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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Connect screen to rasp

I have disassembled a virgin router that I had left over at home, and managed to get this screen out. I am wondering if it would be possible to connect it to the raspberry to show time or ...
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41 views

How to get RPi to generate a triangle wave, then outputting a PWM signal

I want my Raspberry Pi B+ Model to generate a triangle wave and output a PWM signal from one of the GPIO pins, but I'm not sure how to go about doing this. All I want it to do is add some small length ...
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9 views

I2C Gertduino + Raspberry

I am struggling to install the I2C properly. When I connect the rpi with the gertduino and set the jumpers for the atmega48p I only have two entries in the matrix from i2cdetect -y 1: 10b: UU 30b: ...
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1answer
15 views

Compiling WiringPi (GPIO input) into raspistill/raspivid

I want to synchronize a stereo camera for either stills or video. The goal is the smallest possible delay between GPIO trigger input and camera shutter actuation (so that stereo is possibly in sync) ...
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2answers
18 views

Can I use the output of one pin as VCC?

For a project I have to use a voltage level shifter. On both sides of this shifter I have to specify the target voltage. Thus my idea was to simply set one pin on high (3.3 V) and use that as VCC on ...
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34 views

Noob here, how can I rig up a button to the GPIO, and set it so that it will trigger a key press?

I'm quite new to the GPIO portion of the raspberry pi, and I am wondering how to rig up something that will detect button presses. I have a model b+ (40 pin). Which pins do I wire it to? How do I even ...
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15 views

Circuit advice for GPIO

I want to use the Raspberry Pi GPIO to control four mechanical relays. Since the output of the GPIO doesn't produce enough current to run the relays, I have devised a cicuit using transistors to ...
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1answer
9 views

pyspi and file descriptors

Has anyone else noticed that py-spidev seems to leave a file descriptor open? When I run lsof -p 5833 I see that my program has 5 file descriptors open, which seems fine. When I run sudo lsof -p 5833 ...
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30 views

Precautions to be taken while using the GPIO pins

As a newbie to the Raspberry Pi and electronics in general, I would like to start hacking around with the GPIO pins but any tutorial around the Internet warn me about frying the Pi one way or the ...
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1answer
24 views

How to drive nitinol (flexinol, muscle wire) through RPi

Is it possible to actuate muscle wire through Raspberry Pi ? This product expects ~200mA to revert to its original shape. If so, how would the circuit look like ? What resistors should I hookup ? ...
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25 views

Using GPIO pins for both touch screen and other GPIO operations at the same time

I would like to use a touch screen like this. As this is interfaced with GPIO pins, is it possible to use a ribbon cable and take out the pins onto a breadboard and use it for both touch screen and ...
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1answer
44 views

WiringPi Interrupt Problem

I'm trying to get interrupts working on the Raspberry Pi using the wiringPi library. When using INT_EDGE_RISING the code below results in very few interrupts when operating the button. This is ...
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23 views

Basic hand (touchless) gesture detection, solution needed

I need a good solution for basic gesture recognition (touchless), like swipe left, up, down, right, "tap" hardware/software for Raspberry Pi. I've seen http://www.hoverlabs.co/#hover which looks very ...
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38 views

GPIO communication between 2 Raspberry Pis?

I want to build a device with both a small screen and 4 digit display. I have been having trouble getting the 4 digit display to work with my model B+, but it works with the my model A, you can find ...
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11 views

Piface input pins as output with pifacecommon

I know it is possible to use the input pins on the piface as output pins. (src: https://projects.drogon.net/piface-abuse-using-inputs-as-outputs/) But how is this achieved using the pifacecommon ...
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1answer
42 views

RPI B+ with connected servo is twitching

I am looking for some advice on how to properly get my servo working correctly. I have wired it up and it appears to be working correctly. The problem I have is with the signalling causing a ...
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1answer
39 views

I2C and ST 24C64 (5V Problem)

I`m planning to use the 24C64 EEPROM with my Rasberry Pi. According to the datasheet the EEPROM "Single Supply Voltage" is 4.5 to 5.5 V. (Datasheet: ...
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1answer
67 views

What happened to the i2s pins which are in RPI B board and not in RPI B+ board

I'm working on RPI model B board.I've a driver for wolfson audio card,Which uses i2s pins for data transfer.Now i need to work on RPI B+ model.But there are no i2s pins in model B+.What i need to do ...
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Hardware power ON/OFF for USB

i just needed some further explanation of this question, exact same pictures with physical orientation of pins, what is needed to make a GPIO software controlled switch for usb power?
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1answer
28 views

Does the Raspberry Pi manage hardware interrupts?

