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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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Problems sending data to my arduino from python using pySerial

im trying to send a '1' or a '0' to my arduino in python using pySerial so from my arduino i can read whatever the python program sends and then turning a relay on and off depending on what it reads ...
user98268's user avatar
-2 votes
1 answer
92 views

Is it possible to power an Arduino and a bulb from the same source without a risk [closed]

Can I power the arduino and a bulb from the same power souce while controlling the bulb by a relay driven by arduino? the bulb is using 6W, if important. Did I connect the ground wire and the positive ...
playmobox's user avatar
2 votes
1 answer
59 views

Communication between 3.3 V and 5 V system

I am using an ESP8266-01S that only works with 3.3 V power. I want to control a 5 V relay. I gave each component its own power source and got an NPN transistor and wired it like in the diagram, but ...
Samy ashraf's user avatar
-1 votes
0 answers
47 views

ESP8266 NodeMCU ESP relay control problem

I'm running into a problem trying to control a relay with ESP8266. The relay works I can manually apply power and hear it click when it turns on/off. I'm taking one of the digital outputs to control ...
Jason Crosby's user avatar
1 vote
1 answer
63 views

NodeMCU 1.0 - Port D3, relay and pump does not boot

I'm trying to create a watering system using a NodeMCU 1.0, a relay and some pumps. Currently I've port D0, D1, D2, D5, D6, D7, D8 already in use. I'm trying to use the port D3 (GPIO0) as follows, but ...
Timmy's user avatar
  • 195
2 votes
2 answers
86 views

Grove relay stuttering

I have bought this Grove relay: Grove - Relais | Kiwi Electronics. I use it to drive a low-power water pump with a 9v battery. So the pump circuit is isolated from the Arduino circuit. When the ...
mvermand's user avatar
  • 407
0 votes
1 answer
56 views

Can Vin of ESP handle many voltage sensors and relays?

My project is Charging Battery via Solar and Piezoelectric sensor while also getting the Realtime Voltage of the Battery, Capacitor, and Solar. I want to use Vin as the source to get 5V because ...
walter's user avatar
  • 1
1 vote
1 answer
121 views

Water pump relay switching too fast

I'm using a water level sensor with two outputs, a 5V fan and a water pump. Here's the wiring . What I want to do with this project is: When the water reaches 2 cm, then the water pump is on while ...
jeonsann's user avatar
0 votes
1 answer
92 views

How can I switch the power on/off to cut BIG currents (200A)? [closed]

Context: I have an off-grid cabin with PV powered 12V DC. I want to cut power to an inverter (12V DC ->220V AC) when I leave by pressing a button as it draws too much in standby. Most relays I have ...
oligofren's user avatar
  • 111
0 votes
1 answer
529 views

ESP32 struggling to trigger relay module consistently

I'm working with a 4-channel, 5 V relay module and an ESP32 which operates on 3.3 V. The setup seemed to work well initially but I have started experiencing some inconsistencies. One of the four ...
Hach Rbh's user avatar
2 votes
0 answers
75 views

Arduino code intermittent

Have an alarm for "tea time", "lunch time" and "tea time". Works well at times but occasionally it gets stuck on the alarm not resetting, other times it does not trigger ...
Nic Kemp's user avatar
2 votes
0 answers
63 views

Pump running even if relay says "off"

I have a relay that should be switched off when the analog value is too high by the Arduino code: int digitalPin = 4; // for the relay int analogPin = A0; // for the soil moisture sensor int ...
Revolucion for Monica's user avatar
1 vote
0 answers
60 views

Selecting the Right GPIOs

I've bought this 4 relay ESP8266 board to active lights and window shades. In an odd way - its relays are not pre-connected to a certain IO's but let you choose which IOs will operate relays (by ...
guyd's user avatar
  • 1,049
2 votes
2 answers
52 views

change sketch from controlling 8 stepper motors to 8 solenoids

I am looking to see if I can change the attached sketch which controls 8 stepper motors to just switching 8 relays for a weaving loom which we have, unfortunately making this change is well above my ...
Vaughan Ratahi's user avatar
1 vote
1 answer
234 views

esp based smart light system over alexa malfunctioning

i made a home automation system using esp 32 and 8 channel relay but within 2 or 3 months my relay automatically turns off after sending the signal to it through esp32 but if i connect directly ...
Rathore Brothers's user avatar
1 vote
0 answers
46 views

