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 blink LED when a USB drive is attached?

I've managed to turn on a LED on the GPIO pin when i connect a USB drive. I've managed to turn it off as well when the USB drive is disconnected. Now i'm trying to get it to blink but having ...
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7 views

Looking for a reference sheet for both Raspberry Pi and electronics for a study gruop

I'm planning to start a robotics study group for children or adults new to both electronics, robotics and programming. I've collected some reference sheets for programming, but I can't find any good ...
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1answer
25 views

Best way to report all GPIO Interrupts?

So I am trying to figure out the best way of reporting all GPIO pin interrupts. My plan is to capture the high and low interrupts and post that to a URL. I haven't found many resources except for ...
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8 views

SSH reverse tunnel, how does it work? Help setting it up

I've been experimenting with a raspberry pi, and I would like to do some home automation experiments with the gpio on the raspberry, but I would like it to be connected to the internet so I could read ...
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2answers
37 views

5.3V power source w/ 24kohm resistor

Let me start with mention that I don't know shit about electronics. I bought UBEC to power my RPI but it had output voltage of 5.3V so I decided to use 24kohm resistor to lower it down. Now voltage on ...
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1answer
27 views

16 channel relay for RPi

I'm still kind of new to the raspberry pi, but familiar with turning an LED on/off using the command line or a python webserver. I have a Model B Revision 2. I've been asked to do a project that ...
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1answer
73 views

Replacing a PC with a raspberry pi

I want to replace an old pc which were used for controlling some devices in our lab. For this purpose we need a small pc with at least 26 GPIO-ports and the ability to send the retrieved data over ...
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25 views

Is there a way to detect if a PiTFT display screen is connected?

I am trying to detect if a PiTFT screen is connected. Is there some kind of GPIO pin I can probe and detect it to some extent? Thanks
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2answers
49 views

Connecting B+ to Serial Port

I have a recording device with a 9 pin dsub connector for control. Pin 1 == Ground Pin 2 == TxD Pin 3 == RxD Pin 5 == S. Ground 4&6-9 == NC I'd like to use the 40pin header on a raspberry pi B+ ...
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23 views

Errors out with no explanation when trying to run a blinking light function in python

I have created a python script to press a button and have my light blink but it isn't working when I transported the function to my main script and it errors out with no information so I don't know ...
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2answers
39 views

My 3V relay doesn't work on GPIO but works on 5V pin with resistor

Ok, I have this awkward situation. I have a 3V relay that I need to implement in my project. When I connect it to a 5V pin on RPi, everything's working fine, I can hear the coil opening and current ...
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28 views

gpio /value file appears with wrong permissions momentarily

My son is implementing a server on a raspberry pi that allows control of the gpio pins via a network connection. He has discovered a very strange bug. First, the OS being used is raspbian, a version ...
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1answer
45 views

My Pi can boot but extremely hot. HELP!

After trying the GPIO, my PI cannot not boot. Few weeks later, the polyfuse seems recovered and it can be boot. But the CPU is very hot and reach 80C. The USB port is not work and the PI is ...
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38 views

Raspberry Pi GPIO Virtualization,Possible?

So i have (planned) a project that utilize the GPIO.From what i know GPIO can be programmed and sending or receiving digital I/O. But since i don't have enough fund (yet) i need to know is there any ...
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1answer
24 views

Defining PWM ports to be used on the GPIO

Now as i have noted in previous questions i understand the PWM area of the raspberry pi is the most saturated area, but my question lies in which ports can actually be allocated as a PWM output due to ...
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2answers
64 views

How can I exit a while loop at any time during the loop?

I have a python program that loops through some GPIO commands. How can I break the loop at any time during the loop by pressing the Enter key. So far I have this... import sys import select import os ...
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1answer
50 views

How to measure mains frequency safely via GPIO

I would like to measure the mains power (120vac/60hz) to know precisely when the voltage drops to 0, but in a safe manner for the pi - one solution would be to use a high-value resistor bridge that ...
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1answer
65 views

what is the best way to let website users control devices on the pi?

