Questions tagged [relay]

Electrical device which, when energised by a small electrical current (low-power, control circuit), safely switches a larger electrical current (controlled circuit).

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33 views

3.3v Relay switches on/off/on - off fails 2nd switch off

This 3.3v .relay, link to the the >>> Datasheet As the title mentions works fine until I try to switch it off the second time round, I see the red LED turning on (it looks a touch dim) ...
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45 views

5V Relay only works if VCC is 3.3V

I am very new to all of this, so please excuse if this is a very basic question. I am trying to power a tiny water pump with my raspberry pi. For that I need the 3.3V or 5V output, because the GPIO ...
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43 views

RPi 3 B+, set defaults for GPIO pins on boot and shutdown

I am using Raspberry Pi 3 B+ with Linux raspberrypi 5.4.83-v7+ #1379 SMP Mon Dec 14 13:08:57 GMT 2020 armv7l GNU/Linux to control a set of relays. I set: gpio mode 7 output gpio mode 0 output gpio ...
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60 views

Using Relays to Power off then Cut power to Pi Zero

I have a raspberry pi zero that I am running off a battery for remote logging reasons. There is a low battery shut off module I have connected to the battery in case the battery gets below a certain ...
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90 views

How to detect if an external Relay is ON or OFF

I want to know the state of an external Relay connected to my Raspberry-Pi. Basically if there is current flow or not in A-B. A-B should be connected to R-Pi. I am not sure how to proceed even though ...
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32 views

How to drive two 3v relays safely from Raspberry PI?

I use PI 4 to power two 3v relays. One is controlling 5v dc, another 12v dc. And about once a minute I am switching each relay signal state to On/Off So each relay is connected to 3v pin, ground pin ...
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1answer
66 views

Using GPIO to control 5v relay module not working

so this is my first time trying to use a Raspberry pi and I wanted to automate a motor using a 5v relay module. I'm using a Raspberry Pi Zero W. I am using a 5v 2amp power supply to power the ...
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360 views

Using single 5V relay module (jqc-3ff-s-z) - Asking for help

I have a developer background missing the electronics background. I read some threads with great interest: Using single 5V relay (jqc-3ff-s-z) - safety advice required and 5V relay (jqc-3ff-s-z) I ...
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28 views

Protecting Raspberry Pi from EMI generated from VFD

I built a PCB to control a couple of Industrial contactors and an VFD. The GPIO are categorized, inputs and outputs. The output gpio are connected to the relay system.
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43 views

Raspberry PI and 8 module relay board

I have a raspberry pi 2 and an 8 module relay board (http://nettop.gr/index.php/en/hlektronika/relay/8-channel-5v-relay-module-with-light-coupling-5v.html). Between the relay board and the raspberry I ...
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36 views

DockerPi relay is wired backwards from others?

First off, apologies if I should have posted this elsewhere (such as under general electronics, etc.) I have two relays (JBTek, DockerPi relay hat) I have been experimenting with to control input ...
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199 views

Can you use a 5V Relay Module with the Pi?

Can you use a 5V Relay Module or similar with the Pi?
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66 views

Wiring 12V 5 pin relay (without a module/board) for usage with Raspberry Pi

I'm trying to setup an automated garden as a quarantine project for my mother and I can't really figure out how to properly wire a 12V 5-pin relay module as every tutorial online only shows the ones ...
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131 views

relay switch switches ON but never switches OFF [closed]

I connected my FL-3FF-S-Z two channel relay board to my Raspberry Pi 3, with gpio 0 and gpio 1 (numbers are from to $ gpio readall). Following some guide, as GPIO generates only 3.3v I have removed ...
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174 views

Relay Active HIGH

I am building an irrigation system, and to make it short, I need to decouple the electric-valve to the Raspberry. I am so using the following relay. It works fine, but it is active LOW, for my use ...
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1answer
126 views

5V Relay module working but LED not turning on - How to wire? [closed]

I'm trying to control a relay from Raspberry Pi that will switch an LED on/off. The relay is working (lightning up and clicking), but the LED doesn't turn on. Here is how I wired everything: VCC - 5V ...
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38 views

Raspberry Pi - Activate relay by phone [closed]

