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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Determining correct J3 jumper setting on Compute Module IO Board

The Raspberry Pi Compute Module Development Kit Quick Start Guide says that prior to using the kit, the IO bank voltage jumpers (which power the GPIO banks) should be checked. However, I can find no ...
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How to make a remote pigpiod socket call?

The pigpio GPIO library seems to provide a mechanism to invoke the pigpiod demon remotely using TCP/IP sockets. However, there appears to be some details missing. For example: Do we use a TCP or ...
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21 views

The Current in mA at 3.3 V When Using the Internal Pull-up Resistors

I'm using RPi.GPIO in Python 3. If I do GPIO.setup(24, GPIO.OUT, pull_up_down=GPIO.PUD_DOWN) GPIO.output(24, 1) will then a current flow internally from the pin to ground even if it is not ...
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Understanding the library from MCP3002 ADC chip

can somebody explain to me about this mcp3002 library used in analog to digital conversion?? It has some connection to my first question here. # botbook_mcp3002.py - read analog values from mcp3002 # ...
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32 views

Gpio state can't be changed when connected to a DC motor or led

I am using the pi4j library to control the gpios on the raspberry pi B, but I ran in the following problem: when I start a pi4j example like ControlGpioExample.java then the led(with resistor 220 ohm) ...
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Can we determine the mode of a GPIO pin?

As I understand it, the mode of a GPIO pin can be INPUT or OUTPUT (and I think there may be other modes such as PWM and I2C). I believe that the mode of a pin is a global and that if two applications ...
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52 views

How to Connect 9 Volt RS232 to Raspberry Pi GPIO

I am trying to connect RS232 Port to Raspberry Pi using PL2303 USB To RS232 Converter and PL2303 USB To RS232 TTL Converter These Both connect at /dev/ttyUSB0 I try minicom command to read ...
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Install Java MP3 library [migrated]

I am working on a sound board for the raspberry pi with Java. I used the libary Pi4j to make it possible to read Gpio pins. To play a Mp3 we modified the code of an Pi4j example ...
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43 views

how to connect RS485 Port to Raspberry Pi?

I have a battery controller which give Voltage of battery via RS485 Half Duplex Transmission using RJ45 port. we can connect this device to windows pc using these cable/convertors. When we ...
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20 views

gpio export works, but gpio write wont

It seems that I am missing something or I have mis-configured something. I have a garage door opener connected to a relay to my GPIO. If I use gpio export 17 out the circuit will complete and the ...
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19 views

Troubleshooting MCP23017 based display

I am having trouble getting characters to display on my Adafruit 16x2 blue/white monochrome LCD + keypad. I am wondering how best to isolate the problem as either hardware or software. It shows up in ...
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82 views

Problems Regarding Raspberry Pi Project with MQ-2 Gas Sensor

Recently I have been learning Python implementations on Raspberry Pi's GPIO system. I'm interested in wireless sensor network examples and decided to make a fire alarm system using MQ-2 sensor as the ...
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36 views

How to have a Raspi trigger a Remote Control physically

I have a Remote Control for my windows shades and I would like to be able to trigger them using some software using a web interface or an android app. As I am an enthusiast programmer I would like to ...
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35 views

ruby on rails in RPI

I want to control my RPI from my phone, so I decided that the RPI will host a site. I'm familiar with ROR and I saw that there is GPIO gem (pi piper). Should I work with ROR or learn Django and use ...
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35 views

Soil hygrometer without adc

I want to measure soil moisture using THIS sensor. I do not want to use ADC. In the sensor there is a digital output port and an analogue output port. I can use the digital output of the sensor ...
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20 views

GPIO Input fluctuating between high and low when no input is received

I've got a fairly simple circuit that I've made where a motion detector is connected to a Raspberry Pi B+ GPIO by way of a fairly long ~30ft stretch of wire. The detector is being powered by a 9V ...
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27 views

how pifm pwm modulation works?

thanks in advance , i want to know how the pwm modulation of pifm works more precisely why the size of the buffer of data to be read in each iteration is 1024 bytes and how this buffer pcm data could ...
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38 views

Problems triggering via GPIO

I am building a network of Raspberry Pis, and want a lot of Raspberrys to take a picture after receiving a Trigger Signal. I want to send this Trigger Signal via a GPIO Pin. It sounds simple, and I ...
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30 views

dt11 is not detected on raspberry pi 2

I am trying to setup dt11 sensor using T-cobbler but its not getting detected. For reference attaching the screen shots. Any help really appreciated :) Thanks, sushanth
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Raspberry Pi Project: Binary Pascaline

I'm working on a school project and want to create a Pascaline, but use binary instead of base ten for the cogs. Hoping to just run by my steps by some of you more experienced souls and see if I'm ...
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59 views

Python taking pictures with raspberry pi camera

I have written this code to take a picture when it detects motion however when I run the code it prints 'picture taken' but does not save the picture. I know my camera works as I tested it in LX ...
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39 views

Can Mike McCauley bcm2835 C library access all 26/28 GPIO pins on Raspberry Pi 2 Mod B?

Can Mike McCauley bcm2835 C library access all 26/28 GPIO pins on Raspberry Pi 2 Mod B?
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43 views

Change GPIO pin mode to ALT with Python RPi.GPIO

I usually use RPi.GPIO module like this to set up the GPIO pins: import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP) GPIO.setup(17, GPIO.IN, ...
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65 views

Set some GPIO pins OFF during boot, and ON later

I'm using +3.3V / GND / TX pins to power this 7-segment display with Serial Port connection. It works, but during booting time, the display displays random things, probably because it receives ...
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74 views

Need help finding problem with webiopi GPIO header

I'm a total noob when it comes to programming. This is my first time experiencing a raspberry pi and my first project is to be able to control my garage door from anywhere with an internet connection ...
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42 views

Wiring TFT Display to Raspberry Pi 2

I just need some help wiring this TFT LCD for the Raspberry Pi. I want to use it as a console/x display. I've Googled and read through everything I could find on SE, but I can't apply what I find to ...
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44 views

GPIO not working after installing the webiopi

I was doing programs with LED's and the GPIO after I installed the Webiopi to access it from the internet it didnt work anymore, I tried installing the latest version of Python and the rpg.gpio and ...
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18 views

can I program gpio led light to flash on particular website?

