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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Constant communication between raspberry pi and android device [on hold]

I am a newbie to raspberry pi and I looking to define a webservice that will make the consistent communication between raspberry pi and android application. I am using its GPIO to control the ...
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1answer
35 views

Need 1 more 5v Pin - what to do?

First off I have only very basics of electronic understanding, so I welcome any help that I can get. I use a Touchscreen on my Pi that occupies all 5V and 3.3V pins. I also want to use a 433 ...
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2answers
61 views

How to read Analog 5V sensor ouput with Digital 3.3V GPIO?

I bought the "Sunfounder Sensor Kit" for Raspberry Pi 2, but the whole content is made for Arduino (5V). I have bought ADC, Level Shifters but I am stuck because I think I certainly miss a simple ...
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1answer
13 views

Access the display from a python app running as a service

Problem: The code below can't access the display when running as a service. I have my raspi hooked up to a touch screen monitor in the kitchen and I've attached a Passive Infrared sensor to the ...
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1answer
86 views

Is it safe to leave stuff connected to the GPIO pins when the Pi is powered off?

I am asking about stuff that would be within the normal operating limits when the Pi is on, i.e. 3v3 level voltages at small currents, when the pi is shut down (but still powered), and also when the ...
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1answer
41 views

using GPIO Reading from 4 inputs give me non accurate output

I am trying to read from 4 inputs to get an integer value but when I test my code the actual value does not match the expected My Code: import RPi.GPIO as GPIO import os, time i=0 ...
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2answers
57 views

Plug a 5V fan to GPIO 1 and 2

Regarding to the following picture, I understand that I can plug a 5V Fan by plugging it in between pins 1 and 2? This is right? (+ on 1 and - on 2?) My need : Plug a 5V fan to run all the time ...
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1answer
30 views

Connect usb camera to gpio pins

Is there a way to connect usb camera to gpio pins? The reason doing so is the inconvenient location of usb ports, hence my custom box for raspberry pi needs to be expanded just for usb connectors. I ...
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9 views

Using GPIO pins as switch [closed]

I just bought a 12VDC solenoid style lock, and I have it wired to a breadboard with a switch, but I wanted to know how I would wire it to my Pi to use the Pi as a switch with Python. Are there any ...
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1answer
15 views

send gpio commands from rpi python script to another rpi

it is possible to control the Gpio of a raspberry pi connected by WiFi by another raspberry pi by a python script? I need to Connect\disconect some electric loads of my house switchboard, controled by ...
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1answer
83 views

Importing RPi.GPIO

I am just writing some code for a Raspberry Pi robotics project. Since I don't have a Pi set up as a workstation, I am using a Google Drive notepad to do write it in, which recognises Python syntax ...
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25 views

Controlling Stepper Motor Responding Strangely

I'm attempting to simply move a small stepper motor over GPIO using a Sparkfun Easy Driver. This Stepper motor is the one I'm attempting to use. I'm using similar code and configuration to that shown ...
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1answer
106 views

Hacking my alarm clock, how can I use it's built in display with my raspberry pi?

I'm looking into hacking my digital alarm clock to be able to control it with my Raspberry Pi A+. It has a typical 4 digit screen (7 segment) with two dots in between. The screen has a brand and ...
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1answer
30 views

wiringPiSetupSys - input pin state does not change

I try to port my GPIO project from quick2wire to WiringPi. My aim is to read the state of a photocell connected to pin 24 of my raspberry pi (model B, revision 2). My code (python 3) looks like this: ...
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58 views

Best way to use Raspberry Pi as a 5-drive NAS with RAID 5

What I've got: The 40-pin 528 MB B+ Raspberry Pi Five SATA hard disk drives 1) Is it best to use the four USB ports or find some kind of adapter for the 40-pin GPIO? 2) What do I need to ...
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1answer
24 views

Connect 2 different sensor to same ground

Can I connect 2 different sensors to same ground pin? Here's how I pictured it. Sensor1 and Sensor2 are ground of sensor 1 and 2.
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2answers
77 views

Why are some GPIO pins HIGH when the Raspbeery Pi boots up

I have an easy circuit wired up, with a LED connected to pin 18 on the BOARD reference. I run a simple program to put pin 18 to HIGH, which turns the LED on, and then a couple of seconds later, I set ...
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37 views

