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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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How to hook up multiple devices with sda pins?

I am building something with raspberry pi. I am using the 16x32 led matrix as well as the port expander (MCP23017). Both use the SDA and SCL pins. I am having trouble hooking it up. I realize this may ...
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How to attach Air208 GSM micro sim card board to raspberry pi zero w that already has display attached on GPIO

I have a Air208 GSM micro sim card board that I want to attach to my raspberry pi zero w to make calls. The issue is that I already have a 3.5" tft display attached to the pi zero w via GPIO (header ...
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1answer
24 views

Connecting jumpercable to gpio pins

My teacher gave me a large group of jumper cables attached to one another. this might be a stupid question but if it's attached like on the on the bottom picture what is the order of the cables? (...
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1answer
37 views

Controlling LED strip from GPIO Help?

I have a ws2811 LED strip that I was powering using an arduino, but I want to do some more complicated things with it, and figured my old raspberry pi would be perfect. So I followed a tutorial online ...
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1answer
441 views

Use Adafruit Motor HAT and GPIO

How can I use the Adafruit Motor HAT and RPI GPIO at the same time? I just need an extra tall stacking header, or there is something I missing? My goal is use the Motor HAT and some LED and HC-SR04 ...
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1answer
21 views

gpio command from terminal

I have two simple scripts, one in Python, one in bash to turn on and off a LED. I don't know what I'm doing wrong but if a run the bash script nothing happen, while the Python script It works flawless....
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1answer
34 views

Raspberry Pi IO issue (Python)

I am testing my Raspberry Pi IO pin because I realize some of my IO pin is not functioning. So I wrote this python program to test all the IO pin import RPi.GPIO as GPIO import time GPIO.setmode(...
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3answers
48 views

Input on GPIO at very Fast Speed

I am getting a signal at 1 GPIO which i need to read at an interval of exactly 10^ (-6) seconds. I am using wiringpi.h in C and the issue is that digitalRead() also takes some time thus i am not able ...
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1answer
42 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 ...
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2answers
387 views

How Much Current for GPIO Power Supply?

I'm working on an audio project where the Raspberry Pi will be powered off the GPIO. I was trying this using an LM7805 voltage regulator to get 5v from the 9v power supply that is standard in a lot of ...
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1answer
62 views

Reading Output signal from external circuit using Rpi GPIO Pin

I am trying to read a signal coming from an external circuit thru the use of raspberry pi's gpio. the signal I am trying to read is a 3.3V signal coming from a voltage divider circuit. this circuit ...
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32 views

File transfer between raspberry pis via GPIO pins

I'm trying to send image(3MB) captured by one pi to another pi, external WIFI or setting up one pi as AP is not possible due to strict regulations, all I can use are the two wires. Currently I'm ...
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1answer
2k views

GPIO doesn't work, error: “Error when trying to open pin 11”

I connected a LED to pin 11 as per this guide. And this works in the terminal to turn it on and off: gpio mode 0 out gpio write 0 1 gpio write 0 0 But when I try to use pi-gpio, with this code as ...
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1answer
31 views

Blink project mishap, help?

So I've set up the blink experiment using my newly bought electronics kit for my RPi 3B+ (https://www.amazon.de/Freenove-Raspberry-Processing-Tutorials-Components/dp/B06VTH7L28/ref=sr_1_3?ie=UTF8&...
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1answer
27 views

Pigpio reading sensor returning -83”i2c read failed”

I am testing using my new air quality 5 click sensor with my Raspberry Pi (https://www.mikroe.com/air-quality-5-click) using command line. When I enter i2cdetect -y 1it appears at address 48. Then ...
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1answer
459 views

sh: can't access tty; job control turned off

Yesterday, I was programming GPIO controls for a robot in class and left for a few minutes to work with another group. I came back to find all the GPIO disconnected and sh: can't access tty; job ...
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1answer
57 views

I can't change pin value

I've been with my new Raspberry for a month and it worked perfectly but today the pins have stopped working. I have tried many ways to put them with value 1 but for more I try not change them from 0. ...
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2answers
219 views

I want to run a Python 3 script on startup and in an endless loop on my Raspberry Pi

I have created a smart vending machine using my Raspberry Pi. For now, I open the Raspberry Pi using SSH and run the script manually for every transaction. I want to automate the process and run the ...
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1answer
39 views

Can't get HC-SC04 Sensor to work

I'm using a Pi Zero W with a soldered project board to interface two ir Sensors and trying to make an HC-SR04 sensor work. I'm using the 5v supply to power all three sensors. I've set up a Motion.py ...
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1answer
428 views

Listen for certain keyboard input and insert to SQL Server DB

I have a USB NFC reader (acts as an emulated keyboard that types out the 10 digit ID number on the card when scanned). I want an app to listen for this input and when it sees 10 digits, I want it to ...
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1answer
364 views

Access the display from a python app running as a service

Problem: The code below can't access the display when running as a service. I have my raspi hooked up to a touch screen monitor in the kitchen and I've attached a Passive Infrared sensor to the GPIO ...
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1answer
4k 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 ...
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Scada for Raspberry Pi - prices? [closed]

Do you have any experiences with SCADA solutions for Raspberry Pi? I want to find optimal solution, where is balance between number of tags, stability, functionality and price. Let me know, if you ...
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1answer
393 views

Controlling Ground Pins on a Raspberry Pi zero

I am attempting to make an LED matrix such as in this tutorial: http://www.appelsiini.net/2011/how-does-led-matrix-work. Is there any way I can control components being grounded whilst keeping as many ...
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2answers
2k views

Adding microphone support to the RPi 3B

I own a Raspberry Pi 3B and want to extend the sound capabilities. So what I need is sound output for speakers and headphones via a 3.5mm phone jack. In addition to that, I want to add an internal mic ...
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3answers
69 views

Problem controlling LED on GPIO3

I need to add a status led to my pi zero w and after taking a look at the pin out I decided to put an led between pin 5 and 6. Please see attached picture. I soldered a blue 0805 SMD led directly on ...
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4answers
27k 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 ...
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1answer
452 views

Node-Red Raspi GPIO: Using only rising trigger

When using node-red with raspberry pi 3 GPIO, node-red will send a message, every time the state changes (= rising and falling trigger). Is it possible to only send messages on rising trigger? Using ...
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0answers
14 views

How to get maximum GPIO output speed in Kernel module?

