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Questions tagged [relay]

A relay is a part that acts like a switch that can be controlled by an Arduino. They usually are powered by sending current through a coil, which moves a piece of metal to touch a contact within it. (Note there are also solid state relays which act more like a transistor.) The moving parts is why some devices make a "clicking" noise when they turn on/off a light or another device attached to it.

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Wemos Relay Shield Confusion [on hold]

Using the ESP-RFID repo on GitHub, I've flashed a NodeMCU and am able to access and configure it to work with the RC522 RFID reader. What I'm struggling with is how to connect the NodeMCU properly to ...
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0answers
22 views

12v relay using arduino [duplicate]

I want to control a 12 V relay using an Arduino 5 V signal, but due to some unknown reason the relay does not work. I am using a BC548 transistor as a switch for relay.The relay only triggers when I ...
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1answer
43 views

12 V relay using Arduino [on hold]

I want to control a 12 V relay using an Arduino 5 V signal, but due to some unknown reason the relay does not work. I am using a BC548 transistor as a switch for relay. Please suggest where I go wrong....
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20 views

Voltage to keep my board safe

I have recently made a home automation system using node mcu and relay module and i am powering both together using my 5V ,2A dc adapter and i am scared that if I'll keep using it for very long hours ...
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3answers
65 views

How to initialize digital output pin as low

I need to define a pin as output for relay module but when i do it in setup section, relay is activated (low - 0) automatically then i deactivated immediately with coding digitalWrite(pin, 1) but this ...
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28 views

Stuck Arduino Relay?

I am looking for a relay which stays on/NC (Normally Open), and when I send a new signal switches to off/NO (Normally Open). So the relay doesn't consume any power while being in a specific position. ...
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1answer
48 views

Do all pins of Arduino Uno output 5V?

I am currently working on a project which uses PIR motion sensor and 5V relay. Since you might be familiar that both the motion sensor and the relay requires a 5V connection. My problem is, I don't ...
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2answers
83 views

What is the state of Arduino pins when the arduino is unpowered?

I'm building a control box to provide logical control of power outlets. I'm using a 4 channel 5V optically isolated relay system to control 4 separate outlets. To use optical isolation you connect ...
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1answer
49 views

Replace mechanical switch with electrical switch or relay

I have a remote controller for a portable heater, and working on a small project to be able to control the fan on/off from an arduino with Bluetooh HM-10 module. I thought a solenoid might work by ...
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3 views

Using Relay Module [migrated]

I want to know whether I can use a relay module to switch on & off a door alarm (1.5 v * 3)? Basically, can a relay switch work in this low DC power? Also, I'm trying to make an alarm system ...
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1answer
33 views

How do I use a 5v/120v relay that is not mounted on a board [closed]

I bought an arduino kit, and it came with, amongst other things, a 5v relay to control 120-220v. The relay is only that, there is only the 5 pin relay, and it's not on a board on which one can ...
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1answer
48 views

Failsafe Arduino

I want to read an RFID tag using an Arduino, which controls some relais. This is easy. For me the more complex part is to build it fault-tolerant. So I thought I could use the watchdog. The tricky ...
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1answer
66 views

5V 10A 4 channel relay to 2 lights15W light in series in 220V AC supply

I am trying to setup my first relay module with live environment. I have attached the relay module image below. Which I am using to control 4 devices in my switch board as follows: Fan (working ...
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2answers
87 views

Is it okay to short IN and GND pins of relay module with controller ground? [closed]

I have this relay module that is attached to an ESP8266 (Wemos D1 Mini). Currently, I operate the relay by shorting the IN and GND pins to ground (relay module uses low state to energize) with a ...
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0answers
31 views

Garbage output/ not running at start up nodemcu

I have a nodemcu acting as a thermostat home office. The wall heating element is controlled with a solid state relay on D2. If i have it connected, I cannot program the board from the arduino ide. I ...
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1answer
23 views

Relay 24 V appliance [closed]

I want to use a switch and an Arduino to "power" a 24 V DC appliance and I am not really sure what relay to use for this. So I need the relay to be able to switch it on and off, but I have not really ...
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0answers
124 views

Wemos D1 mini with relay shield (why does D1 not operate relay but D5 does)?