Specify interrupt in devicetree overlay

I have created a devicetree overlay to add an MRF24J40 transceiver to Raspberry Pi. The interface of the transceiver is SPI and an interrupt request. After some trouble the device finally appears in ...
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1answer
50 views

Not able to use Raspberry pi as a FM transmitter

I have refered to this video https://www.youtube.com/watch?v=6smyUoLugsg .The problem is, in it he has used a Raspberry pi (first model). I tried the things he told me but it wouldn't work. I urgently ...
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2answers
160 views

Connect GPIO output to second Pi input

Is it safe to connect GPIO output to GPIO input?? for example: Set the GPIO input to GPIO.PUD_UP and connect it to GPIO output. Then when the output is HIGH, then the input is logic 1, and when the ...
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1answer
57 views

PIGPIO stream pwm data over websockets with nodejs. GPIO

i use servoblaster, one of the first projects for PWM (pulse with modulation) on the raspberry pi. Now i got a new raspberry and i wanted to try the very promising pigpio. It looks really fast and ...
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1answer
52 views

How to query GPIO's value?

I am using raspberry pi B+ board. I have joined up an infrared sensor to GPIO 12. I want to use python to query this value, but I am getting "none" instead of a value. This is the code I am using: ...
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1answer
73 views

Safe shutdown button not working

I used the method described here and here , which is a python script based on interrupts, to enable safe shutdown via push-button press. These are the steps in short: 1- sudo nano test.py 2- and ...
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1answer
47 views

What would I use to let me use the GPIO pins on my RPi without soldering directly onto the pins & without a breadboard?

Is there a 'thing' that I can use to use the GPIO pins on my B+ without soldering and without a breadboard? I know I could use a breakout board with a ribbon cable and breadboard, but that adds an ...
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1answer
21 views

Setting PN532 operating mode

How do you set operating mode of PN532 NFC reader/writer? Tutorial on ITEAD PN532 states which codes should be used to set system into I2C (SET0=1 SET1=0) and SPI (SET0=0 SET1=1) mode (default is ...
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1answer
42 views

GPIO ground on adafruit TFT hat screen

I recently got this hat screen for my B+. It has headers to use the GPIO pins that aren't used for the screen. The screen works well, but I want to make use of the other GPIO pins. The only problem ...
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Is this a bug in sysfs? - GPIO access control problems [duplicate]

Here's the code: #include <stdlib.h> #include <stdio.h> #include <sys/stat.h> #include <fcntl.h> int main(int argc, char** argv) { char buf[1024]; int fd = ...
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1answer
61 views

PiTFT tactile switch #17

I have been searching for clarification on PiTFT tactile switch, and folks have always been around #18 for backlight, and adafruit's tutorial requires to solder jumper 18 at the back of the board. I ...
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59 views

Can header pin 11 be used as GPIO17 in Windows 10 IoT?

I have an Energenie RF transmitter add-on board which fits onto the Raspberry Pi header (for more details, see https://energenie4u.co.uk/res/pdfs/ENER314%20UM.pdf). This board allows the Raspberry Pi ...
2
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1answer
53 views

Controlling servo with pi-blaster works but pi-blaster.js does not

I am able to control a servo with pi-blaster from the command line successfully. However when I try to use pi-blaster.js to do so in Node.js (either at the node command line or from within a Node ...
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3answers
674 views

Can I use the 3.3v pin instead of the 5v pin?

I am using a HC-SR04 ultrasonic sensors, and I don't have enough 5V pins on a Raspberry Pi, and I don't want to buy an expander. So is it possible to use the 3.3V pins on some of the sensors? What ...
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1answer
78 views

Raspberry Model B rev2 - fan controlled by relay [duplicate]

Following up from this thread : Raspberry pi Model B - Control a mini fan I found a relay switch that I had laying around... so I thought since I can control the relay with python, then why not ...
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2answers
50 views

Is Raspberry Pi 2 better than Raspberry Pi B+ for controlling RGB LEDs via software PWM

Is the Raspberry Pi 2 better at controlling RGB LEDs then then Raspberry Pi B+ due to it being faster? Reason why I think this is because when I control my RGB LEDs I notice they change colour (both ...
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GPIO23 (BCM) is busy when using /sys/class/gpio but I am able to use wiringPi pin 4 (GPIO23)