Connecting HM-10 and relay to Arduino Uno

I have an 8 channel relay, an Arduino Uno, and this HM-10 bluetooth module: https://www.amazon.com/dp/B06WGZB2N4 The Goal Send a number (1-8) from my Android phone via bluetooth to turn a relay on. ...
badhorsebadhorse's user avatar
1 vote
0 answers
84 views

Pushbutton firing somewhat randomly

I have a circuit which consists of a pushbutton and 2 relays. The power supply is driven either over USB, where the circuit seems to work fine, or powered by a linear regulator board I've knocked ...
XtrmJosh's user avatar
  • 119
0 votes
1 answer
162 views

Using Millis instead of delay to reboot relay

I want to reboot relay (turn off , waiting 4 seconds and turn ON) it works perfectly if I use delay(4000), but code is blocked while delay (4 seconds) and I cant start relay 2. How can I use Millis ...
vito's user avatar
  • 101
-1 votes
2 answers
421 views

How to connect a 4 channel relay switch directly to a 5V power source?

When connecting a 4 channel relay to a Arduino Pro mini, there is a noticeable power drain from the board when relays are active. This is clearly visible as the 16x2 LCD dims. I remember reading that ...
Yanick Rochon's user avatar
3 votes
3 answers
129 views

How to perform multitask using arduino such as update data as well as check condition?

Here data is updated after every 2 seconds. But when the condition is true then the valve and motor process starts and data is updated only after completion of that part (i.e., data is updated after ...
Jashanjot Kaur's user avatar
2 votes
0 answers
36 views

Can the Blink class be used on a 5v to 240v relay?

I have found the following code and it works fine on a breadboard controlling small LEDs but I want it to work with LED strip lighting with external 240v transformers. We have built the circuit using ...
Zed's user avatar
  • 21
1 vote
0 answers
62 views

Relay switch problem: Arduino Nano with a 312 PIR sensor

I am working with a 312 PIR sensor with an Arduino Uno Nano. When sensing motion Port 13 goes High for Time_A (10 minutes). If I then press a push button on the Arduino board it takes Port D2 LOW, ...
sean's user avatar
  • 11
-1 votes
1 answer
157 views

Arduino controlled 25A 12V DC relay

I have an air compressor that I often give difficult tasks, where the compressor needs to run longer than it was designed for. So it gets close to overheating, which requires periodically giving the ...
Ryan Budney's user avatar
0 votes
1 answer
478 views

NodeMCU with a 5V latching relay - LOW triggers relay

I am going to connect NodeMCU to a latching relay board like tis one (4 channel version): LINK Both MCU board and relay board will be powered from the same 5V voltage regulator. Now I have two ...
michal's user avatar
  • 103
2 votes
1 answer
405 views

Using MAX30100 SpO2 value to turn on LED

max30100 i2c sensor gives heartrate and spo2 reading in serial and also can show values in lcd display. I want to show it's indication via LED. If SpO2 value <94 , it will turn on Red led in ...
Sayzar's user avatar
  • 23
1 vote
2 answers
810 views

Back EMF from Relay causing trigger on INPUT pin

I am wiring up a light show for my pickup truck. I have installed various high power spotlights and light bars into a dedicated relay/fuse box in the engine bay. These relays are wired into a switch ...
Matt D's user avatar
  • 113
1 vote
0 answers
76 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 ...
Alex Dupuis's user avatar
1 vote
0 answers
444 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 ...
Soheil Paper's user avatar
2 votes
1 answer
123 views

Error trying to simulate temperature dynamically

I'm trying to simulate dynamic temperature using a small set of data with ESP32. I've just realized that the relay doesn't change the status if there is some variation of the temperature upper or ...
s_tatus3's user avatar
0 votes
2 answers
238 views

Arduino Uno - Raspberry PI - Float Sensors - Water pumps

I am experimenting with Aquaponics and since I am a software developer I found it "smart" to use arduino/raspberry in order to control the water flow and not simply use a water pump with ...
Investigator's user avatar
0 votes
2 answers
711 views

2 way switch with Arduino?

