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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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463 views

Convert GPIO to 5V Power output

Is there any way to use a normal GPIO pin as a 5V output pin? I am using a screen that prevent access to all power outputs, so I have only the normal GPIO pins and ground pins, not mentioning the ...
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1answer
97 views

WaveShare TFT 1.44 Buttons in /dev/input

I have: Which is absolutely ideal for the project i work on for my daughter. The problem however is that the buttons on the board have separate /dev/input/eventX files. Do you know if this can be '...
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1answer
73 views

Can I connect GPIO pin and ground to a PC motherboard power switch to turn it on/off

I would like to use RPi to connect a jumper cable from PC Motherboard power switch to a GPIO pin and Ground to be able to turn the PC On/Off automatically and remotely. Would it work and is it safe?
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31 views

Is there a way to find a script/program that already uses some of the GPIO pins?

It seems that GPIO 5 (pin 29) is used by another process: when starting my script I get "...channel already in use..." warning. Oscilloscope confirms that, because after a reboot, the pin is ...
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1answer
151 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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28 views

HC-SR501 Not working as expected

No matter what I do, I get tons of 'false positives'. Occasionally the thing settles down, but it seems the majority of time it's: registering some kind of movement for about 3 seconds waiting ...
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0answers
8 views

How many DS18B20 sensors can RaspberryPi3 GPIO4 can handle? [duplicate]

Are there any limits for handling sensors over GPIO4 ? If yes, how many DS18B20 sensors can RaspberryPi3 GPIO4 handle?
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44 views

My PIR sensor watch() not invoke

I installed nodejs on my raspberry pi 3 model B v2. Then I connected PIR sensor using onoff (gpio module for nodejs) module. The problem is when I connect the power cable to the sensor if block ...
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41 views

Is there a python coding method for reading the value of a GPIO pin

Recently I have been learning to prototype circuits on a couple devices, as I am inspired to one day design and develop embedded systems. The two devices that I have been prototyping with are the AVR ...
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1answer
114 views

GPIO Input Not Detected Within While Loop

Hi I'm having a problem with trying to detect GPIO input on a PIN within a while loop. Turnstile B Entry button is what I am troubleshooting the statement if tsB_entry_button == False: import RPi....
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2answers
70 views

Controlling 12 RGB LEDs (with adjustable colour mix), with long cable runs

I need some advise on this -- driving 12 RGB leds individually. I was thinking of this model: LL-509RGBC2E-006. If I use these "plain" RGB LEDs with 4 pins, so that would mean I need to set 12 x 3 = ...
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161 views

GPIO mode in another file B different from the file A

I face a problem. File B has import from gpiozero which controls LED. The default GPIO mode is a BCM. While in file A, it allows NFC reader to read card which imports MFRC522. However, MFRC522 gpio ...
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1answer
46 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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1answer
70 views

Speeding up updating of GPIO pins

I have a program where each step, two GPIO pins have their duty cycle updated (I'm using pigpio). I'm running the program for millions of steps (think 50 to 100 million) and running the PWM outputs ...
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1answer
139 views

Force Sensing Resistor with Raspberry Pi

I have a school project where I have to make a car park with a fully functional parking lot checking system. The FSRs job is to detect any weight and send a signal to the raspberry pi that the ...
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59 views

Decoding a 74HC595 Shift Register bus with GPIO

I'm trying to decode an existing serial Bus communication used to drive 74HC595 (Shift register). 74HC595 Bus lines are: Latch : (When falling edge data are acquireq by the shift register, when ...
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1answer
118 views

Triggering Peristaltic Pump with GPIO

This seems really basic but I've tried googling many different ways and can't seem to find the right answer, so I'm sorry for what may be a tired question, but: How can I mimic a footswitch press ...
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1answer
138 views

Serial communication using GPIO Pins for more than 2 raspberries

I'm doing a project at work which involves multiple (more than 2!) raspberry pies (Model 3 B+) being able to talk to each other (talk to each other means being able to send data of the size of a ...
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0answers
73 views