I connect gnd>gnd, 5v>5v and d1>d1 - nothing works with relay blink code I change connection to d5 on wemos (still d1 on relay) and it works fine with code change to d5 Any ideas, as at present I ...
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1answer
62 views

Digital Input using a button doesn't work properly when using it to control a relay

I'm trying to control a relay both via Bluetooth and using a switch. The problem is that, when the LED is off, I can turn it on with the switch but then if I turn off the switch the relay will stay on....
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1answer
74 views

nodemcu esp8266 does not boot up when 5V pin is connected as a VIN source

Whenever I boot up the esp8266 or flash code via usb ,I have to remove vin pin otherwise it does not boot up. If I remove vin pin then flash and boot up happens and then i am able connect vin with 5 ...
2
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1answer
56 views

Newbie question - Biltong Box Project [closed]

I am a newbie to electronics, but I do have experience working with electrical wiring in the UK, so I am comfortable working with 240V reasonably safely. I have also built a camper including all the ...
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1answer
70 views

Using mills() in place of delay() on relays not getting solid switch over

I know I should post some code that maybe cleaner but really I am just in need of a answer to a problem I seem to run into a lot when using mills() in place of delay(), whilst making a Christmas light ...
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2answers
64 views

Voltage Regulator getting too hot

I have an Arduino mega that is being used to control relays and ultrasonic sensors. The relays that I am using is a 4 DPDT Signal Relay Module Model: D-256 Series and the other is a 4 channel Single ...
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1answer
308 views

Arduino UNO + ESP8266 WiFi Relay by LC Technology

I have Arduino Uno, and recently obtained ESP8266 WiFi Relay by LC Technology. I tried to look up some information about that on the net, but all the answers / suggested solution didn't work for me. ...
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1answer
70 views

esp8266 + octocoupler relay: WDT reset when using AC current

I'm trying to switch on bulb via 4 channel 5V optocoupler relay controller from ESP8266 using WIFI Access point. All my connections looking fine and i can able to connect WIFI SoftAP and send signal ...
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1answer
107 views

Shift register with relay board behaving erratically

I have a nodemcu connected to a shift register(https://www.amazon.de/gp/product/B07CHBYR7Z) to control an 8 channel relay board (https://www.amazon.de/Elegoo-Relaismodul-Optokoppler-Arduino-Raspberry/...
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2answers
66 views

8relay module asks more than specs

I have a 8 relay module that should use not more than 20 mA per relay. Altough when measuring it asks around 70. If I use 6 relays, that would be more than an Arduino Mega can give. (I already lost 1 ...
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1answer
110 views

Frequent ON OFF in SSR

I am working on a project on Arduino OLED MAX6675 thermocouple and SSR for my oven. My problem is when my SSR goes in LOW or HIGH state it turn ON and OFF several times before going to permanent HIGH ...
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1answer
67 views

Are these relays connected correctly?

I currently have limited electronics experience. I am planning to use mains power through relays for climate control, so considering the risk, I would like to check to see if these relays are ...
1
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1answer
65 views

How to detect when intercom is ringing?

For my apartment, I need to check when intercom is ringing and call an API in that case. I was thinking about using an AC input / DC output relay, since the buzzer signal is an AC signal. Is there an ...
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2answers
207 views

shift register 74HC595 enable specific pin

Its driving me crazy for some couple of days now and i don't get the answer. I'm busy to setup a irrigation system with a shift register 74HC595 and a 8 channel relay board. I see a lot of sketches ...
2
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0answers
48 views

Project: Relay is ticking, but not actually switching [closed]

I'm trying to make an automatic planter for herbs etc. I finally got everything 3D printed and wired together. But for some reason, the relay I'm using refuses to switch or enable certain connections. ...
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0answers
58 views

Correct wiring?