Hey I'm working on a home automation system where I can replace one of my 2 way switches to an Arduino Or node MCU controlled one but I want to avoid normal relays because as of what I know they can ...
rohithrathod banoth's user avatar
1 vote
0 answers
378 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 ...
usmandroid's user avatar
1 vote
1 answer
297 views

NodeMCU and relay with VIN power

Have read a lot of different things online, and I just ain't sure yet. I'm trying to hook up a NodeMCU to control some relays. And want to power the NodeMCU by the VIN pin. Anyone know if this setup ...
John's user avatar
  • 13
1 vote
1 answer
630 views

Digital pins are no longer outputting enough to click a relay

I've been working on a project for awhile now, and I ran into a problem a week ago I couldn't solve. I'm using an Arduino uno R3. My project involves the use of 4 relays triggered by the digital pins. ...
MelBel03's user avatar
3 votes
1 answer
131 views

Reproduce simulated temperature data with Arduino

I'm starting a test using Arduino to reproduce a set of temperature values in water each three hours and need some help with it. I will use two ds18b20 sensors to control two thermostats connected to ...
s_tatus3's user avatar
2 votes
1 answer
75 views

Arduino changing output based on wire voltage

I’m new to arduino and I want to build myself smart switch that can be turned of both manualy and via wifi, is there any way to change position of relay based on if another wire is live or not? Im ...
krystof18's user avatar
  • 315
1 vote
1 answer
1k views

Control DC motor in both directions with two relays

I am using an Arduino and two relays to control 12V DC motor. I need to rotate the motor in both directions. For the first trials it worked fine. Finally one next switching fried my Arduino. I think ...
zhekaus's user avatar
  • 439
2 votes
1 answer
592 views

digitalRead() function of Arduino doesn't read Input value sent by sensor after detecting the object

I'm trying to turn ON the LED(inbuilt/PIN13) when photoelectric proximity sensor(12v) senses any object. Sensor is connected on pin 2. Assigned pin 2 as INPUT, I've got a 12v spdt relay for switching. ...
Prathamesh Konkar's user avatar
1 vote
1 answer
932 views

Driving 5V relay with ESP-01

I'm trying to drive a 5V relay with 3.3V ESP-01 with schematic below. I programmed the ESP to start a portal through which I can derive the relay by triggering GPIO-0 & GPIO-2. However when I ...
ASH's user avatar
  • 45
0 votes
1 answer
112 views

How to close humidity sensor at specific humidity

I am using dht humidity and temperature sensor on arduino and i would like to add relay and buzzer on the system. What I would like to do is to close it via buzzer and on 65% humidity run buzzer. The ...
krank s's user avatar
1 vote
0 answers
555 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 ...
user14972314's user avatar
1 vote
1 answer
95 views

Help with NodeMCU based smart switch

The project I'm planning is to use a NodeMCU at each electrical board in house to control lights and fans via relays. Each MCU will communicate via MQTT over WiFi to a Raspberry Pi 4 from where I can ...
coldbreeze16's user avatar
1 vote
0 answers
26 views

error ph meter cant show the data [duplicate]

im using ph meter DFROBOT v1.0 at i compiled the code from the DFROBOT web this is the code * # This sample code is used to test the pH meter V1.0. # Editor : YouYou # Ver : 1.0 # Product: ...
daffa faiz's user avatar
1 vote
0 answers
49 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 ...
brad's user avatar
  • 201
0 votes
2 answers
184 views

Turn on relay for amount of time by continuous input

I have a project having two input status first the input is not continuous the output buzzer relay will be on for 10 seconds and then turned off or it can be off directly by push button the second ...
eng.hamza's user avatar
0 votes
2 answers
281 views

How to use a push button & transistor as a kickstarter for power supply?

My goal is to save energy, and I intend to do so by powering a chip with itself, and cut power whenever unnecessary. The best image I can have is of a startled monkey who jumps on the branch, screams ...
B7th's user avatar
  • 167
-1 votes
1 answer
2k views

Can i connect in pin of relay module to Analog pins of arduino instead of digital pin?

Im a complete beginner Im making a project using relay modules and arduino. but all the digital pins of my arduino are filled. I wanted to ask if i can use the analog pins to connect my relay module ...
rohithrathod banoth's user avatar
2 votes
1 answer
3k views

Which relay module to buy and what is the difference between 1 channel and 2 channel relay boards

I wanted to d a simple circuit using Arduino to control the lights in my house. But i do not know which relay module to use my house runs on standard 220v ac. Can anyone tell me weather this relay ...
rohithrathod banoth's user avatar
0 votes
1 answer
98 views

How to stop the relay after it is getting on and let the sensor get the result

I want to provide a delay in the following iteration reading so that the sensor can read the condition after the pump starts. void loop() { //-------------Fungsi Read sensor----------- // ...
daffa faiz's user avatar
2 votes
1 answer
101 views

Relays just switch ON and OFF on delay(), not on millis()

I use fuzzy logic for the running time of relays, but the relays just switch ON and OFF at the interval of the delay() I put at the end of loop. This is my code: void loop () { ph = -180/100.0; ...
daffa faiz's user avatar

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