverlay=mcp23017,addr=0x20,gpiopin=12 so far so good. I'm looking ...
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1answer
21 views

Connect Raspberry Pi to access controller Z-5R by GPIO

I try to understand how to control Z-5R. Z-5R - it's access controller, that control the electromagnetic lock by RFID cards. I want to control this device by Raspberry Pi. How I can plug it correct? ...
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1answer
473 views

How can I wire a Raspberry Pi to an 8-relay board in a tidy professional manner?

I want to connect a Raspberry Pi to an 8-relay board, such as this one. Together with ground and power this amounts to ten wires. One option to connect the two is by using female to female jumper ...
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1answer
18 views

Control GPIO from HDMI V sync

My Project on a Raspberry Pi 2 with Raspian stretch. I want use a GPIO pin to drive 3d shutter glasses (glasses hacked to receive 0 _3V square wave) Video playing on the HDMI port and A Pin goes on ...
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1answer
25 views

KY040 Rotary Encoder not responding at all

Hey I'm very new to raspberry pi and decided to start a mall project including a rotary encoder. I found some guides online that I followed but I just can't get any signal from the encoder ...
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1answer
27 views

MAX14830 GPIO control

I'm using the MAX14830 as UART and GPIO extender. Got the UART working, but I'm confused on how to use the GPIO. I notice there is a new entry in /sys/class/gpio (gpiochip496): pi@raspberrypi:/sys/...
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1answer
34 views

Setting a mode to a pin requires root permissions

I’m trying to change pin mode on RPI (with Raspbian) – it works when I invoke those commands sudo chown root.gpio /dev/gpiomem sudo chmod g+rw /dev/gpiomem but after every restart I have to execute ...
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35 views

How to toggle a 1 Channel Relay 5V

So. I have a 1 Channel 5V relay from a starter kit and I cant turn it on or off. I saw a bunch of tutorials but in every one the labels on the relay are such as VCC, GND and so on. My relay its ...
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2answers
64 views

Autostart a program comprising GPIO-commands

I am used to autostart with rc.local, after making my program called "test3.py" executable (sudo chmod a+x test3.py). I failed to get it autostarted, means as the first program which the Raspi-stretch ...
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1answer
40 views

Need to turn on a relay for a calculated length of time

I thought I was too old to appreciate the power of the Pi so pushing 60 I decided to educate myself :-(. What I need to do is to run a micropump (6V DC) on demand for as long as needed depending on a ...
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2answers
37 views

Closing Circuit versus voltage

I want to control this remote in the picture using GPIO. Am Newbie. I followed a cookbook to connecting the relay directly to the garage door motor but thought "Why not use the remote and perhaps ...
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0answers
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PiCamera Minimal latency between real world event and digital data presence

Using a picamera, what is the best latency one can achieve from a real world event like an led lighting up and the Pi/MCU 'knowing' it has occured(by extracting image data)? I would also be ...
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2answers
31 views

capture Image with picam then send to another pi via UART

I would like to send an image(JPEG) captured by a pi-zero (in a in-closed container) to an pi3 for storage and analysis. Currently I have UART via gpio set up, but so far I have only been able to send ...
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2answers
72 views

C Interrput every rsing edge 100kHz

i've a 100kHz signal and i want to detect every rising edge. I'm using ISR but edge isn't detected and when detected it's 46µs after the edeg. How to do? [EDIT] Here's the code with pigpio library: ...
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21 views

Would lifting the pads off of the display and camera connector kill a RP?

Tried to remove some I/O that i dont need from my RP3 A+ to fit in a mobile project. Ive done this before on my RP3 B with great success. But I wasnt to gentle when removing the display and camera ...
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42 views

What is the highest amount of relays Pi 3 can handle?

I'm looking to do something interesting with 16-20 laptop and computer fans. I was wondering if this was possible to just connect them to a large battery and then use a trigger to control some power ...
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1answer
28 views

How can i control the execution time of an engine?

I'm building a little Car with 2 Engine, one L298N driver and a Raspberry pi 3. But i need the engine run during some specific seconds and then cleanup the GPIO and the engine stop. Why? Because i'm ...
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49 views

How to get 3.5PiTFT and 2.8PiTFT to work on Raspbian Jessie 8?