I'm planning to use a raspberry pi to move DC motors using a PID programmed on the raspberry pi. the question is can I interrupt the raspberry pi by hardware, The idea is to interrupt it depending on ...
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22 views

GPIO pin PULL_DOWN would

I have set up a Arduino to send a 3.3V signal to my RPi if an object is detected in front of the UltraSonic sensor. I have measured the signal at 3.26V. But it does not work. Since the signal from ...
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57 views

Raspberry Pi Model B as FM radio receiver

I've got an idea- FM radio tuner on Pi, and it could be done with usb fm-receiver and any radio app, but Pi has a bad bug- with anything connected to usb, from usb-flash to usb powered hub, sometimes ...
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1answer
58 views

Interacting with a RJ11 “phone” / Hardware

I'd like to be able to interract with a piece of hardware which is able to be controlled by a standard phone line (and provide vocal metrics, ...) Let me stress that it is not a modem, nor has it ...
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1answer
44 views

[C++]Trying to control GPIO pins but I get a Device or Resource busy error. How can I stop Raspbian from hogging the GPIO?

I'm using a class that I found on github to control the GPIO pins. That class can be found here: https://github.com/halherta/RaspberryPi-GPIOClass-v2 From what I understand this class works by ...
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1answer
68 views

Control dc motor using GPIO.PWM problem

I'm trying to make a small remote controlled car with the raspberry pi and attached two small dc motors to it, using the L239D chip. When testing without the remote control (which is a simple android ...
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35 views

Simple Buttons with GPIO, not working

I' following this tutorial to have two buttons working with my Pi. The code I have is the same: import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(23, GPIO.IN, pull_up_down = GPIO.PUD_DOWN) ...
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31 views

Raspberry Pi Refuse to Set GPIO Value

I'm trying to use a 5V relay with my Raspberry Pi B (lastest revision) and my Pi refuses to set the value to 1 for the pin connected to my relay. I'm following this tutorial Steps to reproduce: $ ...
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23 views

gpio.add_event_detect runs callback without signal

I have got a Problem. I want to build a simple audio sampler triggerede by 8 relays. tehe relays are closed by 230v but just close a switch to either ground or v++ (3,3V). the problem is that even ...
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2answers
67 views

Is it possible to power a model B+ via the 5v pins on the GPIO header?

I'm making a powered daughter board to mount my B+ Pi on. Can I power the Pi entirely through the 5v pins on the GPIO header? More importantly, can I also supply reasonable currents to USB devices ...
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2answers
48 views

Control sensor: SainSmart TGS-2600

I've purchased a SainSmart TGS2600 Air Contaminants Sensor, but got no data sheet or the like. Does anybody know how to connect this breakout to the Pi?
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46 views

3528 SMD LED room decoration

I might buy a LED strip to decorate my room. My questions are: Will it be easy to use this strip with the Raspberry Pi? I also would like to be able to control the color/color shifts with my ...
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1answer
88 views

reading pin state whether it's input or output [RPi.GPIO]

Is it possible to read pin state (1 or 0) whether it's set as output or input without setting this with RPi.GPIO.setup(pin, GPIO.IN/GPIO.OUT)? I mean i can do this via command: gpio read 2 But ...
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183 views

Major trouble with nRF24L01+ controllers and the RF24 library

I've had a hellish last three days. All I've wanted to do is get an Arduino Uno and a Raspberry Pi B+ talking to eachother with these little guys, and after following many different tutorials, I've ...
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71 views

Can I use the GPIO while the Raspberry Pi is powered on?

Can I do anything with the GPIO pins/ breadboard connections while my pi is turned on? It would be awesome if I didnt have to shut it off every time I want to change something since I am just learning ...
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1answer
50 views

Emulate GPIO activity

I'm working on a project using GPIOs. I struggle to write some automated testing code. I would like to emulate activity on /sys/class/gpio/X/{direction,value}. Is there a way to achieve this? GPIO's ...
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31 views

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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14 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
47 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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24 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
51 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
65 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
103 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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37 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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3answers
181 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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27 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
54 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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34 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
52 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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52 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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34 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 ...