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.

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709 views

How fast can GPIO pins toggle on the Pi 4?

Benchmarking of the Pi 4 using the Python GPIO Zero library shows a significant increase in the frequency of toggling a GPIO pin on and off compared to previous models. This result is attributed to ...
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157 views

Raspberry as I2C Slave, how to slow down transfer rate?

I have had minor success using the PIGPIO library and interfacing the Pi as an I2C Slave (Using GPIO Pins 18 and 19 as SDA and SCL) with a Campbell CR1000X Datalogger I am encountering a problem ...
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827 views

Can I control GPIO Pins when using Android on the Pi 3?

I want to install Android on my Raspberry Pi for implementing a GUI app, which is easy to create using Android Studio. But now I am confused about how to control the GPIO pins on the Pi 3 to turn on ...
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2answers
349 views

Pi4J kills USB bus?

Hello fellow Pi enthusiasts :) I am currently attempting to control a standard 16x2 character LCD display from the PI's GPIO pins from Java. I downloaded Pi4J and wrote a small program to initialize ...
3
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0answers
56 views

DCF77 time signal emulator by Raspberry Pi Zero WH

This is my first post on this forum. Thanks for being welcomed into this community. I am struggling with my second project with a RaspberryPi. On Github I found a very interesting project of an ...
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41 views

Is it possible to control servos in both directions on the RPi?

I have been working on controlling servos in one direction with PWM control via GPIO ports on my RPi 3. I've worked with motor controllers that use PWM before and it seems that I should be able to ...
3
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0answers
92 views

Raspberry Pi button bug, what is happening?

I am new user of raspberry pi. I have two buttons, and some code to run, yet the led will not react to the buttons. It's probably a easy fix, but keep in mind, I am new to robotic and have only ...
3
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1answer
160 views

How to use Rpi GPIO to PWM adjust IR LEDs brightness?

I'm using this circuit for my project, which I referred from https://www.sparkfun.com/news/1396. I don't really understand how current works in GPIO pins, so the question is: instead of connecting ...
3
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1answer
272 views

Controlling a High Power 13V DC Motor with in-built Hall Effect sensor

I am a beginner with electronics and RPi. I have a Brushed DC Motor that runs at a constant 13V and draws about 4-5 A while running and about 18-20 A at stall. It also has a single Hall effect sensor ...
3
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143 views

Is it possible to virtually trigger a GPIO Input pin when nothing is actually connected to it?

I am trying to use incoming MIDI data on my Raspberry Pi 3's USB port to virtually trigger an input GPIO pin. The reason for this is as follows: I'm using the MIDI out port on a Behringer X-32 audio ...
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867 views

How to properly trigger multiple Raspberry Pi camera modules via GPIO?

I am working with three Raspberry Pi 3 B boards, which in turns have RPi camera modules V2 connected to each. I followed this very detailed post about triggering another Pi using GPIO pins and it ...
3
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1answer
958 views

Not getting a response from a connected PIR sensor

I have a PIR sensor which I'm using connected to a Raspberry Pi 3 Model B as part of a Magic Mirror project. I'm running this module for the sensor. I've had the Motion Sensor working before, but now ...
3
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1k views

Which GPIO pins are used for I2S audio I/O

I am trying to set up the ADAU1781 as an audio codec for the Pi 3 B, communicating with the Pi via the GPIO pins. Which pins would I use for I2S audio input and output? I have been doing a lot of ...
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5answers
2k views

GPIO to hifi amplifier's trigger input (remote power on). Protection? Circuit?

I use my raspberry 1 B+ with a DAC board (like hifiberry) and volumio/moode audio distribution. The board is working as a pre-amp and it's connected to my hifi amplifier RCAs input, sending analog ...
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0answers
558 views

DS18B20 temperature sensor not found in folder

I've bought the camjam edukit 2 for my pi which includes the DS18B20 temperature sensor. However, after going over the instructions 20 times, rebuilding it a same amount and searching online, I still ...
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0answers
3k views

GPIO23 (BCM) is busy when using /sys/class/gpio but I am able to use wiringPi pin 4 (GPIO23)

I'm having a bit of trouble accessing GPIO23 using /sys/class/gpio/. To clarify a few terms (according to the table on this page): Header pin 16 is BCM GPIO 23, which is wiringPi pin 4. Header pin 11 ...
2
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3answers
35 views

connect multiple temperature sensors to rpi

I need to connect multiple temperature sensors to my RPI. can you, please, elaborate whether/how can this be done with this or this unit? or can you suggest other unit? I need to measure temp on the ...
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0answers
24 views