I'm doing some Home automation and am currently trying to automate my intercom system. My overall aim is to be able to detect when someone has pressed the buzzer and then to be able to open the door ...
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3answers
83 views

Monitoring the state of AC relay, design considerations

I want to use a sensor and relay as a safety device to allow/deny power to an AC mains-powered electrical unit. If the wall power is disconnected I loose the state of the relay which is stored in a ...
-1
votes
1answer
129 views

Relay Module for water pump [closed]

I want to switch on/off my water pump by using arduino nano, I have 2 channel relay module. Is this module safe for controlling pump? Specifications pump: power = 746 watt (1HP) single phase, voltage =...
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3answers
480 views

Push button control of multiple relays

I'm new to arduinos and have not been able to find/create a working bit of code for my project. I'd like to control several different relays (standard 5v optical relays) with push buttons. I want one ...
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1answer
393 views

Problems with NodeMCU and Relay

I've connected the MCU to a cheap chinese 24/12v to 5v car phone charger and hooked some wires to a relay.When I try to program doesn't matter if the pin is set to high or low , as soon as I touch the ...
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3answers
141 views

Can multiple Arduinos be connected to a single relay?

I have a 16 channel relay that will basically manage 16 different contacts. However, each channel in the relay needs to be controlled by an individual Arduino. So in total I would have 16 different ...
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1answer
63 views

Safely powering a relay from same source as attiny/arduino?

My project involves using ATTINY to control a 5v relay (specifically JZC-11F and will be ground triggered) in an automotive setting. I keep seeing the warnings of powering a relay from the same ...
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2answers
19 views

Relay does not trigger

Its my first attempt to work with relay I tried to test my relay with this simple code int Relay = 2; void setup() { // put your setup code here, to run once: Serial.begin(115200); pinMode(...
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2answers
366 views

5v relay module

I'm using NodeMCU with 5v relay module. my problem is that when the output of NodeMCU is high the relay is off. Which means that the relay module work in an inverted way so how can I treat this issue ...
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3answers
106 views

Touch Sensor - Determining Pressing/Hold Length and Modifying Program Flow Accordingly

The code below is used for controlling a relay with an Arduino. Pressing the touch sensor connects and disconnects the relay. If the user presses/touches/holds their finger on the touch sensor for ...
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1answer
292 views

Arduino Uno Motor control using 2 Relays, 2 Limit switches and Bluetooth. Forward Reverse Stop

Modified existing project from this link: Problem : Trigger limit switch to stop DC motor I modified this code to control two relays which are wired to motor poles for Forward or Reverse movements ...
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1answer
79 views

“Active LOW” relay board Pin configuration [duplicate]

I bought a 5 V Relay Board: LINK (Aliexpress) and just realised it's "Active LOW". I want to control a water pump via a Arduino Micro. I tested it and as far as i understand the workings of this ...
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votes
1answer
230 views

Controlling two-pole contactor using Arduino [duplicate]

I am working with Packard C230C contactor to develop own EVSE. For a simple start i just want to toggle contactor using Arduino. OpenEVSE is already doing it. Just want to know how do they do it and ...
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votes
2answers
221 views

Understanding how to power objects with a relay (featherwing, feather huzzah)

I am trying to learn how to control a relay to power various household objects. I bought a power relay shield for an adafruit feather huzzah, and I have just set up the arduino blink sketch to provide ...
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0answers
81 views

Arduino 24v I/O Shield

I'm searching an arduino uno shield that will allow to communicate with industrial grade PLC and sensors (24v). Something like https://github.com/TheDIYGuy999/Mega_PLC/tree/master/Digital_Input_Board ...
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1answer
55 views

Combining two different coding program into one sketch [closed]

Im working on project that uses a relay module,arduino atmega328 and a 2 motor 12vdc. based on coding i give, the first code is the motor 1 will run based on the input switch. and the second code the ...
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1answer
71 views

Relay Board making Output Signal Weak

I am using an Arduino Uno and Relay Shield (http://www.seeedstudio.com/blog/2013/02/28/shield-evolution-flexible-add-ons-for-arduino/relay-shield/), and using a code similar to the Teapot Demo, in ...
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1answer
105 views

Arduino Wall Wart and Relay Board Power Supply

I am relatively new to Arduino, and have been doing a project to trigger an LED/alarm when movement is detected to be over a certain threshold value. I am using an Arduino Uno, an LED/buzzer (https://...
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1answer
21 views

Using a channel relay

im using 4 channel relay to switch the motor pump. but when the arduino output is high and i check first with led. the led behavior were high too but when i attached to the relay input IN1, the ...