Questions tagged [signal]

Use this tag for any question involving types of communications . Generally at the hardware level such as electric voltage levels or light colors. Modulation is a key component of data signaling, but the mere presence of a voltage can signal availability of a device.

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gpiozero and signal

My python script waits for motion (with gpiozero MotionSensor wait_for_motion()) most of the time. But it also needs to react to SIGUSR1. The problem is: when SIGUSR1 is received wait_for_motion() is ...
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Problem with reading GPIO input value - photoeletric sensor

Good night! I've got some problems with GPIO input values in my code (Python). I'm using a Raspberry Pi model 3, and RPi.GPIO as GPIO module. I'm tring to get the signal values of a photoeletric ...
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How I can transmit data from soil moisture sensors 10m away to raspberry pi?

I found this interesting project: https://hydrosysblog.wordpress.com/hardware/ And I want to apply a soil moisture sensor. But the sensor may be 10m or more (but less than 20m) away from the raspberry ...
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Monitor I am using is keep showing input signal out of range. (Raspberry-pi4) How can I fix it?

I am currently connecting my raspberry-pi4 to Hanns.G monitor. The monitor's display looks fine just except the message about INPUT SIGNAL OUT OF RANGE. This message is located at the center of my ...
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Trying to plot the ADC values from the PICO similar to what an oscilloscope displays. Just scrolls to the left right now. Total Python newbie

#!/usr/bin/python #Python 3.7.3 # Attempting to plot the ADC values coming from the PICO # Program contains only necessary lines of code for testing plot routine # The Raspberry PI Pico is connected ...
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I would like to control my Traxxas Stampede with a raspbery pi

So i want to make basically a glove where when i tilt my hand it will turn the car. (I'm going to just have simple buttons for forward and back so I only need to focus on one tilt plane) I plan on ...
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2 answers
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What is the maximum baud rate achieved in raspberry pi 4b

What is the maximum baud rate achieved in raspberry pi 4b for serial communication? I want to use RPI for communicating with PC(win, linux),Want to acheive maximum speed through USB communication. I ...
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Receiving noise signal on input pin after connecting jumper wire to GPIO pin Raspberry pi 4

I am trying to use GPIO pin to get input from the sensonr, after connecting the sensor I noticed I have a lot of noise ( fluctuating signals between 0 and one). After further troubleshooting I noticed ...
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GPIO configured as interrupts detects noise of the engine even if isolated

Did anyone work with a Raspberry Pi in a an automotive project ? I am working on creating a dashboard for a motorcycle and it is making me crazy! when configuring a GPIO pin as an interrupt it ...
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Transmitting a signal without an external transmitter [closed]

I found a repository called rpitx which can be used to transmit a signal (e.g. the signal of the keyfob of my gate). I'm wondering how this is possible without an external transmitter connected to the ...
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How to use 2 GPIO pins for 3 buttons

I am using almost all the GPIO pins on a project so I had to be resourceful when adressing the pins for the buttons. But I just can’t get it to work. I don't know if something is wrong with the code ...
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What is going on with the Raspberry PI SPI? Weird jitter in signal

I'm using python and spidev to do spi transactions over the Raspberry Pi's spi channel. I'm having a couple of different things happen that are not what I am expecting. This is a capture of a spi ...
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Raspberry pi4 + ADC

I have been working with Raspberry pi 4 to acquire analog signals. I get AD/DA High Precision Board by Waveshare (ADS1256 A/D) to convert analog input and I downloaded python source code from ...
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Real time + High frequency ADC data reading with Raspberry Pi 4

I need to acquire a signal at a minimum sample rate of 10 kHz and processing it real-time using a Python code. Since Raspberry Pi only reads digital signals I get an ADC (High Precision AD/DA Board ...
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Sending a NEC like signal via a GPIO

I'm trying to control an existing LED strip controller with a Raspberry Pi. The controller has an IR receiver to receive commands. I removed the IR receiver of the controller and added a connection to ...
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Waveshare AD/DA espansione board setting sampling frequency

