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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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Daisy Chaining Two Raspberry Pi 3b+ to have double GPIO pins?

I am trying to figure out the plausibility of connecting 2 Rpis together in order to take advantage of the additional GPIO pins and have synchronized output between both pis. I realize there are other ...
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connect sim800 with rpi3 model B

I need to connect a sim800 module to a raspberry pi 3b+ using gpio. Do I need to use an FTDI cable or is jumper cable enough?
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Can I used a Raspberry Pi as a source of PAM8403 Power Audio Amplifier Module

I have a project that use text-to-speech in Raspberry Pi, I buy a power amplifier in Shopee (online shop). The power amplifier module used PAM8403 and it need a 5V to use it. I want to connect it to ...
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1answer
30 views

How can I change the value of GPIO4 form 0 to 1?

I want to change the value of GPIO4 form 0 to 1. But I can't. The procedure of my typing is below~ Please help me. My hardware is Raspberrypi 3 B+ model. ============================================...
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1answer
22 views

Pi GPIO over network to another Pi

Can you send alarm GPIO output from Pi to another Pi GPIO input over internet? Example: connecting door contacts to GPIO input of a Pi and play siren at remote location over internet to another Pi.
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2answers
24 views

gpio-shutdown doesn't seem to have an effect

We are trying to have the Pi shut down gracefully when power is removed. We have a battery connected so that it will have time to shut down. So far, our attempts to use gpio-shutdown have been ...
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27 views

I2S Recording combined with I2S Playback

I have a Raspberry Pi Zero and I am using the Adafruit I2S MEMS Microphone together with the ADAFRUIT I2S 3W CLASS D AMPLIFIER BREAKOUT - MAX98357A. I did follow the two respective tutorials and I ...
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1answer
19 views

Node-Red does not turn off the relay

In Node-Red, whenever I put a single status type for reading the GPIO status or GPIO in/out in the flow, it turns on the relay. I cannot turn of it by injecting 0 value as string. When I delete all ...
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3answers
46 views

Pi Zero Button pressed detected incorrectly

simulate this circuit – Schematic created using CircuitLab I have a script that sends me a firebase notification when the doorbell is pressed. It was working fine when it was on the breadboard. ...
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0answers
13 views

Waveshare GSM/GPRS/GNSS HAT not connecting to Cellular network

I have this HAT i bought for a pi project I am working on. I get the device to power on, I can connect via USB from PC, and can connect from pi too. However, the NET LED just blinks every second, ...
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1answer
40 views

Accessing RJ45 pins individually from Raspberry

I bought a small optical monitor sensor. It basically detects optical pulses from an electrical meter and then triggers an ISR on a datalogger, which is a concrete product for this purpose. Because of ...
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1answer
32 views

How do you use both USB Serial Gadget and UART on Pi Zero?

Just like the title says, I want to use both the GPIO UART and the USB Gadget at the same time. Background: I've been working on modding up one of the Adafruit IoT printer projects, which uses the pi ...
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2answers
33 views

What is the easist way to connect a switch button to the GPIO pins?

I am trying to up my pi skills on working with hardware. I would like to connect a few buttons to my gpio pins. I have seen various ways to do so and want to know the simplest non-permanant way. I've ...
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2answers
24 views

Ground running back through logic shifter?

Sorry if this is a silly 'beginner' question, but I'm still only just getting into working with the Pi. I have a Pi Zero that I want to use to drive a module of a few WS2812 LEDs. Because the GPIO ...
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0answers
12 views

AdaFruit fona modem not working with raspberrypi 3B

I am trying to use an AdaFruit Fona modem with a RPI 3B using PPP. But i cannot communicate with the modem. The Fona is connected to the PI using the GPIO pins for serial connection, and the green LED ...
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Need to run a gpio high when audio playing

I'm fairly new to the raspberry pi, I am working on a smart mirror project with a Chromecast audio receiver. I am running raspbian stretch. I want to use a relay to turn on the audio when the pi ...
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57 views