I'm having a bit of trouble accessing GPIO23 using /sys/class/gpio/. To clarify a few terms (according to the table on this page): Header pin 16 is BCM GPIO 23, which is wiringPi pin 4. Header pin ...
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2answers
95 views

Electronics of a water pump [duplicate]

So, I would like to connect a water pump to my Pi and programatically turn the pump on and off. I am looking at this pump: ...
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1answer
63 views

Off logic with Pi and Picamera using GPIO

Just trying to customize some Picamera functionality though this is my first time coding in Python. Basically I am using the GPIO with a button switch to essentially turn just the preview on and off. ...
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1answer
35 views

Retrieve printing data from old security system via DB25/LPT with Raspberry Pi [closed]

As a volunteer for a charity, I've been tasked with managing an old security system for the building. The security system outputs the security logs to an old dot matrix printer continuously. This has ...
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1answer
47 views

Measure the frequency of a 555 timer

I try to design a moisture sensor for the raspberry pi. To get a more stable measurement my idea was to use the 555 to generate a frequency depending on the capacitance. The circuit looks as follows: ...
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1answer
26 views

Output Pins not showing in Sensors

The ScratchGPIO package from Simplesi.net is a great addition to the Basic Scratch for Raspberry Pi Model 2 B++. When I downloaded the 5-15-2015 latest Raspbian image and V7 of Scratch GPIO, my ...
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2answers
51 views

Securing GPIO groups vs gpio-admin

The project I am working on right now requires a webserver and some server side code to access the gpio pins. I know that the pins require root access and I need to secure them before I open it up to ...
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1answer
51 views

Momentary switch as GPIO input - Trouble with code and bouncing/floating

Update So this is now the code I'm running. It now works but is bouncing/floating. - I believe this can be controlled within the code itself by looking for an edge value as opposed to a high or low, ...
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1answer
31 views

Available GPIO Pins for Transmitter

I have a touchscreen that uses the following GPIO pins on my B+: PIN NO. SYMBOL DESCRIPTION 1, 17 3.3V Power positive (3.3V power input) 2, 4 5V Power positive (5V power input) 3, 5, 7, ...
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1answer
98 views

Raspberry Pi multiple NFC readers

I am building a Raspberry Pi B+ powered survey device. It would use NFC scanners for multiple choice questions. It should display a question on LCD screen and the user should have his NFC tag scanned ...
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0answers
42 views

Alarm System - Detect 2.5V or 5V

I'm a newbee in raspberry and would like to add a raspberry on my home system alarm. I have 4 zones, and checked the voltage on the four cables: 2.5V when nothing is detected and 5V when motion is ...
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1answer
159 views

How to run 2 servos with wiringpi2 on Raspberry pi 2

Hello I want to use 2 servo with different gpio pins. But Raspberry has one hardware pwm (GPIO 18). first of all I tried another pin to run servo and my code: wiringpi.pinMode(18,2) ...
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5answers
141 views

GPIO Pin Explanation

My Pi 2 kit came with the following GPIO pin reference card. In addition to showing all of the 5V, 3.3V, GND, and GPIO pin numbers, it has additional information on some of the GPIO pins like TXD, ...
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82 views

kernel Disabling IRQ #49

I am using the RPi_GPIO library in a python shell to read a raw wireless signal using the wait_for_edge() function in a loop like so: while True: GPIO.wait_for_edge(26, GPIO.RISING) print 'R' ...
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0answers
10 views

Java Audiostream stops after X times

im working on a raspberry pi project. it runs java code, wich opens a wav file and plays it. when i press the button quickly a few times it doenst play the sound anymore. UPDATE: the ...
2
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1answer
64 views

GPIO protection diodes, maximum input current

I'd like to use the Pi to measure AC frequency, and to keep the circuit as simple as possible, I wonder how much abuse the GPIO pins will handle. PIC and AVR microcontrollers have protection on all ...
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3answers
68 views

GPIO Signals Over Long Wires

I did some searching and found a few topics related to this, but most seemed pretty old and I didn't get a clear answer. My hardware/circuits knowledge is pretty basic, so please bare with me. I have ...