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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cron job for gpio 1-wire sensor fails at 17 minutes past hour

I am developing on a Pi 1B some work with 1-wire sensors - using my own software. My application is running as compiled C - bit-banging the GPIO. On the current setup I have a single sensor on gpio 17 ...
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1answer
22 views

RPi.GPIO error: Name error: RPi

When testing my code on my RPi 2 B, I come along a name 'RPI' is not defined error. Can someone please help me to figure out why this is happening? from PIL import Image import os, sys import ...
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9 views

wrapping GPIO.add_event_detect into a try except stops it from running

I have a basic system with a normally closed switch I need to monitor. If I run the program with the following setup, it works: if __name__ == '__main__': print("waiting for redunancy trigger") ...
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26 views

Pifox on rasberry pi 2

The rasberry pi 2 is well known to be able to transmit low power radio emissions off of the GPIO pins. I am a licensed amateur radio operator, and am trying to use the program pifox, a foxhunt ...
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1answer
38 views

how to implemment this metal detector code [on hold]

hi i am trying to build a special type of metal detector called a constant current metal detector. i need to use 7 gpio's to and turn some on transistors and some off in a repeating pattern. i will ...
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12 views

Controlling brushless motor with ESC and Raspbery Pi b+

I'm trying to build a quadcopter and I have one ESC, one brushless motor and one Raspberry Pi B+. I find many tutorials on internet to see how to connect these components but it doesn't work. I'm ...
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14 views

Permission Denied Exception on Raspberry Pi-2.While accessing the gpio pins using java servlet web application [duplicate]

Permission Denied Exception on Raspberry Pi-2.While accessing the gpio pins using pi4j java library in servlet web application which is running on tomcat We have developed the Basic Servlet web ...
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10 views

Rasperry PI GPIO/Camera Script doens't work as desired-Python

I'm making a timed Photo/Video function for the raspberry with a button and a few LEDs attached to GPIO. When pressed long the button should call the video function. This and the photo scripts ...
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2answers
38 views

Increase raspberry pi voltage

Say I bought you a RC car as a gift, that works on 24v battery. You decided that RC car is boring and want to control it with raspberry pi 2. There are two motors on the car. You bought a voltage ...
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24 views

Recording a wav file using a GPIO Microphone sensor

I have connected an analog sound sensor to my raspberry pi via an Analog-To-Digital-Convertor (MCP3002), a breadboard, and a whole bunch of wires (dupont cables). I have successfully tested the ...
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1answer
28 views

using try-catch to catch gpio interrupts

Is it possible to interrupt a try-except code in python with gpio interrupt to generate exception? In the "try" part i'm openning a socket and use socket.serve_forever(). I want to make a hard-reboot ...
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19 views

How can I make the ITEAD PN532 work on the R-Pi via UART?

I have used the Adafruit PN532 before on the R-Pi (A and B+) via UART and it works just fine but I haven’t been able to make it work for the ITEAD. The ITEAD supports I2C, SPI and UART. On this link, ...
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4answers
259 views

What bare minimum knowledge should I know before working with hardware on the Raspberry Pi?

I already have a RaspberryPi2 - and I've used it in a number of very basic software projects (My background is primarily in software development), but I'm getting more ambitious and find myself ...
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1answer
28 views

Attached LEDs to GPIOs 18, 23, and 24, using JavaME 8. 18 and 24 work, but not 23. Why?

I'm new to Raspberry Pi and I have just figured out how to use Java to power LEDs. However, I cannot get GPIO 23 to work. This is my wiring setup. Here is the java code I am using to power the ...
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1answer
46 views

Counting (multiple) pulses on a pi

I have 4 pulses to count. They range from one pulse every few seconds, to one source that will pulse about 10 times a second- so none are stunningly fast. Best option? I've had luck using a gpio pin ...
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2answers
95 views

Why cleanup the GPIO pins?

When running a program in Python, why would I want the cleanup command when using the GPIO's?
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1answer
21 views

Apache server control Python script

I have a temperature sensor on my Raspberry Pi 2, I read the data with a python script. My question is how do I run that script on the Apache server (with a push of a button). Specifically how do I ...
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2answers
31 views

Can I re-use the GPIO pins that are driving an LCD display?