Whenever I download Raspbian Jessie 8 and install it, it automatically works with 7inch display and a full up monitor through ribbon cable and HDMI cable respectively. However, when I plug in the 3....
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Blink project mishap, help?

So I've set up the blink experiment using my newly bought electronics kit for my RPi 3B+ (https://www.amazon.de/Freenove-Raspberry-Processing-Tutorials-Components/dp/B06VTH7L28/ref=sr_1_3?ie=UTF8&...
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534 views

Raspberry Pi Zero 433mhz transmitter fails but works on raspberry Pi 2

So I am using some 433mhz modules. I had them setup on my raspberry Pi2 and everything worked perfect. They could transmit and receive signals. I switched the entire configuration over to a raspberry ...
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23 views

Erratic motor behavior from a Pi being controlled through a websocket

I'm in the process of trying to put together a small "robot" that can be controlled over the internet. I'm trying to get the code for the drive motor controls down now, and I've hit an odd issue. ...
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3answers
74 views

Using special pins as gpio

I would like to use I2C and SPI pins as a gpio on my raspberry pi zero w. To be more clear, BCM 3-5-7-11-13-14 pins on the link [1]. I want to disable I2C1, GPCLK0, SPI0, UART, PWM0. Is it possible ...
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1answer
29 views

My rotary encoder is missing pulses - what are some potential solutions?

I have a rotary encoder with a very high resolution (5000 pulses per rotation). I used what I believe to be a fairly optimized rotary pulse counter program written in C found here but the faster I ...
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1answer
25 views

GPIO.input(24) is coming back True when it shouldn't be (false button presses)

I have a button in a working circuit. Within sys/class/gpio/gpio24, value changes properly (it becomes 1 when pressed down, 0 otherwise). When I use GPIO.setup(24, GPIO.IN) within python, GPIO.input(...
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1answer
34 views

PiCameraNotRecording exception when trying out PIR script

So I was trying out this exact same script in this answer https://raspberrypi.stackexchange.com/a/46513 but when I tried to run it (for the second or third time) it gave me this exception: Exception ...
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2answers
199 views

I have a dust sensor and I need to take in a voltage from the GPIO pins

I recently got a Dust sensor from a company and it says that the voltage out corresponds to the concentration of dust in the air. How can I use the GPIO pins to get the voltage reading? The voltage ...
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1answer
37 views

Read from special pins?

I'd like to use some special pins like 5 (scl) and 12 (pcm_clk)as regular pins to read from them. I made a circuit as shown here: and setup all connected pins like this: GPIO.setup(pin, GPIO.IN, ...
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1answer
23 views

Use internal pull up resistors with the gpio-keys module in the device-tree

I have an external board with some buttons that are attached to gpio 20 and 21 which connects these pins to ground when pressed: simulate this circuit – Schematic created using CircuitLab I'd ...
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2answers
42 views

How to make a stand by button?

I am using an Raspberry Pi 3b and a 7 inch hdmi waveshare touchscreen that connects to rpi with a hdmi cable and a micro usb cable. I want to program a push button from GPIO pins to make the screen ...
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1answer
49 views

Lipo power: Powerboost versus Micro-Lipo charger

I'm a hardware newbie, wanting to power my RPi Zero via a Lipo battery, and also have the battery charge without removing it. There are many posts about this, but my question is more about two power ...
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1answer
54 views

counter with tkinter

Good evening: I speak from Colombia, the problem is that I am doing a project in which I must have an object counter that passes a sensor. Well, I hope I can explain myself: code1 works perfectly, ...
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48 views

Wiring Pi - BCM 20 works with a button, but not BCM 21 :-(

I have two switches (buttons). Red is connected to physical pin 38 (BCM 20) and green to physical pin 40 (BCM 21). I call wiringPiSetupGPIO() it returns 0. When I use pullUpDnControl(redSwitch, ...
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0answers
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Connecting a PIR and Relay Module to a Raspberry Pi causing 2 Minute False Alarms

I am building a small home automation system, and one node has a PIR to detect motion, and a Relay Module to control a 240v light with a Raspberry PI 3. The PIR is connected to 5v, and has a ...
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2answers
48 views

can I use SSH and GPIO UART simutaniously?

I am connected to my Raspberry PI 3 B+ running Raspbian through an SSH terminal, and I am trying to make an application that uses the UART through the GPIO. Whenever I try to open the port "/dev/...