AMS Franklin AS3935 Lightning Sensor can't detect linghtning

I'm using Embedded Adventures MOD-1016 with AMS Franklin AS3935 connected by I2C. The code is from pcfens/RaspberryPi-AS3935 as in given there example. Everything looks OK. No bugs, noises and ...
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0answers
37 views

HTTPServer / FTPServer loop colliding with callback thread

I am building an alarm application. I have a few PIR sensors and webcams. The application contains a webserver I use to manage the alarm from a mobile application done with kivy.The webcams upload ...
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2answers
2k views

What is the purpose of Raspberry Pi3 B+ 4 POE pins?

Good they to all devs or people with raspberry pi 3 b+ have you noticce the 4 POE pins in the board near the 4 usb ports? what is the purpose of that 4 pins? can I use that pin to power up my 5v DC ...
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0answers
169 views

Raspberry as FXO [closed]

So I was thinking to build my own voip system for my home. I've got a landline coming to my house. I was researching FXO cards and found out that they are really expensive so i'm thinking if i can ...
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23 views

Trouble running RPi cmd commands in Java

To test my program, I was trying to run the shutdown command. I tried using a ProcessBuilder to just run the command: ProcessBuilder builder = new ProcessBuilder("shutdown"); builder....
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2answers
341 views

Rpi Zero W ( not Rpi 2,3 ) - power consumption, idle and GPIO operate [duplicate]

Spec wise - all raspberries require 5v 2A input. My project needs multiple remote rpi’s to send periodical status of GPIO using python script ( runs on Raspbian Strech Lite ). Is a 2A a must ?
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1answer
96 views

How to Send Data From Pulse Sensor Wirelessly to GPIO Pins?

I am following this tutorial: https://tutorials-raspberrypi.com/raspberry-pi-heartbeat-pulse-measuring/. But I would like to implement the sensor in a watch. Is there an accessory that can fit in my ...
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2answers
161 views

GPIO Voltage detection [duplicate]

I have a device that is running on a Pi Zero W. I have another device that outputs 3.5 volts from a pin and I would like to use the Pi to detect if the devices is on or off. Is there a way to send ...
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1answer
188 views

GPIO Voltage tolerance for input

I don't managed to find the input tolerance on I/O pins, especially on the Input pins. If I apply a voltage 3,6v (3.3v +0.3) on an input will it be dangerous or is it ok ? If somebody have a technical ...
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3answers
140 views

Control power of other 5V devices using RPi GPIOs

I want to control the power-wire of another 5V powered device (s) using RPi GPIO. Potentially it will 8-10 of such devices, which I want to control. Each device needs 2-5 A (for example, strong LED ...
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0answers
88 views

4x4 Matrix keypad in c#

How do I get a 4x4 matrix keypad to work in Windows 10 IoT c# on a Pi3? I just need some help coding I have it all connected. It uses 8 GPIO pins
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1answer
855 views

Cloning RFID tags with Raspberry Pi 3 and RC522?

I've looked around a lot now and can barely find any information on how to clone RFID tags with the Raspberry Pi, I've seen plenty of content on how to do it using an Arduino but I would really rather ...
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1answer
92 views

Change Device Tree to pullup pin at boot

I trie to add a LTC2954 to the raspberry pi zero w. I designed and produced a prototype pcb with an lipo management system for load and loadsharing. My problem is, that the KILL Pin of the LTC2954 has ...
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2answers
268 views

Noise in the GPIO when output is high or low

I just set up my pi to run Homebridge allowing it to control an LED strip over GPIO pins, it all works well except the LED lights flicker with radio interference. This interference is very noticeable ...
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4answers
311 views

Dual power supply for Raspberry Pi 3

I am using a Raspberry Pi 3 B+. Now I want to power up my Pi through GPIO pin 2 or 4 using a LM2576, and it should also work with USB power supply from adapter. I want to know which supply is ...
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1answer
306 views

