Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. 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
-2
votes
2answers
6k views

UART interrupt in Raspberry PI with c or c++

I want use GSM module with raspberry pi i can send data bur for receiving data i want to use a interrupt function.pulling is valuable for me.
12
votes
2answers
923 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 ...
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 >>...
4
votes
2answers
30k views

GPIO: Warning Channel already in use

gpio.py:5: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings. GPIO.setup(8, GPIO.OUT) That is what I get after I run: import RPi....
3
votes
1answer
7k views

I short circuited 5v & gnd of Rpi

Accidentally I short circuited 5v & gnd of R-pi, since then my R-pi is not working. How can I make it start again by means of replacing some IC or power regulator or anything ? Please help.... ...
3
votes
1answer
591 views

How long to wait after shutdown to cut power

I am working a problem that seems to be fairly popular with the Raspberry Pi community. In essence, I am designing a circuit that will utilize a DS3231, a 555 timer, and a load switch to cut power ...
0
votes
2answers
285 views

Which GPIO pins on previous modela are equivalent to those on the B+ model?

The problem I am having is that the B+ model has more GPIO pins than previous models. I'm not sure of the exact number, I've not counted and I don't think it matters for my questions. You can see ...
0
votes
1answer
4k views

Controlling a brushed motor ESC from the Raspberry Pi

I've tried solutions from similar problems, but none of them gave me any usable results. I'm trying to control those http://www.ebay.com/itm/311177661450 electronic speed controls (ESCs) with ...
0
votes
2answers
264 views

How to know if Raspberry is running

I'd like to implement an electronic circuit to be able to restart my raspberry Pi when it has been shutdown (without plugging in and out the USB charger, which will obviously remain plugged all the ...
0
votes
1answer
8k views

The Pi Zero W has 5v and 3v rails. What is the max current per GPIO pin on the 5V rail?

What is the max current per GPIO pin on the 5V rail of the Pi Zero W? Also, can I power a 5V relay (4 channel, each requiring 15-20 mA) from this rail? If not, does anyone know of a 4 channel relay ...
0
votes
1answer
603 views

Long length of wire off of GPIO pins

I am building a circuit with the Raspberry Pi that requires a button about fifty feet away from the central circuit. I am planning on using speaker wire for the connection from the Pi to the button. ...
13
votes
5answers
15k views

Can I use a DHT22 as a temperature sensor for my Pi?

Is it possible to use a cheap temperature sensor such as the DHT-22 with the Raspberry Pi? I have found Arduino drivers for this and many similar things, and would be comfortable porting the code to ...
8
votes
2answers
14k views

Driving PWM output frequency

After many hours of fruitless searching and reading, I still didn't have a complete understanding of how and why to output specific frequencies from the hardware PWM pin on the RPi without using ...
8
votes
1answer
6k views

Reading GPIO states using C

I've implemented this example to familiarize myself with basic GPIO programming in C. The code demonstrates how to write to GPIO pins but does not explicitly state how to read the state of pins. I ...
6
votes
4answers
23k views

RPi GPIO as a high-speed square wave generator

I'm trying to make RPi generate high-speed square wave through its GPIO pin. My code controlling GPIO output is based on this article The essential part of my code is the following: speed = 1000000;...
13
votes
4answers
26k views

Raspberry PI and fingerprint scanner

How can I make Raspberry PI work with a fingerprint scanner like this? I found something for Arduino only (http://learn.adafruit.com/adafruit-optical-fingerprint-sensor) Are there any tutorials for ...
13
votes
3answers
10k views

Maximum current on each GPIO pin for Raspberry Pi 3 Model B

Anyone knows what's the maximum input/output current for the individual GPIO pins? Perfectly fine if someone is able to point me to the Broadcom BCM2837 datasheet, which I for some reason, cannot ...
4
votes
3answers
18k views

Plug a 5 V fan to GPIO 1 and 2

Regarding to the following picture, I understand that I can plug a 5 V fan by plugging it in between pins 1 and 2. Is this right (+ on 1 and - on 2?)? My need: Plug a 5 V fan to run all the time the ...
13
votes
1answer
3k views

Zero-crossing activated relay

How could I go about programming a switch (based on solid-state relay or a triac) that triggers on zero-crossing power? For these not familiar with the subject: Switch 230V power on, when the sine ...
7
votes
3answers
3k views

What is the nominal GPIO Pin Output current?

What is the RPi GPIO Pin output current? I assume it's more than 10mA since it can drive LEDs without any problem but what is the spec?
4
votes
2answers
2k views

What is the best way to increase digital I/O lines on Pi?

In one of my projects I need six PWM outputs, 12 digital I/O and around six analog inputs to be controlled by a Raspberry Pi. What are some of the best options available to increase the I/O capability ...
2
votes
3answers
10k views

Is it possible to connect an LED directly to the GPIO of the Pi?

I was wondering if it is possible to connect an LED directly to one of the GPIO pins of the Pi? The reason I ask is that, I have read from many sources that if I am not using some sort of break out ...
11
votes
1answer
14k views

Does short-circuiting GPIO pins damage the Raspberry?

Does accidently connecting the wrong GPIO pins damage the Raspberry Pi or is there some protection like a fuse?
9
votes
3answers
3k views

GPIO pin voltage is too low to energize relay

I am trying to toggle a small relay on and off. I have connected a GPIO pin and GND directly to the relay. I can hear the relay clicking, when I set the GPIO pin to HIGH. However, the relay only ...
7
votes
2answers
17k views

Automatically run a program as root for GPIO?

