Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

Questions tagged [gpio]

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.

Filter by
Sorted by
Tagged with
6
votes
2answers
8k views

GPIO pins are always HIGH

I recently have started delving into using the GPIO on my raspberry pi and when I got to the input section of adafruit's tutorials I noticed something wrong. For some reason when I execute the python ...
6
votes
2answers
2k views

Impossible to scan RFID tags using libnfc, PN532, and RPi3

I recently bought this NFC/RFID reader PN532 module V3 I want to use it with my raspberry pi 3. I have install and configured the library libnfc. The PN532 is connected with I2C. I have well enabled ...
5
votes
5answers
6k views

Is there a component out there that can push a button i.e. will extend a rod about 1 inch and then retract it?

I'm basically trying to find something that can push a button for me. I want to be able to control it through code, just like you can with motors, LEDs etc.. via the GPIO on a Pi. I want it to extend ...
5
votes
4answers
2k views

What is the maximum number of RGB LEDs that can be controlled individually?

I've read that 17 LEDs can be controlled individually with the 17 GPIO pins. Does that mean that only 5 (17 / 3 = 5.6) RGB LEDs can be controlled with one Pi? Would it be possible to individually ...
5
votes
2answers
10k views

How many volts can you safely connect to the Pi?

I want to purchase this power supply (battery pack) for mobile projects (I know, it isn't a lot of power), and I was wondering if, with a bit of modding, like adding a micro usb tip to the power or by ...
5
votes
3answers
8k views

How to Run pigpiod on boot

In order to use pigpio Module in Python (remote GPIO for Raspberry Pi ), pigpiod has to be loaded to memory on each RPi. what is the right way to to it ? during Ubuntu's boot or a part of Python's ...
5
votes
4answers
4k views

How do I control GPIO-connected fan via code at a certain CPU temperature?

I have just bought a 5v Pi fan for my Pi3. I'm using Retropie 4.1 for the OS. I have connected the red and black wires of the fan to ground and GPIO 18 respectively. How can I get the fan to start ...
5
votes
4answers
907 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 ...
5
votes
4answers
30k views

How does python GPIO bouncetime parameter work?

I have a simple Python script that is observing two GPIO pins, I've set the bouncetime parameter to 500ms, but I get multiple (almost always 2) calls to my callback, usually 3 or 4 ms apart. This is ...
5
votes
4answers
17k views

Show IO value on webpage in realtime

I would need to check the value of a IO pin in realtime over the LAN. Since I need to do it from differnet devices (pc, palm, iphone, Samsung galaxy etc) I was thinking of a webpage. The value can be ...
5
votes
4answers
2k views

“Blinking” relay by toggling pins between input and output

Edit for searches: This question is about using a 5v relay with Raspberry Pi GPIO pins that outputs 3.3v. There are a number of great questions below, read them through to understand whats going on. ...
5
votes
3answers
8k views

Is the GPIO configuration changed for Raspberry Pi Zero

When I wanted to start working with Raspberry Pi Zero, I presumed the GPIO configuration is the same as for A+, B+ and Pi2 and I wanted to confirm it is true. However, I couldn't find an official ...
5
votes
1answer
3k views

conflicting dtoverlays

I'm using a GPIO connected display 1 which requires a patched kernel and dtoverlay=4dpi-3x in /boot/config.txt I would like to use a DS18B20 temperature sensor which requires dtoverlay=w1-gpio to show ...
5
votes
3answers
6k views

Do the GPIO registers have the same addresses on the new Raspberry Pi 2?