I'd like to set up a system to control a relay via land line. My goal is to somehow run a landline to the Raspberry Pi unit and have it trip a relay when the number is called and a DTMF sequence is ...
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1answer
26 views

using 2 pins to power the same relay

I have relay that requires 20mA to operate, which is a bit more than the pi can give from one pin. I as wondering if t was safe to connect 2 GPIO pins together to power the relay. I would use a diode ...
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166 views

How I can control an AC 220v with a relay and a Raspberry Pi 3B [closed]

I'm a newbie in this topics. I love electronics and I love the power of the boards like Raspberry Pi and I want to learn to use it by myself learning in internet, but I have a lot of lacks of ...
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83 views

Problems with the rpi zero and relay [closed]

I Have a problem... (above the relay-coil Datasheet) I want to control a single relay with my pi zero, but it seems that it doesn't have enough power. the 3.3V pin of the rpi (measured to 3.19V) works ...
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396 views

How to turn off relay when RPi shuts down

I have connected a relay to BCM 14 and by setting its output to HIGH I can turn it on, making a 220V bulb to turn on. I use for that the following python instructions: GPIO.setmode(GPIO.BCM) GPIO....
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282 views

How can Rpi python control a 5V relay module, opto-isolated, with a JDVcc jumper? [closed]

Just starting to explore python, Raspberry and a relay. I want to control my 2-channel relay with a button. This is my test code: import RPi.GPIO as GPIO import time import requests from datetime ...
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35 views

Relay is behaving differently from tutorial

Given: Raspberry Pi3 Sunfounder 2 channel relay plugged into 3.3v plugged into ground plugged into pin 18 import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.OUT) GPIO....
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128 views

GPIO Power off on shutdown with retropie

i asked this question before but i have added a diagram to explain it more clearly. I am building a retropie arcade machine with a raspberry pi. I have added a shutdown / startup button to shutdown ...
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131 views

How to cut power to gpio pins on shutdown

I am working on a project where i am using a pi running retropie to make a homemade arcade machine. i have wired and coded a startup/shutdown button. i would like to set up the pi n such a way i can ...
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1answer
125 views

Running pump & servo - Relay needed?

simulate this circuit – Schematic created using CircuitLab So I am working on a project that will require both a servo motor plus a small water pump. Both run on 3.7 -6v and I am going to use ...
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1answer
55 views

no output from 8 channel relay when i run the python script below

# import GPIO and datetime import RPi.GPIO as GPIO import datetime # set GPIO numbering mode and define output pins GPIO.setmode(GPIO.BOARD) GPIO.setwarnings(False) GPIO.setup(37,GPIO.OUT) #Relay 1 ...
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333 views

RPi.GPIO + single channel relay + solenoid lock

I'm working on my first python/hardware project and I want to create a simple (or at least I thought it was simple) cabinet lock, which will lock/unlock when certain RFID tags are approached to the ...
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4answers
95 views

Why is my relay switching on automatically when I start my program?

I'm building a little automated hydroponics system using a raspberry pi zero, a 5 volt relay, a pump and a soil moisture sensor from adafruit. So far everything is working, I can pull the pin to high ...
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1answer
139 views

Process to select and stack a relay HAT and a touch-display HAT

The goal is to design thermostat system via stacking Raspberry pi HATs: Raspberry pi (3B+ or 4) 4-channel relay TFT Touch Display It would be preferable that community experience point out any ...
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1answer
172 views

Relay does not turn off

I am trying to control a 4-Relay module with my Raspberry Pi 4. I tried to do that by writing this script: import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) relais_1 = 8 relais_2 = 10 ...
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2answers
179 views

Use HC-SR04 Distance Sensor and Relay to trigger the Water Pump - Need help with triggering the pump

I am trying to trigger/stop a water pump with the use of a 4-channel relay and a UC-SR04 distance sensor. I tried with some codes but I think I am missing something because although there was no error ...
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2answers
250 views

Multi-threading python function using list and dictionary of GPIO pins cannot activate a relay problem

At the first part of the code(Initializing relays) the GPIO output works as expected, but at the second part it doesn't works, I have break my head for the last four hours trying to find out what is ...
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1answer
152 views

How to make a system that uses a mobile sim and that acts on a relay by ringing the sim