How to Set Default GPIO Pin State for Boot

When booting the Pi the default pin state seems to be HIGH. Is there a document that I can edit that will change their default state to LOW?
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1answer
25 views

How to hookup pt100 with pi 3 without max31865 for temperature logging

Absolutely noon on pi here. I wanted to make a temperature logger with my raspberry Pi 3 and a "pt100 2 wire k type" thermocouple. I spent the evening googling about it and learned that one of the ...
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What are the other pins grouped witht he RUN pin on a raspberry pi (zero)? [duplicate]

On my raspberry pi zero, there is a group of four pins next to the gpio header, at the end with the camera connector. One of these is the RUN pin. What are the other three?
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1answer
19 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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54 views

Raspberry as I2C Slave, how to slow down transfer rate?

I have had minor success using the PIGPIO library and interfacing the Pi as an I2C Slave (Using GPIO Pins 18 and 19 as SDA and SCL) with a Campbell CR1000X Datalogger I am encountering a problem ...
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1answer
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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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0answers
27 views

What is (typically) GPIO's UART RXD input impedance in a RPi 3 Model B?

I'm sorry if this is a trivial (or already answered) question, but I really couldn't find an answer on the web. I'm trying to connect an AVR board, which operates at 5V, to a Raspberry Pi 3 Model B's ...
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1answer
54 views

Understanding the GPIO pins

I've not yet got into the GPIO pins. Can someone help me understand how they work? Are some of them special in some way? Do certain pins produce certain polarities or is that software defined? What ...
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Permission issue accessing /dev/mem – gpio node-rpio

I am somewhat of a newbie, so please let me know if there is a way I can go about this better. I'm working on doing some LED coding (WS8201 strip) with node.js and it appears I am having trouble ...
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2answers
93 views

Why does my circuit keep burning out Raspberry Pi pins?

I have a reed switch (actually several reed switches) that came pre-installed in my home as alarm sensors. When the 2 parts are together, the circuit is closed, when the 2 parts are apart, the ...
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1answer
16 views

Problem connecting AdaFruit PiTFT to RPi 3 using DuPont cables

I have a RPi 3 and the AdaFruit PiTFT 3.5”. I’m trying to connect the screen to the Pi using Pimoroni male to female jumper jerky cables (DuPont cables) because I want it to be further away from the ...
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1answer
33 views

Using other GPIO pins along with LIRC

I've been trying to create a voice activated IR Remote, using LIRC and a Respeaker 4 Mic Hat. Both are working perfectly individually. However, when I uncomment the line #dtoverlay=lirc-rpi,...
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1answer
35 views

GPIO interrupt detecting wrong values

I have a device which is based on Raspberry pi. It is known as ionoPi which is basically an i/o expansion board for Raspberry pi. I am writing a python script which detect signal change on input 16 ...
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41 views

eCompute Module - 2 Cams 1 Display not working

I'm trying to attach 2 SpyCams and an original 7" Raspberry Pi TouchScreen to a Compute Module 3 V1. I have two Compute Modules 3, a Compute Module IO Extension Board V3.0 and a Compute Module IO ...
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Read pin (power led) from port expander on ic2-0 at config.txt

In config.txt you can have conditional booting based on the GPIO pin level, e.g. the gpio4=1 line. Is it also possible to access the pin on the GPIO port extender at i2c-0, or is this something ...
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1answer
46 views

LED pwm fading is flickering

This is how I'm fading some LEDs using a logarithmic function. But with that the LEDs are flickering somehow. I don't understand why... import time import math import RPi.GPIO as GPIO GPIO.setmode(...
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3.5in TFT screen hat and Raspberry Pi 3+b

I'm trying to understand something about the MPI3508 screen I purchased (https://www.amazon.ca/dp/B07DQKQG6X). I tried powering it via usb and connected a PC in its HDMI input and got it working (the ...
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1answer
45 views

GPIO Pin connection with Game hat

I got a Raspberry Pi 1 B+, 2014 v1.2 board, and I was trying to attach it to Waveshare's Game hat The main issue which I have is, the raspberry board has 4 dead GPIO pins (tested using pigpio), 10,11,...
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1answer
29 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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1answer
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Why Raspbian jessie version 8 won't allow communication through GPIO serial pins?