In order to acquire 3 analog signals with Raspberry pi 4 I want to use ADS1256 Waveshare's AD expansion board ( 8 channels single-ended, 24 bit). I was wandering if there's a way to set a different ...
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GPIO 3.3 V signal still readable after inputting high resistance values

I recently obtained a raspberry pi 4 (8GB) and I am trying to understand the GPIO behavior and ran into an event that I don't understand. I have set-up a simple script that allows pin 36 (GPIO 16) to ...
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Monitor only recognises the signal when started first

My monitor, an old Toshiba 47wlg66, will display what my boards output (whether it's my old raspberry pi 1 A or new raspberry pi 4 B) only if it was powered first. Otherwise it will remain black.. It ...
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Connecting Raspberry Pi 4 to old VGA monitor

I'm trying to set up an old monitor to use with my Raspberry Pi with Ubuntu 20.04, but whatever options I try, my monitor doesn't detect any signal coming from raspberry. I have original HDMI cable ...
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High-precision time-varying PWM outputs on R Pi

I'e seen a lot of examples of simple PWM on the Pi where relatively high-precision PWM signals at a fixed duty cycle can be generated using WiringPi or pigpio in hardware PWM mode. I have tried ...
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Monitor not recognized by other devices after having connected my raspberry pi 4

I have a weird problem and I simply can't find any solution to it: I use a Fujitsu Siemens monitor with a dvi to hdmi cable which works just fine with all my devices. However, after I connected my ...
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1 answer
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PedalPi, lag when piping in data

I am modifying a pedal pi (link here). I split the input program from the output program. For simplicity right now, that all it does. The standard out from my input program is being fed to the ...
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2 votes
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Interpreting voltage output on ADC with rated AC current sensor

I know I have asked similar questions before, but I have switched sensors and encountered interesting results that I do not understand. Purpose: I intend to use an AC current sensor to measure ...
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2 votes
0 answers
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HDMI No signal on one tv but signal fine on another

I am using a pi zero w. I have used it on two TV's to date. It's been a month or so since I last used it and now it works on only one of the TV's. This wouldn't be a problem but I am giving this to ...
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Interpreting 10-bit ADC output

I am having difficulty understanding the output from my ADC. I am using a 10-bit MCP3008 with a photoresistor and CT current sensor connected into the analog inputs. I am reading the signals with this ...
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1 answer
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How to enable sending keyboard signals while in SSH?

When I use a keyboard plugged into the pi directly, I can send signals using ctrl+T / ^T to get messages from ongoing commands in terminal. When I'm logged in via SSH on my mac, I seem to lose this ...
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2 votes
2 answers
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Broadcast VHF or UHF to CRT TV

I picked up this TV and thought it may be fun to use it with a Raspberry Pi. https://www.cnet.com/products/spectra-52-bw-5-crt-tv/ However, I soon realized the only way to get a video signal to the ...
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2 answers
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How can Rpi read ADS1256's negative values?

I'm using this Raspberry Pi High-Precision AD/DA Expansion Board from waveshare. I have some questions regarding its ADC (model name: ADS1256) unable to give out negative value. Specifically, only ...
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2 answers
552 views

Raspbian Stretch lite doesnt send HDMI signal on second boot

I have installed the most recent Raspbian Stretch lite (release: 2018-11-13) to a SanDisk ultra A1 micro SD card to use it for my Raspberry Pi model 3B. I connected a HDMI monitor and a USB keyboard ...
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Generating signals with Pi

I have a vector of 500 numbers and would like to output these at a sample rate of 1kHz, thus a signal time of 0.5seconds. Is there any way to do this using a Pi? Do the GPIO pins only allow for an On/...
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Python script wait for button press before starting/stopping a separate python script

I've written a python script (shown below) which starts and stops another separate python script (datalogger) once a button is pressed. The datalogger script records logic levels (0 or 1) and stores ...
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2 votes
1 answer
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How to start and stop python script using button

I've written some python code that should start and stop another python script (Datalogger) when a button is pressed. So when the Pi is booted up I'm wanting the button script to run and then once I ...
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1 vote
0 answers
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Data acquisition using DSO 2150 (Hantek, Virtins, etc.) in Raspberry Pi