Button hardware for RPI

I have the following circuit: I am wondering if this configuration will work if I'm trying to add buttons. I wanted to set them up as GPIO=GPIO.PUD_DOWN and to have it activate on the rising edge, ...
2
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0answers
40 views

Using GPIO on the Bitwizard DMX hat board

I have a rpi 4, with a relays board on top of it, and a Bitwizard DMX hat board on top of that. The Bitwzard board doesn't have a male header on the top, so I am unable to connect my sensors. It was ...
2
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0answers
29 views

More than 2 SPI slaves

I like to connect more than two SPI slaves to the Raspberry. Just want help how to configure my Raspberry Pi Zero.
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0answers
110 views

How to use Rpi UART to debrick a bricked LinkSys G (WRT54GL) Router?

I was working on a project that 'debricks' my bricked router(WRT54GL). Since this is my first time with Serial communication on any device, I have some questions to ask. This is the pinouts for the ...
2
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0answers
98 views

LIRC mode2 shows no output

I am trying to receive configure an IR remote control for my raspberry and I configured LIRC on the Pi and it works all fine but I won't be able to capture some output with mode2 -d /dev/lirc0 I ...
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0answers
50 views

Unable to intercept the code of my remote control at 433 MHz with RaspberryPi

I'm trying to reproduce the code generated by my universal 4-channel radio control with RaspberryPI. I cloned my remote with a universal remote like this: I used the libraries included in 433Utils ...
2
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0answers
31 views

PWM on pump not working as expected

I am attempting to run a PWM on a pump using rpi.GPIO using the following code: def run_PWM_on_pump(): gpio.setmode(gpio.BOARD) gpio.setup(8, gpio.OUT) p = gpio.PWM(8, 0.5) #also works at ...
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0answers
124 views

Pulse Position Modulation on Raspberry Pi Zero

I want to WRITE a Pulse Position Modulation (PPM) to an arduino from a raspberrypi. Is the board capable to do this and if so, from which port/pin? A pulse position modulation is a signal that ...
2
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1answer
146 views

What is going on with my GPIO pins?

So I wanted to try out my Raspberry 3B+ once again, but I have been sitting here for hours without even being able to turn on a LED. My code: import RPi.GPIO as GPIO import time GPIO.setmode(GPIO....
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0answers
241 views

Hardware controlled RTS on a Pi4 not working accurately

We need to use RS485 to talk to one of our custom tools. We need to use hardware controlled rts/cts. I've read so many articles about this but nobody ever says it works for them with fast timing and ...
2
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0answers
80 views

How to play a 16-bit WAV in raspberry pi 3 b+ with PWM?

I have a 16-bit WAV file, the header of the file as below: WAV header Information: RIFF : RIFF Chunk Size : 5719002 Format : WAVE Sub-Chunk 1 Information: Sub-Chunk 1 ID : ...
2
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0answers
54 views

Safe cut power supply from raspberry

I want to cut safe the power supply from the raspberry with a relay connected to the gpio. I know how to connect to relay to the board but.. When the relay turn off the power line will be cut off to ...
2
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0answers
28 views

Method for piling three peripherals on one pi

I'm working on my first pi project, which is intended to use the following three peripherals: GPS -- using UART (pinout) eInk -- using SPI (pinout) battery power supply -- using I2C (pintout on p. 15 ...
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127 views

SPI NOR Flash: Unstable reads

So I hooked up an Winbond 25Q256JVEQ to my Raspi3 via SPI (spi0.0) and want to read its content. I use the jedec-nor-spi dtoverlay so its available as MTD. However when I want to read the chips ...
2
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1answer
476 views

Pigpio not calling Callback for first rising or falling edge

I have some sample code (taken out of my larger program) that regularly (but not always) missing the first rising edge: #!/usr/bin/python import pigpio, time def callback(g, l, t): print("Callback ...
2
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0answers
103 views

Issues with Sequent Microsystems 8 relay board

I'm using the Raspberry Pi 3 Model B V1.2, and the Sequent Microsystems 8 Relay Board 2.0. The manual tells you to install this software from github. I installed this and was able to control the ...
2
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1answer
385 views

Pi Camera streaming via gpio

is there a way to transfer the video stream from one raspberry pi to another via gpio pins? One pi is In a closed container with the camera and the other pi drives the user interface. Networking is ...
2
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0answers
124 views

GPIO reading high (because its an input) at boot

I am making a thermostat and one of the issues I have with the pi is that on restart it sets all its pins to input which will provide power to devices, in this case a relay being used to switch on and ...
2
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1answer
71 views

fork() Process Issue on Channel Switching via Rotary Encoder

I have KY040 rotary switcher(encoder) as shown below picture. It is the scenario that there are 5 radio stations(simple html url) in urls.txt which are read into stations list in radyoCS.py, at every ...
2
votes
1answer
485 views

How to connect two cameras to one Raspberry Pi?