So I just found out that the Raspberry Pi 2 came out, and I'm wondering whether stuff like this would work on it without any modifications (except for recompiling it for ARMv7 of course). This piece ...
5
votes
4answers
2k views

Raspberry pi control GPIO with Haskell

I'm working on an home automation system with the raspberry pi. Currently I use python or C to control the GPIO and haskell/yesod for controlling everything from pc/ipad/phone... But I would like to ...
5
votes
2answers
2k views

UART Output working on 57600 Baud but with 115200 only gibberish

I've got a strange problem with serial output. Using Wheezy and 8 Databits, 1 Stopbit, NoFlowcontroll, NoParity (config as stated in eLinux Wiki). With 57600 Baud everything works fine but with 115200 ...
5
votes
3answers
6k views

Connect sim800 to Raspberry PI (RX, TX)

I've been trying to connect my sim800L to my Raspberry pi 3 model B (rasbian) but without success... I'm at the very first step, and since I'm new to Raspberry pi, I don't understand very well how it ...
5
votes
3answers
4k views

Connecting blue LED (3.3V)

I've recently started doing basic diode connections (red and green diodes). I've also got blue diodes, but there's one thing that prevented me from connecting them already, namely - the specs say they'...
5
votes
1answer
14k views

SPI example with Raspberry Pi and another MCU

I've never used SPI before (for serial communication) and was wondering if any experienced Pi users out there know if the Pi board can use SPI to send and receive data to other MCUs on different ...
5
votes
3answers
6k 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 ...
5
votes
2answers
2k views

Raspberry Pi to Arduino (Leonardo) avoiding latency

I'm using a Python script via (TkInter) on the Raspberry Pi to capture mouse movement and events. My goal is to send this data, in real time, to another connected Arduino device(Leonardo). My first ...
5
votes
2answers
2k views

What are the capabilities of the GPIO pins?

The Raspberry Pi has 26 GPIO pins. What are the names, functions, and important limitations of each?
5
votes
2answers
1k views

Button & 2700 Ohm Resistor?

i have a flip switch and a 2700 ohm resistor and i want to read the state with python. The code-part isn't a problem to me but is it possible to use this components to wire it up to the GPIOs to read ...
5
votes
1answer
69 views

Is there a GPIO current limit function available, and where is the documentation?

I have read that limits may be programmed for the output current of GPIO pins. However, after reading several online versions of Broadcom's data sheet for the SoC, I've found nothing to corroborate ...
5
votes
1answer
629 views

RJ11 connection, for easily plugging and unplugging temperature sensors

So I have bought 8 temperature sensors (DS18B20), and successfully used them with my Raspberry Pi. These sensors each have three pins, one for voltage, another for data and the last for ground. For ...
5
votes
3answers
2k views

Can't turn on ACT LED on baremetal Pi3

I'm trying to run some bare-metal code on my raspi 3. This is my first time doing any sort of bare-metal programming, so first things first I want to turn on my ACT led as a kind of hello-world type ...
5
votes
2answers
8k views

Polling GPIO pin from C, always getting immediate response

I'm using C to read the GPIO pins from /sys/class/gpio. I have a separate thread that I'd like to get notified when a pin changes value, so I'm opening the file for read, then calling poll() on it, ...
5
votes
1answer
3k views

Can you connect multiple GPIO pins, to one ground pin?

I'm questioning whether connecting multiple GPIO pins (which to my knowledge are 3 volts), to one ground pin, is going to damage my Raspberry? I want to connect GPIO pins to breadboard, pass the ...
5
votes
2answers
492 views

How to indicate read / write disk operiation via LEDs connected to GPIO

I think I know how to connect LEDs to GPIO but I want to illuminate them when there is read / write operation to sdcard or other mass storage connected to Pi/ Is it possible ? I am doing little ...
5
votes
1answer
621 views

I need to control 8 LED's but I can only control 3? [helpful pictures attached]

I'm very new to electronics in general, but I want to build a small project where I can individually control (from a GPIO pin) 8 LED's. From what I understand, each GPIO pin on the Pi (Pi2 model B V1....
5
votes
1answer
4k 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 ...
5
votes
2answers
4k views

Is the 26-pin Pi cobbler compatible with the 40-pin Raspberry Pi?

I'm a Raspberry Pi noob, and accidentally purchased a 26-pin Pi Cobbler - then realised I have the newer 40-pin Raspberry Pi Model B. The 26-pin cobbler won't physically fit on the GPIO board due to ...
5
votes
1answer
6k 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 ...
5
votes
3answers
8k views

How to use 2 x MCP23017?