I'm writing a Linux kernel module on RPi2 to push an array to RGB Led matrix, so I want to have maximum speed of GPIO to reduce the 'flick' when it run Bit Angle Modulation. According to this site, ...
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1answer
3k views

How can I send AT commands to raspberry pi 2 serial uart ble module from python script

Ive connected an hm10 ble to my raspberry pi 2 GPIO pins (3.3V, GND, Rx and Tx). I've changed the cmdline.txt to 9600 and the inittab is empty. I downloaded raspbian about 1 week ago. Im running ...
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0answers
18 views

Issue with controlling GPIO via Flask web app

I am currently building a project in which I am using a Flask web app to control various different components with the pi's GPIO. The issue i am currently having is stopping the execution of code that ...
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22 views

Build/Buy 128 Button Matrix

I want to build a system where roughly 100 Buttons can be pressed and start a specific command. Pricecly I want to digitalize a good old Piano, at least as good as possible. As far as google led me ...
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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 ...
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1answer
1k views

GPIOZero button not working

I've been getting into GPIO recently with the GPIOZero library but when i first tried it today it completely failed. As my first foray into GPIO i set up a circuit to light up an LED with the push of ...
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1answer
60 views

Connecting several (roughly 100) Buttons to the PI (USB?)

I havent found anything, but iam sure there is already info on the topic. So even just a link would be helpful for me. I want to build a Jukebox. So pretty simple. Around 30 Buttons, if Button is ...
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1answer
348 views

PWM via GPIO to trigger a MAPIR Camera

I am currently trying to trigger a MAPIR NDVI Camera with a PWM Signal. The camera is connected via this HDMI trigger cable. The white wire is connected to GPIO PIN 17, the black wire is connected to ...
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2answers
85 views

Connecting 32 magnetic sensors

I would like to build an organ pedal board and use Raspberry Pi as signal processor. The pedal board will have 32 inputs, one for each key. I am planning to use magnetic sensors (like A3144), which, ...
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2answers
1k views

Use GPIO to trigger button press in software

I have a ceiling fan remote that I want to control using the Raspberry Pi. Instead of sending RF signals or buying a Wi-Fi wall switch to do any of this, I'd like to use an existing RF remote and ...
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1answer
1k views

Problem with ESC, brushless motor and Raspberry Pi

I have connected an ESC (an electronic speed control) with a battery and a brushless motor. The Raspberry is connected to the ESC to control it. I know - when I turn on the program that is on the ...
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0answers
1k views

Analog Microphone with Raspberry PI

I have an analog microphone like this one : Is there a way to record audio from GPIOs and convert it to readable format, such as .mp3 or .wav ? I searched on Google, but I didn't find what i want .....
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1answer
1k views

GPIO event handler triggers off rising and falling edges

I'm trying to set up a tachometer. I used a comparator IC to get a real clean signal on pin 21 but I'm getting iterrupts on the rising AND falling edges. #!/usr/bin/python3 import time import ...
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1answer
2k views

How to set dtoverlay @ config.txt?

No.1 - I have one rasperry pi 3 where hyperion (ambilight) is running. No.2 - And one rasperry pi 3 where I have an IR transmitter (with lirc) for sending commands to the tv. I need to have both ...
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1answer
406 views

Error when sending second start command to Cylon.js to blink LED

Using Node.js, express and cylon.js, I'm getting a post request and blinking an LED using a raspberry Pi. I receive the first post request fine, the code runs and the LED blinks. However on the second ...
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1answer
40 views

Risks of powering short LED strip directly from GPIO

I am trying to understand the simplest ways to power a short LED strip of 30 WS281x lights. Most of the instructions I’ve found mention using a separate power supply for the LED’s, but is it ...
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2answers
666 views

Mulitple Input state changes/event detection

Picture 1 shows my setup. I connected the RPi3 Input parallel to an I/O terminal. The inputs are connected to a pull down resistor setup. Pictures 2 and 3 show the setup more in detail. Program-> ...
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2answers
166 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=...
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1answer
2k views

Kodi on a GPIO screen

I recently bought a 3.5 inch TFT touchscreen connected by GPIO to my raspberry. I finally managed to make it work with Raspbian. however, when I launch KODI, the image on the TFT freezes and KODI ...
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1answer
552 views

Using gpio from CLI to trigger a rising or falling event detection

I have a python system script with various functions. I have multiple buttons hooked up to the Pi and I am using this code: import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(22, GPIO.IN, ...
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1answer
441 views

RPi.GPIO not working at all

I have just started with the GPIO on my raspberry pi but can't get any of the code to work. import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setwarnings(False) GPIO.setup(18,GPIO.OUT) ...
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1answer
628 views

PWM object's ChangeDutyCycle method is not working

I have a motor class but I dont' know why this motor cannot change speed class Motor: def __init__(self, pos, line_status=0): def set_motor_gpio(_a, _b, _pwm): self._A = _a ...