I have used python to create a program that lights up the led through GPIO on the rasberry pi. I was wondering if and how I could write a python code so that the led light would light up only when I ...
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22 views

Detect stall current from motor and send gpio signal

I have a project which has a 12 V DC motor controlled by a raspberry pi through a l293d. The motor draws about 600-800mA from the power source while it is running, and > 1A (much greater) when it ...
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65 views

How to shutdown GPIO elegantly when using kill to stop Python script running in the background?

I'm using GPIO in a Python script, and I've wrapped my code in a try... except block so that GPIO is exited elegantly if I need to abort the script: GPIO.setup(17, GPIO.OUT) # Configure GPIO so that ...
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47 views

GPIO input using a banana?

I am programming a music player that will be controlled by a bunch of bananas for the main functions as play/pause/etc. How do I get a GPIO input of banana (in a way that it registers an input when I ...
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35 views

using gpio for positive and neg outputs

I am an electrician and have little programming ability at the moment but am trying to learn. I was wanting to know how many gpio pins can I switch and are the only certain ones that will be positive ...
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38 views

Problem when trying to get a DC motor to run using the L298N H-Bridge?

My setup is as follows: Using this motor controller board, I have one DC motor (I'm new to electronics, so I'm not sure when I say it's rated at 1.5V, because one 1.5V AA battery on its own makes it ...
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19 views

Using old alarm keypads as displays

I have a few old IDS alarm keypads lying around(both 8 and 16 zone) and was wondering if I could somehow hook them up to my pi.(LED only, no LCD) Power can be supplied via the alarm panel, so I just ...
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123 views

How do I read a car turn indicator is on using GPIO

I am brand new to the Raspberry Pi (PM now born-again developer, Pi still in the box etc) and this is my very first ever post so please don't slam me if I use the wrong protocol to ask this question. ...
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55 views

Uart TxD & RxD voltage

What's voltage of RPi pins 14 & 15 (RxD & TxD)? I want to use an octocouplers, so I'm very interested in voltage parameter.
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ADAFRUIT 16 Channel hat stacker

I recently bought want to equip the adafruit 16 channel hat to the RPi. But I want to maintain the use of the GPIO's. I have some motors which work from the GPIO (i know they can be programmed on ...
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75 views

Do I need a current limiting resistor in series with a magnetic door sensor?

I'm building an alarm system and I'm using a magnetic door sensor, conected to ground and a pin of the gpio set up with an internal pull-up resistor. As far as I know, this means that the pin will be ...
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22 views

Unwanted multiple presses when using GPIO button press detection

I use this to detect momentary button (connected to GPIO) press : import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP) def my_callback(channel): ...
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94 views

I2C not working as expected

I'm running a Pi B+ rev 1.2 and recently acquired 2 I2C modules: DS-RGBW.S LED lighting Microstack accelerometer: When connecting the LED module, address 70 appears to be occupied as planned. I ...
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158 views

How to connect 7-segment 4-digits display with Pi?

I would like to connect such a 7-segment 4-digits display (with common anode) to the Raspberry Pi: What's the simplest way to do it with Python for example? Do I need the RPi.GPIO package? Is there ...
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39 views

GPIO pins turning on unpredictably

I have four GPIO pins and a GND pin wired into the circuit board of a monster truck, and a couple pins seem to be going and staying high without any prompting. I've been using RPi.GPIO, and I've ...
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84 views

Is there a difference from one GND pin to another?

There are 4 ground pins on the GPIO are they all the same? Are the extra pins just there for convenience? I have an expansion breadboard does it matter which gnd slot I plug into? thanks
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95 views

How to wire up a DHT11 temperature sensor

I'm a Raspberry Pi (and hardware) noob and am trying to hook up a DHT11 temperature and humidity sensor. I've found two separate guides, and I'm seeking advice as to which I should follow. This UU ...
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40 views

New Raspberry Pi SPI Interface Question

I was looking at the new Raspberry Pi. I wanted to know if the SPI Interface will be able to sample at a higher sampling rate. Does anyone have any information on this? According to this page, the ...
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53 views

Raspberry Pi Frequency Calculator

I'm trying to make a simple program that calculates the frequency at a pin on the board. I'm using Python for the programming. I wrote two different programs and they gave the same (wrong!) results. I ...
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54 views

Neato Lidar to Raspberry Pi? [closed]

How would one connect the neato lidar to the raspberry pi? I know that there are a lot of choices, such as GPIO or USB (with this?), but which one is the best with the least latency? I would love for ...
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Multiple servo control RPi

I have written the following script to set positions for a single servo. import RPi.GPIO as GPIO import time #set up pin 11 as an output GPIO.setmode (GPIO.BOARD) GPIO.setup (11, GPIO.OUT) ...
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76 views

Why doesn't GPIO commands work?

I have upgraded to the new rPi B+ 2 now from the old B model. Keep in mind that everything worked fine with my older boards. Now with my newer boards it does not. I have my script in the rc.local ...
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633 views

Should GPIO pins 13 and 14 be soldered together?

I just bought a new Model A+ board, and noticed that the GPIO pins 13 and 14 (board pins 21 and 23) are soldered together on the backside. This was not the case with my previous A+ board: see the two ...