I want to ask if I connect the LCD display to the Raspberry Pi, the pins that the display uses to work, am I able to use them for other stuff? For example, to connect 433 MHz receiver and have the ...
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2answers
57 views

Programming servo - What to use?

So I just decided to start a small side project using the RPi to control 1 or 2 servos. At first, I thought this would just mean plugging the GPIO pins of the servo to the GPIO pins on the RPi, and ...
3
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1answer
88 views

Raspberry Pi 2 Smoke Detector Circuitry with MCP3008

I am working on a gas/fire detector project using a Raspberry Pi 2. I would like to gather input from the following sensors: Adafruit AM2302 (wired DHT22) temperature-humidity sensor MQ-2 Gas Sensor ...
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0answers
10 views

Is there a bluetooth device for distributing remote GPIO devices?

In a project I am working on, the distance between my Pi and the location of the various sensors is quite far (>20m), so I was wondering if anyone knows of a small bluetooth beacon-style device which ...
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1answer
51 views

dc motors not responding to gpio's

I have a question. I've attached dc motors to gpio's and after running python program it won't turn. Attaching LED's would make them light very low. Attaching both of them to pin 1 or pin 2 would make ...
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1answer
26 views

is it possible to control 6v dc motors with pi

Is it possible to control FOUR dc motors with raspberry pi at the same time? If so, where can i find info on how can this be done (from the physical aspect)? Thanks.
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1answer
16 views

Resistors vs. Jumper Wired

I'm trying to connect a PIR motion sensor. In the tutorials I've found, I've seen people connect it to the Pi's GPIO using either a breadboard and resistors, or direct to GPIO pins using jumper wires. ...
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1answer
51 views

making GPIO 5V tolerant

Okay so I just accidentally bought a MCP23017 instead of MCP23018(this one is 5V tolerant) I don't have time to buy this one, because shipping to my country is painfully slow. Will be simple voltage ...
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1answer
30 views

Is there a way to connect an I2C RTC using pins 17,19,21,23,25?

I've been looking at I2C RTC modules like this one, but they all appear to be normally connected to pins 1,3,5,7,9. However, I'd also like to try to use a RaZberry Z-wave module on the same Rasberry ...
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0answers
45 views

Pluging an Adafruit touchscreen on a HifiBerry DAC+

I'm trying to connect a Adafruit PiTFT 2.8" TFT 320x240+ touchscreen and a HifiBerry DAC+ on a Raspberry Pi 2 B. Is it possible? Do I need to solder the touchscreen card on the DAC+?
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1answer
38 views

Getting my first TWI program working?

I am new with Raspberry and frankly didn't do programmation for 20 years. I am learning Python pretty fast and also acquired the PI2 and the HTU21D-F I was under the impression this was an easy ...
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2answers
40 views

Raspberry Pi jumper

This is a strange question, but I just want to see if it's possible. Basically, would I be able to safely connect the 3.3 or 5v cable to another GPIO pin as a sort of jumper? So for example, if if ...
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1answer
63 views

How to read Wiegand card ID?

I need a simple script that outputs ID of presented card in console. I tried a lot of opensource code that based on WiringPi library, e.g. Pidoorman, its forks by Kyle Mallory and E.J. Dyksen, RFID ...
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1answer
46 views

GPIO - RuntimeWarning: This channel already in use, continuing anyway

I was trying to run a motor using the Pi. It was working fine before when I was executing using a Python script. Later I installed WiringPi and tried to execute the GPIO using shell script and it ...
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4answers
93 views

Is it possible to shut off a Raspberry Pi 2 b using the GPIO pins?

I know there are plenty of guides out there for making a switch that uses the GPIO pins to shut down the Pi, but all of them use quite a lot of circuitry, but what I want is to just put a paper clip ...
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28 views

If I use a ribbon cable with my PiTFT, is there a maximum length?

