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Topic: Help Required on Auto Water for Plants (Read 1 time) previous topic - next topic


Jan 24, 2013, 06:54 am Last Edit: Jan 24, 2013, 06:58 am by vijaybhatter Reason: 1
Hi Friends,

I have a 3.5V~12V Immersible Water Pump and as per its specifications it works at 60mA to 500mA and a Moisture Sensor for the plants. Both I have purchased from DFRobot.

The Immersible pump product I am talking about is : http://www.dfrobot.com/index.php?route=product/product&product_id=667

The problem I am facing is with powering the pump using the Arduino UNO with any of the digital pins. When I connect it directly to 5V pin it works fine. So I assume its not getting the required power to start the pump.

My Sketch looks as

Code: [Select]

int sensorPin = A0;  
int sensorValue = 0;  
int pumpPin = 2;
int ledPin = 13;

void setup() {

void loop() {
 // read the value from the sensor:
 sensorValue = analogRead(sensorPin);    
 if (sensorValue >= 500){
   //Start the Pump and the LED

Everything works fine except powering the pump through the DigitalPins. Any suggestions on how to solve this.




You should not power the pump directly from the Arduino pins. To much current, it can damage the Arduino.

Buy a relay module:

You connect the digital output directly to the module and the pump to the relay side of the module.

Alternative you can build it yourself. It is just a transistor and a relay with a freewheel diode.


I have a 3.5V~12V Immersible Water Pump and as per its specifications it works at 60mA to 500mA

Even the lower figure is well above the absolute maximum rating for an AVR pin, which is 40mA.
If you tried to run the pump for any length of time, you may well have damaged your processor.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.
I speak for myself, not Arduino.


Hey Vijay, did you solve your problem?
I am having the same problem with the same water pump. I'm using a relay and for some reason the pump works only sometimes. The pump works fine when I connect it directly to the power source. When in the circuit only sometimes. I checked with a multimeter and when the pump is connected the current goes high and then it drops to zero like in a second. If I connect a normal motor instead the circuit works perfect.

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