I want to create a system that has an internet connection via a mobile sim and allows owners of enabled telephone numbers to switch a relay by ringing the device sim. The system must be able to ...
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381 views

Rpi3 Home Assistant To Read Signals at GPIO Pins Problem

I'm really new to Raspberry Pi, so please forgive me if this is a noobish question. I have a very simple setup: Raspberry Pi 3 running Home Assistant with a switch connected to GPIO12 and 3.3v. The ...
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215 views

gpio turning on/off relay, seems backwards

I have a Raspberry Pi 3b and wired to a 4 port relay I got from Amazon: https://www.amazon.com/JBtek-Channel-Module-Arduino-Raspberry/dp/B00KTEN3TM/ Everything is working, but it seems backwards to ...
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29 views

Powering solenoid from batterypack

Im trying to power my 6V solenoid that is connected to my 8 channel 5V relay using my 8 x AA batterypack. The pi is being powered through an adapter and the relay from the VCC to 5V pi. When the LED ...
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899 views

how do I automatically power off the raspberry pi and cut power every night and then power it back on each day?

Background I'm a student working on research project to develop a remote wireless sensor network of data loggers. Each data logger (aka node) is going to be retrofitted to a bird feeder that reads ...
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123 views

using Pi Zero W GPIO relay control

I am trying to control my relay with Raspberry GPIO. Using the terminal to write to gpio5 (Physical 18, BCM 24) works: gpio mode 5 out gpio write 5 1 Trying to do the same in my c++ code doesn't ...
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1answer
150 views

12V Solenoid with Relay doesnt trigger

So I am using 8 AA 1.5V batteries that is wired to my 12V 16 channel relay which is wired to my Rpi. I want to be able to control 16 solenoids and use the relay as a switch for the solenoids. As far ...
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76 views

Relay modules: Can I switch AC in one and DC in another?

I would like to control both 120VAC and 24VDC from my RPi 3B+. To make this easy, I'm looking at one of the various 3ch or 4ch relay modules for an RPi 3B+, like this or this. I'm familiar with using ...
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238 views

External power supply to a relay controlled by a Raspberry Pi

I am a beginner to relays and Raspberry Pi so please pardon me if my question sounds naive. I am trying to control 4 DC motors using relays and raspberry pi. I have decided to use an external supply ...
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1answer
216 views

I think I fried my Raspberry Pi, but I'm not sure

I was making connections from my Raspberry Pi to a relay module. While I was running some sample code, I noticed that after I had terminated the program I was still getting a high CPU usage (around 60%...
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Rpi GPIO Controlling 5V Relay Problem

I am working on a project that requires a camera analyzing some images and activating the appropriate GPIOs to control a relay board. I currently have a touchscreen display, a Raspberry Pi Cam ...
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1k views

Rpi UART control IR Remote HDMI switch problem

I've been reading about how to use the GPIO to toggle a button on a thing I've taken apart. It's like this: Amazon I watched a video of a guy using an opto-coupler, what are the basics here? I'm ...
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3answers
78 views

Voltage dropped significantly on GPIO 4 with a relay coil

I have a Raspberry PI 3 B+, and when I activate the GPIO 4 as output and checking agains a multimeter I get its 3.3V as expected. If I connect the GPIO4 to one end of a coil (http://www....
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1k views

Driving 12V/24v Relay from raspberry pi

I am trying to drive the 12V/24V relay using Rasberry pi 3. I have got schematic from one of the forum.I have question related to below schmatic. 1) The ckt build to drive 5V relay . How can use ...
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173 views

Is 5V out on the Pi Zero W unregulated?

I want to power a 5V relay breakout board from a Pi Zero W. I believe the 5V pads are "raw" and a "pass through" voltage? Is this correct?
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2k views

Wiring a 4 channel relay - is this possible?

After watching many videos and reading, I think I now know how to wire a 4 channel relay to control 4 12V DC Solenoids with my PI. The Solenoids are wired in parallel. Please see picture 1. However,...
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343 views

Is a RC snubber required when using the pi with a relay?

I am hoping to use raspberry pi to switch on and off a heating lamp and an aquarium pump via a relay switch. Both devices are plugged into 120V AC normally. The relay tutorials online seem to be ...

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