If I wish to detach my PiTFT screen from my Raspberry Pi (Model B) using a ribbon cable, is there a maximum length of cable I can use to prevent latency issues with the screen? I saw in the PiTFT ...
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1answer
30 views

GPIO HW PWM @ 143Hz and 20-80% duty cycle, with WiringPi's gpio utility

I've tried to find the solution from other threads but they all seem to miss the point to a certain degree, usually going into kHz and MHz, or into the SW GPIO territory that I don't need. I have a ...
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2answers
49 views

How many buttons at once?

I own Raspberry Pi 2 B and I wanted to create something like Novation's Launchpad. How many buttons can I connect through GPIO at once?
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3answers
49 views

SPI library installation error

I want to read and write RC522 RFID by using raspberry pi. For that I want configure SPI communication. First I enable SPI in raspi.config. After that I tried to download SPI-Py package to enable SPI ...
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1answer
222 views

Controlling Servos with a Raspberry Pi

I am not sure if this will break my Pi, so I decided to double check In this image is a simple servo connection, I am still learning how servos work. I actually have two questions: If I decided ...
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0answers
18 views

GPIO Tripping Relay Without Setting Output

I have a simple circuit set up with a GPIO pin connected to a relay and a LED connected to the other side of the relay. The light is off normally, when I do GPIO.setup(23, GPIO.OUT) in the code the ...
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1answer
41 views

PHP controlling my led control script. Can't get it to work

I have made a very small script for my raspberry pi where I turn on the LED. import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(21,GPIO.OUT) GPIO.output(21,1) time.sleep(5) ...
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31 views

Control the inclinometer with RS232 or UART

I have bought an inclinometer today to try some things. Inclinometer has two communication port; RS232 and UART. Which one should I select? Actually I tried both but none of them worked. I have ...
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27 views

Controlling many stepper motors (not necessarily simulataneously)?

I would like to have an array of N stepper motors, and "step" a subset of this array once per second. Being completely simultaneous is not a requirement as long as any subset (from 1 to N, averaging ...
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1answer
63 views

Raspberry Pi and iMac display

A customer at my work has donated us a iMac G5 because it didn't do anything. We want to test if the display is still working, but I'm not sure if it will work. Does someone know if it is possible to ...
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2answers
122 views

PHP or jquery to execute python scripts for GPIO

I want to use php or jquery to control gpio pins on my raspberry pi 2. I have apache installed. When i execute python files using LXTerminal, they work fine. I have made the .py files executable and ...
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0answers
41 views

How do you use GPIO output with RPi and Google Coder?

I am trying to set up the "Blinky Lights" project with Google Coder v0.9. I have used the code from the example project, unaltered, as well as setting up my breadboard exactly as the instructions ...
0
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1answer
56 views

How do you decide between communication protocols? [closed]

I'm experimenting with using the raspberry pi as well as an FPGA, and I want to try making some program that runs on the pi but uses the FPGA for processing. When looking at the pi output pins I ...
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3answers
294 views

Powering Pi from Ni-MH batteries

I would like to power my RPi2 from the 5V GPIO pin via 4 Ni-MH rechargeable batteries (4.8V) but I'm afraid about peak current. Can it somehow produce more than 2.5A? Should I use a fuse to limit that ...
2
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1answer
64 views

PI 2 - GPIO pin stays HIGH even when I toggle ( in Java)

Hi my first Java program to control a LED has failed, the LED does not come on even though the pin state is continuously HIGH ? Heres the Java code :- final GpioController gpio = ...
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1answer
35 views

GPIO's firing every ~3 milliseconds

I'm currently building a project using adafruits arcade buttons, and seem to be having a bit of an electrical problem. Using a Raspberry Pi 2 , and after confirming that wires aren't touching in ...
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1answer
33 views

Trying to shortcircuit a computer motherboard pin with the Raspberry Pi

So I'm working on a project which requires me to compile the kernel of my desktop machine at the office. But I do a lot of work at home using SSH. As the kernel is very delicate, it causes a lot of ...
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50 views

Connecting multiple devices with UART

So, I have the following components: Gertbot SparqEE Shield My aim is to connect these to a Raspberry Pi Model B+, so that they can work together. There are no issues when I connect these ...