I have a simple robot I am working on. There is a webpage, using arrows to navigate, and a streaming webcam. Ive been reading, that using exec(command) is insecure. Unfortunately, I dont know how to ...
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36 views

Control a 2004 display - with or without IIC/I2C serial interface

I ordered a cheap 2004-LCD-display and a I2C serial interface to use it with this display and connect it to my raspberry pi (model B, rev. 2) running raspbian. Until both arrives, I have to decide if ...
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1answer
67 views

Control liquid solenoid valve with raspberry pi and RTK-000-001

I'd first like to say that i'm a complete noob when it comes to electronical stuff. Im trying to make an automatic water gardner with a Raspberry pi. I found this solenoid valve to control whether ...
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2answers
103 views

Connecting two cameras into a PI

Is it possible? One connects to the CSI port and the other one to the GPIO ports and use the i2c interface to extract the data.
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1answer
27 views

Needs some ideas to trigger silicone rubber buttons

I would like to remote control the HVAC in the house. As a first not so intrusion attempt (rather than install relay and everything), I'm thinking to attach some GPIO pins to the controller panel and ...
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3answers
136 views

Connecting a garage door opener remote directly to Raspberry Pi

I am a newbie. I am going to try and make my first Raspberry Pi project. I have the Model B revision 2.0 board and want to connect a spare garage door opener remote. I have an option of using a relay ...
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43 views

GPIO pins are not working

I have connected the LED as shown in picture below on GPIO #18: And I ran following program: import RPi.GPIO as GPIO, time GPIO.setmode(GPIO.BCM) GREEN_LED = 18 GPIO.setup(GREEN_LED, GPIO.OUT) ...
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36 views

Raspberry pi and Arduino mini 05 connection

First of, I consider myself a real newbie when it comes to electronics and have my base knowledge in high level programing. So please have that in consideration in your answers. I have a raspberry pi ...
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55 views

Wired external trigger (remote shutter) for camera via GPIO

Say I have 2 Raspberry Pis. I want to use a wired external trigger (also called remote shutter) to take a photo or start video capture. I read the camera module can be triggered via GPIO. I want to ...
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2answers
57 views

Can I use GPIO to close a circuit on a RC sender PCB?

I've got an RPi running my OpenRemote2 Controller and want to add some more devices to my arsenal of remote control. These devices are a set of 3 mains switches (for lamps) and a projector screen ...
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1answer
80 views

Reading HC-SR04 echo with wiringPiISR()

The following code works with the busy wait, but if I replace the while loop with a call to wiringPiISR() it always returns 0 for the distance. I also tried calling wiringPiISR() before raising the ...
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2answers
86 views

Powering a 24V 1A device

I've got a little project going where I want to hook up a load of sensors to my RPi (PH, Temp, Humidity, light etc. etc., a camera, and also power a 24v 1a DC device. I'm wondering if this is ...
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2answers
69 views

using the temperature command in a bash script to affect gpio

I have a led connected to a gpio pin using wiringpi, and I am trying to have it affected by the temperature reported by /opt/vc/bin/vcgencmd measure_temp I have this command in an executable file ...
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81 views

HTML Button onclick function()

I would like to seek help on my Web Control Interface - LED On and OFF button REST API. I just started node.js two weeks ago and manage to created a basic REST API. It manage to display mySQL database ...
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1answer
20 views

Need advise for Web Control REST LED Switch

I would like to seek for advise and help on REST API - Web Control Interface LED Switch. I been searching over the net and seems kinda lost, so I hope you guys could help me out with it as soon as ...
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1answer
81 views

Graphical Programming with WebGUI

I was wondering if there is any project that enables a user to write some simple IFTTT style programs for the Pi (or other Linux boards) that also breaks out the GPIOs of the Pi to be used in such a ...
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2answers
64 views

power on from idle with gpio3, undocumented?