Wiring setup for I2C communication for RPi slaves

Recently found out that using the pigpio library one can set the raspberry pi to be a slave in a bus setup with an arduino. Someone has even written some test code on the RPi forums which shows that a ...
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2answers
152 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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0answers
62 views

Single bit transfer from Arduino to RPi through gpio

Trying to send commands from an Arduino to the RPi through the GPIO PCM. I can't do it through the serial port as the port is connected to a computer and commanding the Arduino. I was planning to send ...
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2answers
367 views

Open/Close Sliding Gate Using Raspberry Pi and Python

This is my first Raspberry Pi project. I’m a bit of a noob at the Pi, Python and other types of programming languages, as well as circuits and such. I’m trying to open my sliding gate to the entrance ...
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3answers
474 views

GPIO relay signal cross turns to all relays staying on after Darlington added

I have 4 Sunfounder 2 channel relays 7 of which that I'm using to control some things on my aquarium. I suspect that I may have wired them up wrong somehow though. The behavior I'm seeing is as ...
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0answers
56 views

GPIO commands for contact sensor circuit

I have a simple circuit that goes to a garage door contact sensor then to a resistor then to an LED to show if the circuit is open or closed. I've confirmed that my wiring works with a power source - ...
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1answer
81 views

Pi 3 reboots when GPIO 13 is given 3V

simulate this circuit – Schematic created using CircuitLab I am taking the 3V from Pi and giving it to COM of a relay. The NO goes to GPIO 13 of the same Pi. I have a 120V line that triggers ...
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2answers
47 views

How Should I Go About Wiring A RPi to a 6.4volt RC Car?

I’m a total newb with electronics but know my way around Linux/Python just fine. I’ve read many tutorials but none of them cover using gpio to control a RC car control board and I’m wondering what I ...
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0answers
183 views

How to access Compute Module 3 bank 1 GPIO (28-45) in Windows IoT Core

We have graduated from our prototype on Raspberry Pi3 to a custom designed board using the Raspberry Pi Compute Module 3 Lite (CM3L). Now that the GPIO and peripheral devices have been verified with ...
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0answers
46 views

Pin on off engine javascript nodejs

I have a little engine linked at pin 1 and 3. How can I turn it on and off throught nodejs? Is there also a way to control how many volts are sent (to make the engine faster or slower)?
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1answer
39 views

Raspberry Pi3 using different ground pins for multi ldr toy car

I am working on a toy car which is following the "light" and I am totally new at raspberry pi and circuits. In this video, he is using 1 ldr. I need 3-4 ldr to turn the car to left or right. (I am ...
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1answer
196 views

Fail to run Remote GPIO code from a PC using python3

I'm trying to run a remote GPIO code from a Linux machine to operate on RPI3. Code is running OK on another RPI3 to control each other, but when trying to do so from a PC, it fails. I followed the ...
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1answer
42 views

rpi BMC power/reset trigger with GPIO

i m thinking about building a BMC using a raspberry. So i need to simulate power and reset button press using the GPIO. I would like to know if a transistor is suitable for this application and if ...
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1answer
217 views

How to wire an HC-SR04 without a breadboard?

I have a Raspberry Pi and a HC-SR04 integrated circuit for measuring distance. I have found many resources for how to connect the HC-SR04 to the GPIO of the Raspberry Pi, but because the HC-SR04 ...
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5answers
75 views

Connecting 5V / 2A DC adapter positive line to GPIO

I have a working DIY UPS for my Raspberry PI 3B board. My requirement is that whenever the main power goes off the PI, the software should be able to detect it and immediately trigger a graceful ...
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2answers
318 views

Potentially fried raspberry pi

I tried to power the raspberry pi though the GPIO pins. I had a 3.7 volt battery charging board that outputed 4.2 volts. I connected it to 5v and ground on the raspberry pi and the lights were a ...
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0answers
91 views

Remote GPIO Control Help

Detailed Storyline Of What I Am Trying To Do: I have two raspberry pis, RaspiA and RaspiB. I want to control the GPIOs of RaspiB remotely from RaspiA. I followed the instructions from http://...