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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62 views

Eleminate noise from a Relay in ArduinoFFT

I have built a circuit with an Arduino Nano to measure frequency from my music, it's basically this schema but I changed the code a little bit to fit my needs. My problem is I want to add a Relay (I ...
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542 views

Connect 5V relay to ESP32 WROVER B board

I need to use a ESP32 WROVER B based MCU board with a standard (cheap) one-channel 5V relay (e.g. to switch on a mains-power appliance). Attempted removal of excess solder around the headers ...
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2answers
160 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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95 views

ESP8266 WiFi Module disconnects from WiFi itself

#define id "qwerty" #define password"123456789" int relayPin= 4; void setup() { Serial.begin(115200); Serial.println("AT"); pinMode(13, OUTPUT); pinMode(relayPin, OUTPUT); delay(3000); ...
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131 views

Simple relay switching program crashes UNO

A very simple digitalwrite(pin, HIGH) delay(1200) digitalwrite(pin, LOW) delay(1200) crashes the uno after about half an hour. Of course it works again after pressing the reset button. It's ...
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233 views

Opening and closing a hatch with different switches

I'm new to the whole Arduino thing and I'm not much of a programmer myself so I need some help... The goal is to have 4 buttons which a person who operates it gives out different outputs from the ...
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51 views

Arduino connection confirmation

I am using Arduino Uno. I want to control my room lamp both manually and over the network, so when I switch off my lamp manually, how do I get acknowledgement over the network that lamp is off ?
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73 views

How to splice into existing buttons?

I want to control a kettle. It has 4 buttons and a digital disply of the temp. I would like the buttons and disply to remain functional. I just want to make the buttons remoteky pressabke. The buttons ...
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257 views

Using Arduino BLE Nano to switch an electric circuit on and off

I'd like to use an Arduino Nano BLE to activate or deactivate an electric circuit. I intend to use a relay to do so, but activating a relay seems to require a current with more intensity than what we ...
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290 views

DFRobot Bluno + Relay Shield

I'm a new to all things electronics and I'm having trouble using a DFRobot Bluno V2 with a DFRobot Relay Shield for Arduino V2.1. For testing purposes I've done the exact same circuit as represented ...
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2answers
89 views

Digital pin output voltage fall down when driving a relay

I'm trying to trigger 8 different 5V relays using arduino atmega 2560. the relays (70Ohm coil) are powered by an external 5V source, and im trying to trigger them through a driving stage which ...
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39 views

USB and LM7805 both to power Arduino

I have high current usage For my circuit as you can see below (link): I like to power Arduino when it is not connected to PC by USB Connection, So I want to add one external power supply and connect ...
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64 views

HC-05 bluetooth module short range

I have started learning about arduino and just bought a bluetooth module, HC-05. From where i bought, it says it has range of approx.10 meters. I made hc-05 connection with arduino in below described ...
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130 views

I'm desperate and need help with MFRC522 (stops working randomly)

I've made a light switcher that switches lights on for 15s after a correct tag is presented, and also when door is opened for 6 seconds (its for outside) so i can see a keyhole after leaving for a ...
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41 views

Peculiar relay behavior from POST

I am trying to toggle on/off between two separate HTTP request. One submit button to turn it on, and another separate submit button to turn it off. I expect the device to launch in the off/low 0V ...
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1answer
90 views

Connecting a time on/off circuit and my adafruit neopixel light strip

I'm new to programming and hardware so be gentle. I've used this tutorial https://www.instructables.com/id/Arduino-Ultra-Mega-Timers/ to create a time on/off circuit. I'm attempting to connect some ...
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Noob here.. Need help with a thermostat controlled relay

So After trying several sketches for a LM35 and none working I finally found one that was giving me accurate results. The problem is the code is way over my head. I was able to modify it enough to get ...
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42 views

Use esp-01 relay with Nodemcu possible?

I'm building a simple mobile controlled relay switch. however, I'm out of relay modules, but I do have these esp-01 relays: https://ae01.alicdn.com/kf/HTB1VIKLeJLO8KJjSZFxq6yGEVXaW.jpg I'm wondering ...
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71 views

Arduino code does not function when relays are powered

I have a mega arduino, which is supposed to to power 4 relays using 4 touch sensors TTP 223, the relays are 5V coil and 220V. the arduino is powered by a 5 V adapter "mobile phone charger" and it ...
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134 views

Made a light controller for the holidays

I am a new the world of Arduino. I found on YouTube, how to build a light controller (https://www.youtube.com/watch?v=WvG9c84ApFA&t=39s). I follow every step but it doesn't work. Here are some ...
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1answer
263 views

The current direction for digital output pins

I am new to Arduino. The digital pins can be configured as output (https://www.arduino.cc/en/Tutorial/DigitalPins) for triggering some sensors. I am now setting a digital (output pin), say no. 7,which ...
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261 views

Can I use the NodeMCU ESP12 5v pin and control it with a relay?

This question might be a little esoteric, but I cannot find any answer for it. Situation: I want to have more than 8 Analog sensors on a NodeMCU ESP32. Unfortunately due to SPECTACULARLY poor design ...
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576 views

Wemos D1 is not triggering Relay

Update: I realized my relay module was 12V and the current leaving the digitalpin from my Wemos D1R1 is only 3.3V. I bought a 5V relay module that I read in some articles that it could work, but it ...
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88 views

Rfid stops scanning after wrong card scanned

My Rfid reader stops scanning cards after scanning the wrong rfid card. It doesn't scan it anymore after turning off the relay. *It turns on the relay if my rfid card is the right one #include <...
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24 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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434 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
552 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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255 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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347 views

Trying to use NodeMCU ESP-12e, a 5v relay AND a solenoid lock on same 12v power wall-wart

Noob here, so be gentle. Using a 12v-5/3.3v power board, NodeMCU powers relay fine, 100% of the time. Add in the solenoid by soldering a line from the wall wart into the COM spot on the relay, and ...
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71 views

Wiring a RT314F12 latch relay to an Arduino

I want to automate the lights in my house. To do this, I want to use a latching relay, so it will only use current when switching. I found a quite cheap latching relay RT314F12 but I do not know how ...
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1answer
2k views

Relay for controlling a water pump motor

I want to switch on and off a motor with arduino, used for pumping water. I need to have a idea which relay could be used with arduino. Here is a photo of a similar motor:
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65 views

XH-M131 Photoresistor Relay Module NC position

I have purchased XH-M131 Photoresistor Relay Module to automatically light my outdoor yard at sunset and turn it off at sunrise. I'ts working as it is supposed to, However, if I power off the relay, ...
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1answer
122 views

Optimal and Save Water Pump Control

I'm using an Arduino Micro, a 12 V water pump and a print relay to water a plant. A water level switch monitors the the water tank to make sure the water pump does not run dry. I tried different ...
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1answer
1k views

Powering 8-channel relay correctly

Replication Steps: 595N shift register powered by arduino Each output on register connected to 1 of 8 relays in relay board Arduino programmed to loop over each 8, triggering 1 relay at a time ...
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1answer
412 views

L293D with arduino's 5V

I am trying to use L293D with relay to power a 12V DC motor. Can I use arduino's 5V to provide L293D inputs 4 and 8 such as in the drawing? Or do I need to use a separate source, e.g. a power module?
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365 views

Which relay should I use to control the power from mains?

I was making a home automation project in which I want to control appliances like a fan and a bulb through voice commands with the help of an arduino uno and a relay but I am confused which relay to ...
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1answer
206 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 ...