I am running Raspbian Jessie 8 on Raspberry 3 and I followed the answer to the question Why my program won't communicate through ttyAMA0 on Raspbian(jessie)? But I still can't get my program to ...
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1answer
103 views

How do you control a 12V PC fan from a Raspberry Pi?

I just got an old PC fan from a computer that was taken apart at my school and I want to try and figure out how to make it turn on using the GPIO ports on a Raspberry Pi 3 Model B. It is a DC 12V fan ...
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2answers
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Multithreading/infinite loops affecting sensor values

I run a Python script on my RPi that manages all the sensors on the board and communicates with another machine using TCP sockets. The project gained in complexity and my script now has 5 threads ...
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1answer
86 views

How long to wait after shutdown to cut power

I am working a problem that seems to be fairly popular with the Raspberry Pi community. In essence, I am designing a circuit that will utilize a DS3231, a 555 timer, and a load switch to cut power ...
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1answer
27 views

Powering One Raspberry Pi Zero from Another

I'm trying to create a portable solution where two Pi Zeros are each running a camera module. I was thinking that I would use a single phone power bank. Is it advisable/possible to take 5 volts from ...
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1answer
33 views

drive LED and switch on same GPIO?

It seems like I should be able to ~abuse~ use the input pullups on the Pi to drive an LED, and that means the input is open so I can also sense a switch for occasional use. I can't talk myself into or ...
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51 views

Connect RunCam to raspberry pi

Just recently I got RunCam micro swift 3 (https://www.runcam.com/download/MicroSwift3-Manual.pdf) for computer vision project. However, I am struggling to understand how can I connect it to Raspberry ...
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94 views

How to use DS3231 RTC module on Android Things?

I use Raspberry pi 3 model B on Android Things. my situation https://stackoverflow.com/questions/51887326/when-boot-device-if-can-not-connect-to-the-network-how-to-set-current-time-on so, I bought ...
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0answers
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Clearing edge detect registers (GPEDS0/GPEDS1) crashes Raspbian Stretch

I've been working on a PHP library for Raspberry Pi for a few years now, and since (not sure specifically which) a version of Raspbian Stretch, the Pi becomes completely unresponsive when clearing the ...
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1answer
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Is there a way to use interrupt-driven GPIO input through the sysfs interface without a race condition?

I want to use the GPIO pins to wait for a button-press without using a CPU spin loop. My preferred way of using the GPIO pins is via the sysfs interface at /sys/class/gpio, but it seems to me that ...
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1answer
19 views

Multiple TTL sensors on serial RX GPIO 10

Is it possible to read more than one TTL sensor on serial RX GPIO 10? I know you can add multiple serial sensors on /dev/ttyUSBx Does the same apply to /dev/ttyAMAx ?
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RPi.GPIO - Properly Wiring and Setting Up Pins for Button Inputs

Edit: Breadboard, schematic, and code updated. I accidentally fried my Pi by shorting it out through the GPIO pins, so I figured it would be a good idea to ask for some help before trying my current ...
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1answer
40 views

How to cut the power on power pin 1 programmatically?

Is there a way to cut the power on power pin 1 on Raspberry Pi 3, using a command or force this on reboot?
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39 views

Raspberry Pi WiFi with GPIO Power

I am powering my RPI3 with 5V at the GPIO ports. The LED indicates that it is on, yet it does not connect to wifi automatically, or even power the wifi, as it does when I power it via micro USB. Is ...
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1answer
64 views

GPIO event handlers and inter-thread communication

I have a Python script using callback functions to react to GPIO events, as described here: https://sourceforge.net/p/raspberry-gpio-python/wiki/Inputs/ The description states that Python runs the ...