I have a Raspberry Pi running Raspbian that I want to auto-login and then automatically run a program that uses the GPIO as root. I have auto-login working as per this website. What is the best way ...
5
votes
1answer
587 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....
4
votes
1answer
2k views

gpio /value file appears with wrong permissions momentarily [closed]

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 ...
3
votes
1answer
5k views

8x8 matrix of buttons

It is possible to connect 8x8 matrix of buttons to the Pi using 16 GPIO pins, 8 for rows and 8 for columns? What are possible alternatives of doing this?
3
votes
4answers
5k views

How to control a Traxxas XL-5 ESC directly from the GPIO?

I am trying to control the ESC (Electronic Speed Control) of my Traxxas RC car with my raspberry pi (rev.2). I have been looking through the internet and while I can find some projects that seem to ...
18
votes
1answer
12k views

Do all GPIO pins have a internal pull-up/pull-down resistors?

So question is: Does all Raspberrys GPIO have a internal pull-up/pull-down resistor which can be enabled from program, in my case Java language with PiJ4? I have Raspberry Model B+.
10
votes
2answers
14k views

RPi as a Sound Level Meter?

For my daughter's science fair project (Computer Science and Math category), she'd like to use the RPi to go around and measure whether different loud sounds are above the threshold of pain and are ...
8
votes
3answers
8k views

How to detect whether there is voltage between two points via GPIO?

I'd like to detect whether an external device is switched on or off. I found two pins where there should be 5V between in the first case, but the voltage may vary a bit and I don't wont to break the ...
5
votes
4answers
31k 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
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 ...
4
votes
2answers
7k views

How fast can GPIO pins toggle?

I'm currently using Python's RPi.GPIO module to toggle some pins, and I want to know how quickly it can do this. I need the pins to be toggled on the schedule of a ~50 mhz FPGA clock, which I'm ...
3
votes
1answer
806 views

Is there a way to make a RP3-B act as a USB gadget/periferal?

I have a Raspberry Pi 3 (Model B) that I would like to act as a USB gadget or OTG peripheral. Some sources state (without proof) that the USB_ID line is not connected properly, to allow any software ...
2
votes
1answer
266 views

Lirc - interference from power line

IR remote stops working after switching lights (or other electrical equipment) in the same room. The service of the lirc returns to normal after some time without doing anything. There are ...
2
votes
2answers
2k views

GPIO input connected to garage door button

I would like to connect the garage door's button to a GPIO input on my Pi. I want to be able to trigger actions when someone pushes the button. I am able to read the status of a basic switch using ...
2
votes
1answer
506 views

Raspberry Pi 3b+ do not detect DS18b20 on 1Wire

Problem: The new raspbian kernel does not detect the DS18b20 sensor over the 1wire bus. This is due to the Device Tree that was added to Kernel 3.18.8 What hardware used: Raspberry Pi 3b+ Kernel: 4....
2
votes
1answer
1k views

How to get MCP23s08(8 bit I/O expander) working with GPIO on Raspberry Pi?

I have an MCSP23s08( 8-bit SPI I/O expander) and a Raspberrypi. Does anyone know what I need to plug where to get them to communicate?I want to read data from MCP23s08 and write it to GPIO pins of ...
1
vote
1answer
2k 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 ...
1
vote
1answer
6k views

How to get pin addresses on a MCP23017

Recently I purchased a few MCP23017. I've been reading up on them and I've gotten a few lights to turn on and such. I am having a problem trying to understand how to figure out the register address ...
1
vote
2answers
610 views

Relay status led's are blinking but the relay coil is not activating

Devices I am using are: 1) Songle 2 channel relay module - https://www.electronicscomp.com/2-channel-5v-relay-module-with-optocoupler?gclid=...
7
votes
2answers
4k views

Permissions on /dev entries

I'm waiting for my Pi. From reading the tutorials and books on doing i/o on the Pi I'm getting the impression that linux makes entries in /dev on the fly, which is nice, but they're owned by someone ...
4
votes
3answers
2k views

rPi2 model B v1.1 smoke comes out near power port

I am trying to control 2 motors using the E-gizmo Motor driver shield but suddenly smoke comes out near the power port of the raspberry pi 2 so I immediately unplugged the power supply. After that, I ...
3
votes
1answer
6k views

Differences in GPIO between Raspberry Pi 2 B and 3 B

Is there any difference in the GPIO layout between Raspberry Pi 2 B and 3 B? If yes, please provide the differences.
3
votes
1answer
2k views

How to use a GPIO pin after I put on a HAT?

I got a Speaker pHAT for my Pi Zero. According to the pinout, it only uses 5 GPIO pins, so plenty of room to add something else. The problem is, I'm not sure what's the best way to physically attach ...
3
votes
1answer
2k views

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 ...
3
votes
2answers
2k views

Raspberry pi GPIO extension

I recently started using rasperry pi. I am trying to do some home automation and controlling toy car motors. I am able to control the motors and 2 plug points. I wanted to control more servo motors. ...
3
votes
1answer
283 views

TMP36GZ/DS1822 Temperature Sensors not outputting any values

I am trying to connect a temperature sensor to my Raspberry Pi using this tutorial for Windows IoT Core. I have connected all of the wires and MCP3002 correctly, but I cannot read in any values from ...