I have Virtins 2815H which is a DSO based on DSO 2150, I would like to real time record a signal around 1 MHz using it and process it in Raspberry Pi. I have searched a lot about the data comm from ...
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2 votes
3 answers
1k views

GPIO relay signal cross turns to all relays staying on after Darlington added

I have 4 Sunfounder 2 channel relays 7 of which that I'm using to control some things on my aquarium. I suspect that I may have wired them up wrong somehow though. The behavior I'm seeing is as ...
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GPIO.wait_for_edge and signal.signal()

I have the below sample code that is trying to implement a safe shutdown mechanism ( yet to fully implement) For some reason, I am not able to catch any signals using the registered signal handlers. ...
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Changing RPi version may lead to binary corruption?

Apologizes for the object, but I cannot easily summarize the scenario. I created an sd-card based upon Raspbian Stretch Lite, with some customization. Then I cross-compiled Qt5.9 and copied the ...
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1 answer
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SignalR on Mono Raspbian

Had tried to launch SignalR client (.NET Framework 4.5 target) on my Pi 3 with Mono on Raspbian. But it's not working because SignalR's throws a System.InvalidProgramException - something wrong with ...
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Send and receive 868Mhz signals with my Pi

My home lighting is achieved using wireless Delta Dore switches working in 868 Mhz. Here are my switches reference : https://www.deltadore.fr/data/product_files/6351091/documents/notices/Util/fr/...
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2 votes
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Raspberry Pi + Windows 10 IoT Core + RS485

Has somebody ever worked with windows 10 IoT Core and used RS485? I would like to receive some signals from the RS485 device. I would like to do this with Windows universal app.
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2 answers
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Raspberry Pi no signal to hdmi

This is the first time I've tried to use a raspberry pi, I bought a CannaKit that came preloaded with NOOBS. When I attempt to boot with the HDMI my screen says no signal, the HDMI output is correct, ...
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5 votes
1 answer
9k views

Control signal strength of Raspberry Pi 3 WiFi signal down to minimum

With the Raspberry Pi (latest Raspbian OS) configured as a WiFi Access Point that gives internet access through ethernet interface, I'm doing some WiFi Signal Strength testing. In reduced space to ...
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Square wave generator using RPi 2

I am completely new to this and I am not into programming. My requirement is to generate a 965Hz precise square wave. This frequency may need fine tweeking from 955Hz to 975Hz depending on other ...
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Minimum TTL 5.0V signal duration

I'm working on a little project in my physics lab. We would like to create a photon coincidence counter. We were thinking to use the Pi GPIO pin to monitor a couple of photo diode which produce a 15ns ...
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Can I use the Ethernet (RJ45) port on the RPi to place telephone calls?

I would like to use an RPi as an analog landline, and was wondering if instead of having to use a serial port to connect a modem that generates DTMF, if the Ethernet port could be used to generate ...
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5 votes
2 answers
713 views

How to find distance and direction of IR signal?

I am wondering where I should start in trying to get my Raspberry Pi to detect the distance of an IR signal and the direction of it. Has someone already done something similar? The end goal is to get ...
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Listen to 433MHz signals in the background

How can I listen for 433MHz signals in the backgrounds from boot on? I am using this receiver / transmitter pair here. An Arduino sends signals to the Raspberry Pi and I want to listen for them in ...
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How to show audio signal on the screen of raspberry pi? and how to input the sound signal? [closed]

The screen i used is http://www.amazon.co.uk/Touch-Screen-Designed-Raspberry-Model/dp/B00UV78E9Q/ref=sr_1_14?ie=UTF8&qid=1432902157&sr=8-14&keywords=raspberry+pi+2 I would like to know how ...
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IOError exception not handled within signal handler

I am usig a RPi as a datalogger for an accelerometer, the ADXL345 breakout from Sparkfun. Since I need the accelerometer to sample at an exact frequency of 200Hz, I am using a signal to trigger the ...
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1k 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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Import composite/ntsc-signal

I already googled a lot and mostly read that importing composite Signal to the Raspberry is almost impossible. I would just take a webcam and proceed since it seems to be a lot easier. The problem is,...
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