reading this thread : http://raspberrypi.stackexchange.com/a/19659/19456 i found out that you can power on the rpi from idle by connecting gpio3 (pin5 revB) to ground, tested it and it works great. ...
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84 views

Pi as a USB client

I am looking for a way to have the Pi act as a USB client and masquerade as a flash drive. I have seen lots of suggestions, however most of them are old (1+ years) by now and vague/incomplete - I ...
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2answers
75 views

Hot plugging the GPIO cable

I just got a raspberry Pi, and I am more familiar with software than hardware. Can I plug my ribbon cable into the GPIO pins if my Pi is on?
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1answer
51 views

Need help in my LED Switch REST API [closed]

I would like to seek help on my LED Switch REST API. I have created my own REST API and able to light up my LED when I type in the URL for example: localhost:3030/7/1 to light on and ...
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2answers
217 views

RF24 communication with Arduino

I have been trying for ages to work this problem out and can't figure it out. I have two nrf24 transceivers, one connected to the raspberry pi and the other connected to an Arduino. My code for the ...
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2answers
56 views

how to access local GPIO from remote Django/apache server

how can i get a local event (example: a physical button pressed) to trigger events on a remote django website. without using a keyboard or mouse click. thanks
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1answer
56 views

Breadboarding: pins connection

I have bought a raspberry pi some time ago, and I have been written some code, but now I need to take use of the breadboarding material. I don't really understand how and where should I connect a ...
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112 views

Boot Problems sh: can't access tty: job control turned off

I had one of the rf24 transceivers connected directly to the pi using jumper cables and everything worked fine. then I bought a case and was forced to use a ribbon cable. With out the transceiver ...
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33 views

LED Printed Circuit for RPI

I have searched high and low for this but I have not been able to find anything close. Basically what I am looking for is a PCB which has a red and a green LED on it and already has the appropriate ...
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0answers
73 views

How to interface a Programmable Logic Controller (PLC) and Raspberry Pi?

I am currently doing a project in image processing using OpenCV and I will be cross compiling the program in Raspberry Pi and it has to communicate to a Programmable Logic Controller (PLC) for further ...
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1answer
47 views

Small display with no assembling

I'd like to buy a display for my pi (B+, I will by it as fast I can). But I can't find any options that does not require assembling. Display can be "anything", like character lcd ...
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27 views

Controlling ac home devices via gpio and relays is that hard?

Is it possible that I solder some relays into the elecrical switches in the house (in each one) and control each rooms devices with a raspberry pi (a rpi for each room)? I think I'll be needing a ...
0
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1answer
44 views

wiringPi interrupt not working

this program is supposed to blink led when I press button, but the led start blinking with the start of program and never stop. button wired to gpio 17 and ground (0 in wiringPi map) led wired to ...
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2answers
75 views

Error on displaying mySQL records in my REST API

I would like to seek help on my REST API. I have finished constructed my basic REST API for my Raspberry PI and able to work now, thanks to you guys. Now I would like to display mySQL database records ...
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3answers
166 views

PI4J: Multi-threading when listening to Pin Interrupt events

Currently I'm working on a application for my RPi which will be monitoring a set of GPIOs in real-time where the exact time when the GPIO turns HIGH is crucial for my application. The actual date is ...
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1answer
56 views

MCP3204 ADC with low sampling rate << 100kSps

I'm trying to read light value from an LED bilking very fast. So I choose TSL12S as a light sensor, and MCP3204 as an ADC. In datasheet, MCP3204 have sampling rate up to 100 kSps when Vdd = 5 V is ...
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1answer
31 views

powering a RPI with its circuit from one wallsocket

I want to power a RaspberryPi with 54 LEDs (24 white, 24 warm white, 6 RGB - probably all at 20mA or something like that) from one wall socket. I'm planning to use the Pi to control the LEDs via ...