I need to control 32 L.E.D's individually, now looking through the forum, the common solution is to use MCP23017 chips, as they can control 16 l.e.d's. With that in mind, I would require two chips. ...
5
votes
1answer
3k views

Using BCM GPIO pin numbers with wiringPi C library

I'm a GPIO newbie experimenting with getting my Raspberry Pi to blink an LED with C using the wiringPi library. The example code at http://wiringpi.com/examples/blink/ (blink.c) compiles perfectly and ...
5
votes
1answer
4k 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 to ...
5
votes
1answer
12k views

How to add isolation between raspberry pi and relay board?

I want to use my Raspberry Pi to control mains(fans,lamp on 240v). Its very difficult to procure a good and reliable relay board for me in India. After bit of searching, I have decided to go with ...
5
votes
1answer
1k views

Physical switch that can be toggled by Raspberry PI

I've a raspberryy pi setup which can control a light bulb using the GPIO pins and a SSR. The problem is that I'd also like to use the physical switch to control the light bulb (so people don't freak ...
5
votes
2answers
3k views

Can I directly control a floppy drive from the Raspberry Pi's GPIO?

Is it possible to connect the GPIO's pins to a floppy drive? Not about the shape of the IDE cable, but about a voltage problem, may I ruin something?
5
votes
2answers
967 views

When to power GPIO projects from external power source?

I am working on a home automation project using: rPi 3 with 2.5 A power source 3 x MCP23017 for GPIO port expansion 3 x 8 ch solid state relay board by Sainsmart 20 x physical wall switch (future) ...
5
votes
2answers
541 views

Board sign from LED strips

I'm trying to build a sign board made of LED strips, just like this I found a ton of examples on controlling a single strip and also examples using the adafruit premade led boards (16x32), but no ...
5
votes
2answers
3k views

Pi with C# instead of Python

I am very new to Pi but have a RPi 3 running windows 10 I.O.T. core. Can I do c# on it instead of Python? I am interested in some I.O.T. project using Pi but they use C instead of python which is more ...
5
votes
1answer
840 views

How to Check GPIO pins simultaneously?

Can you give me an idea on how to check the statuses of specific GPIO pins if it is HIGH or LOW? My project is all about checking the statuses of GPIO pins (6 GPIO pins). I want to check all of the ...
5
votes
2answers
707 views

Voltage conversion & input circuit for Raspberry Pi

I want to convert a 24V signal from sensors to 3.3V input signal for a Raspberry Pi. I have almost 20 sensors, so I have to convert all to 3.3V. Is there any IC from which I can do multiple voltage ...
5
votes
2answers
8k 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 ...
5
votes
1answer
583 views

GPIO Temperature Sensor not Recognized

I recently tried to connect a temperature sensor (http://www.adafruit.com/product/381) to my RasPi via the GPIO, with a 4.7k (2Watt) resistor connecting the power and data (Source: http://www.cl.cam....
5
votes
1answer
5k views

Is my Pi's GPIO damaged?

I am trying to test GPIO output on a Raspberry Pi, and I am wondering if it is broken. These setups work: 3v3 >> +LED terminal -LED terminal >> resistor >> GND (the LED is unusually dim here) 3v3 >>...
5
votes
1answer
17k views

Live video streaming embedded in a web page [closed]

I have created a web page to have both live video streaming and some button controls to control the robotic arm interfaced to the RPi GPIO pins. For button controls, I used php coding. The php coding ...
5
votes
3answers
6k views

Can I transform GPIO pins into a CAN bus

I need a CAN bus and the Raspberry Pi doesn't have this. So, I would like to know if it is possible to transform some GPIO pins into a CAN bus. Which libraries would permit this? I would like to ...
5
votes
1answer
6k views

Max current from 3.3v power pins (for RPi model B+) - Higher Than You Were Told!

There are many references to a maximum limit of 50mA when sourcing power from the two 3.3V power pins on the GPIO (just for clarity, I am NOT referring to the I/O pins). However, I suspect this ...