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.

Filter by
Sorted by
Tagged with
0
votes
2answers
51 views

control 3 relays with 1 button

Is there a way to control 3 relays with 1 button? My idea is: There are 3 modes; mode 1 for relay 1, mode 2 for relay 2 and mode 3 for relay 3. With a long press you switch between modes (After 3 ...
-2
votes
0answers
52 views

Why the relay isn't working?

#include <dht.h> #define dht_apin A2 // Analog Pin sensor is connected to #define CW 5 //CW is defined as pin #7// #define CCW 6 //CCW is defined as pin #8// dht DHT; const int sensorMin = ...
1
vote
1answer
39 views

Connect 5v 30a relay with Arduino Uno

I have previously connected 5V 10A relay switches to my Arduino. But for my new project I need to use a 5V 30A relay switch with my Arduino. In 10A relay switches, we make connection with Arduino ...
0
votes
4answers
73 views

Detect if laptop is on or not?

How would I safely connect an Arduino so that it can detect if a laptop is on or off? The Arduino would be powered separately by a normal USB charger, since it needs to be turned on even when the ...
0
votes
1answer
30 views

Adding WiFi to my Arduino Keypad Lock

I'm a really passionate beginner with arduino and electronics and I've built a Keypad lock for my room's door (inside the house). I've used an arduino that activates a motor using a transistor to ...
0
votes
1answer
48 views

Timer Countdown to control relay (multiple functions in void loop)

I'm trying to build this project with a simple code. Object is to hit up button to increment minutes or down to decrement minutes then hit start to start countdown, while its counting relay will turn ...
0
votes
1answer
50 views

How to code 4 relays to go off in intervals and not in sequence? [closed]

Code : //FOR AEROPONIC SYSTEM WITH ROOM TEMPERATURE AND HUMIDITY SENSOR //AND 4 GROW CHAMBERS WITH DIFFERENT SPRAYING TIME // RELAY CONTROL #define RELAY1_PIN 2 #define RELAY2_PIN 3 #define ...
0
votes
1answer
40 views

NodeMCU keeps disconnecting

I have made a home automation system consisting of a NodeMCU, 4 channel relay board running on Blynk and IFTTT. At the moment I'm only controlling a string of fairy lights and two LED strips from it, ...
0
votes
0answers
17 views

I need to connect Arduino uno with esp-01 and relay control via Android application

I have trouble connecting to esp8266-01 through arduino uno and controlling relay via Android application or a local web server. I did a lot of research. I do not want to use esp-01 independently. ...
1
vote
1answer
51 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 ...
0
votes
1answer
68 views

Activating a Relay with Wemos D1

I have a problem similar to these questions: Wemos D1 doesnt drive Relay Wemos D1 is not triggering Relay I got this BC548B transistor from an old apparatus I scratched. The transistor saturation ...
0
votes
0answers
61 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 ...
0
votes
1answer
69 views

New to arduino, help wiring relay

I am new to arduino and need some help. I just baught light bars for my jeep and wiring harnesses with them, the harnesses come with buttons and I wanted to replace the button and have them controlled ...
0
votes
1answer
28 views

Esp and blynk app

It is possible to control one relay using Blynk app and also using an atmega? To a better understanding think at a relay that will turn on a fan when you use the blynk app. but when you don;t have the ...
-1
votes
1answer
45 views

LED array flashes once before being lit

I've built this simple Arduino controlled led-array. The Arduino sets a 5v pin on a relay to connect the high current power supply to a led array. However, just before the led array is being fully ...
0
votes
0answers
47 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 ...
0
votes
2answers
65 views

Difference between these two relays (D1 Mini Relay Shield and Single 5V Relay)

I've setup my NodeMCU v3 with this relay and I got this: When using 3V to power the relay, I can hear coil when I turn on the board and I can only turn it on once. Then I can no longer hear the coil, ...
-1
votes
1answer
62 views

How to make a circuit to control a 24V solenoid

I'm new to programming with Arduino and a little rusty with circuitry. I'm trying to control a 24V solenoid with the Arduino mega board. I've done some research into this and I believe I have a code ...
1
vote
5answers
203 views

Fan regulator control from Arduino

I'm trying to control my ~230 V fan from the Arduino. Can anyone say the best possible ways to design a fan regulator that can be controlled by the Arduino using a low cost design.
0
votes
2answers
54 views

Why is my relay not triggering?

I have a 4 channel relay for my Arduino. Here's an image: From what I can tell, it's rated for 5V direct current because of the big 05VDC at the bottom, but please tell me if I'm wrong? If I'm wrong, ...
0
votes
2answers
42 views

Can the 'Adafruit Non-Latching Mini Relay FeatherWing' be used with an Arduino microcontroller such as an Arduino Mega 2560?

Can this relay found here: https://www.adafruit.com/product/2895 Be used with an Arduino Mega? The description given seems to specify that you should hook it up to their dedicated 'Featherwing Board'...
0
votes
2answers
65 views

Arduino and Solenoid Water Valve

I use Arduino UNO and two SPST Relay (Wemos Mini D1 Relay) to make the reverse polarity circuit. I use this circuit to open and close the Solenoid Water Valve (SWV), which work with 9 to 12 volt. The ...
0
votes
2answers
165 views

Esp8266 Vin pin

I've read that Vin pin is directly connected to usb cable in esp8266 (which is 5V). I wonder if I can power a relay 5V and a servo motor Sg90 with this pin? And is there any danger of doing that ?
-1
votes
1answer
50 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?
0
votes
1answer
32 views

Too little current to trigger a relay?

I try to use this relay with a Arduino Mega. I connected with jumper cables 5V pin to DC+, GND to DC- and Digital Pin 13 (because its a lucky number) to IN. The power LED from the relay is lighting ...
0
votes
1answer
159 views

Normally-Open opto-coupler board

I'm looking for a Normally-Open optocoupler board for arduino. I need to control power of a device (DC 12v, 500mA). I tried to use TLP281 board, which works, except that it inverts the output: device ...
0
votes
0answers
38 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 <...
-1
votes
1answer
54 views

12 V relay using Arduino [closed]

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....
0
votes
0answers
21 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 ...
1
vote
3answers
189 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 ...
0
votes
0answers
33 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. ...
0
votes
1answer
56 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 ...
-1
votes
2answers
97 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 ...
0
votes
1answer
72 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 ...
1
vote
1answer
44 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 ...
0
votes
1answer
60 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 ...
0
votes
1answer
187 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 ...
1
vote
2answers
214 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 ...
0
votes
0answers
55 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 ...
0
votes
1answer
26 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 ...
0
votes
0answers
238 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 ...
2
votes
1answer
79 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....
0
votes
1answer
250 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
votes
1answer
94 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 ...
-1
votes
1answer
130 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 ...
0
votes
2answers
113 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 ...
0
votes
1answer
769 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. ...
1
vote
1answer
173 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 ...
0
votes
1answer
307 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/...
0
votes
2answers
74 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 ...