I want to use two pi cameras (V2) at the same time for a project. There are a few ideas that came into my mind Creating a camera MUX: 14 pins of the CSI port are connected to a bread board, and two ...
2
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1answer
840 views

UART pins not reading sensor output RPI3

This is my first pi project so im a bit new at this. Im trying to connect a senseair K-30 CO2 sensor to the pi via the UART gpio pins. This is the sensor I am using: https://www.co2meter.com/products/...
2
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1answer
278 views

Button isn't triggering in python script

Software guy here, first time doing hardware. Here is my breadboard setup (yellow is GPIO-8, green is ground): Here is my Python: import RPi.GPIO as GPIO from time import sleep GPIO.setmode(GPIO....
2
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0answers
145 views

Simulating electrical inputs to an Arduino and Raspberry Pi

I have an Arduino-Raspberry Pi system, with many sensors attached, that I want to try to virtually test (without either physical device) on Travis CI. Are there any extant tools capable of simulating ...
2
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0answers
457 views

Change pin for Wake-from-hold

There is this not-so-well-documented feature about shortening Pin 5 (GPIO3) to GND for booting a halted PI (see e.g. here) which is called wake-from-hold. As it is possible to change almost ...
2
votes
1answer
301 views

GPIO is not working

We recently bought two Raspberry Pi 3 B from Cana Kit. We observed that some of the GPIO pins are not functioning properly. More specific details below. We tried to change the state of GPIO pin 7 to ...
2
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0answers
389 views

Can I control 5050 RGB Strips with the Raspberry pi?

I have purchased 5 meters of a 5050 RGB Strip yesterday. I bought it for my PC case, but of course I don't want to use 5 meters in my case. I want to do some smart lighting in my room and a bias ...
2
votes
0answers
285 views

GPIO Edge detect setup on 3 pins, when one changes all callbacks are called

I have a PI setup with 3 sensors (reed switches) and 2 "outputs" to a relay. They are on pins (8, 10, 12) I have pin 3 setup to drive the first relay and pin 5 setup to drive the second relay. I ...
2
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0answers
185 views

Driving a HC-SR04 requires a 10 microsecond pulse, Java does 14. Any success stories?

I'm working on Android Things on an rpi3 dev kit, with the IMHO excellent Picon Zero hat. I'm trying to trigger and read the reply from a HC-SR04, which requires a ~10 μS trigger pulse, then ...
2
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0answers
155 views

Best Way To Power Raspberry Pi Zero and External 4.5 - 36v Circuit

I am creating a drone where I have a Raspberry Pi Zero, and a Motozero. I need to supply the Motozero with power from 4.5 to 36 volts as well as the Raspberry Pi Zero. What is the best way to do ...
2
votes
0answers
227 views

multiple DS18S20 temp sensors without using 1wire

Can anyone tell me if it is possible to connect the multiple DS18S20 sensors to different GPIO ports and pull the temperature on different ports, as opposed to a single wire option where I can only ...
2
votes
1answer
7k views

How to set a GPIO pin to default HIGH before setting it to output?

I have a raspberry pi connected to a Sainsmart 4-channel relay, where each relay is activated by a LOW signal. When I set a GPIO pin to output, it defaults to LOW, which of course activates the ...
2
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0answers
815 views

Unable to change GPIO voltage

I have a Raspberry Pi 3 Model B, running Raspbian. I am using the GPIO pins for a project using PWM to controller a piezoelectric speaker. Everything seemed to be working fine, until earlier today ...
2
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0answers
428 views

GPIO problem. RPIO terminal issue

If I run gpio readall, everything works fine and I see all GPIOs. Terminal: rpio -i 7 Result: root@raspberrypi:/home/pi# rpio -i 7 Traceback (most recent call last): File "/usr/local/bin/rpio", ...

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