SENSORS/ACTUATORS

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Arduino MKR WiFi 1010 - Control Pump

Learn to control 12V water pumps with your Arduino MKR WiFi 1010! Master relay-based pump switching to build automated watering systems, aquarium controllers, cocktail makers, and fluid management projects. This fundamental tutorial teaches safe high-power pump control—essential for any liquid-handling automation.

Two parts can sit between the MKR board and the pump: a relay or a MOSFET module. With the relay, the pump is either running or stopped. With the MOSFET module, the pump can also run slowly for a gentle flow or fast for a strong flow, and it switches without any click. This tutorial teaches you both.

What You'll Learn:

Safe relay-based control of 12V submersible pumps
Pump control with a MOSFET module, including flow (pump speed) control by PWM
Proper power distribution for pump circuits
Programming timed pump activation cycles
Foundation for sensor-triggered pumping systems

Real-World Applications:

Automatic plant watering: Moisture sensor triggers pump for irrigation
Aquarium systems: Timed water changes, filter circulation
Cocktail/beverage makers: Precise liquid dispensing
Coffee machines: Automated brewing cycles
Hydroponics: Nutrient solution circulation
Lab automation: Chemical reagent dosing
Water features: Fountain control, waterfall pumps
Cooling systems: Liquid cooling loop management

Safety Note: Always use submersible pumps rated for your liquid (water pumps for water only!). Never run pumps dry—they require liquid for cooling and lubrication.

Tutorial Scope: This guide covers basic ON/OFF timing. For advanced sensor-triggered pumping (moisture-based watering, level-controlled filling), see our project tutorials listed at the end.

Hardware Preparation

1	×	Arduino MKR WiFi 1010
1	×	Micro USB Cable
1	×	Relay
1	×	Alternatively, MOSFET Module (AOD4184, LR7843 or FR120N)
1	×	12V Pump
1	×	Vinyl Tube
1	×	12V Power Adapter
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack

Or you can buy the following kits:

DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of 12V Submersible Pumps

12V DC submersible pumps are compact, low-voltage water pumps designed for Arduino projects. Understanding their specifications ensures reliable operation and proper power system design.

Pump Pinout and Specifications

image source: diyables.io

Electrical Connections:

Red wire (+) - Positive terminal:

Connects to +12V of DC power supply
Polarity-sensitive—reversing damages internal electronics!

Black wire (-) - Negative terminal:

Connects to GND (ground) of DC power supply
Completes circuit for motor operation

Key Specifications (check your pump's label/datasheet):

Voltage: Typically 12V DC (operating range: 9-13.5V)
Current draw: 0.5-2A depending on pump size and load
Flow rate: 2-6 liters/minute (L/min) or 120-360 L/hour
Max head height: 1-3 meters (vertical pumping capability)
Power consumption: 6-24W typical
Duty cycle: Some pumps require rest periods (check specs!)

Important Notes:

Submersible design: Must be submerged in liquid for cooling—running dry damages seals and motor
Water only: Use water-rated pumps for water; chemical pumps for other liquids
Inlet filter: Keep inlet screen clean to maintain flow rate and prevent clogging
Priming: Some pumps need priming (filling tubing before operation) to start pumping

How to Control Pump with Arduino MKR WiFi 1010

Direct Power Operation: Connect 12V power supply directly to pump → Pump runs continuously at full speed.

Arduino-Controlled Operation: We need a relay as an electronic switch.

Why Relay Control is Necessary:

Voltage incompatibility: Pump requires 12V; Arduino pins output only 3.3V
Current demand: Pumps draw 0.5-2A; Arduino pins supply maximum 15mA
Electrical isolation: Keeps high-power pump circuit separate from Arduino logic

Direct connection would:

Fail to start the pump (insufficient voltage)
Overload and destroy the Arduino pin (excessive current)
Risk damaging the entire Arduino board

The Relay Solution:

The relay acts as an electrically-isolated switch controlled by low-power Arduino signals:

Arduino sends LOW signal → Relay coil deactivated → Relay contacts open → Pump OFF (no 12V connection)
Arduino sends HIGH signal → Relay coil activated → Relay contacts close → Pump ON (12V applied to pump)

Control Circuit:

Low-power side: Arduino pin → Relay coil (3.3V, ~50mA)
High-power side: 12V supply → Relay switch → Pump (12V, 0.5-2A)

Relay Selection: Choose relay rated for at least:

Coil voltage: 5V or 12V compatible with your Arduino setup
Contact rating: Minimum 10A @ 12V DC (safety margin above pump current)
Example: SRD-05VDC-SL-C relay (10A contact rating) works perfectly

Not Familiar with Relays? Our Arduino MKR WiFi 1010 - Relay tutorial provides comprehensive coverage:

Relay pinout and electromagnetic operation principles
How coils control switch contacts
Wiring diagrams for NO (Normally Open) and NC (Normally Closed) configurations
Programming relay control with digitalWrite()
Selecting appropriate relay ratings
Troubleshooting common relay issues

Master those concepts first, then return here to apply them to pump control!

Going with a MOSFET module? First see the Arduino MKR WiFi 1010 - MOSFET Module tutorial. It explains the module's screw terminals, the PWM pin and the three chip versions.

Which One for Your Pump: Relay or MOSFET Module?

	Relay	MOSFET Module
What you can do	start or stop the pump	start, stop, and change the flow (pump speed) with PWM
Sound when switching	a click	none
Speed of switching	slow (some milliseconds)	very fast
Lifetime	contacts get worn over time	no moving parts inside
Pump type	AC or DC pumps	DC pumps only
Pump supply	any, within the relay rating	at least about 6V (needed by the gate)
Isolation from the MKR	yes, coil and contacts are apart	yes, through a PC817 optocoupler
Pick it for	AC pumps or plain ON/OFF	12V DC pumps, flow control, frequent switching

For a 12V DC pump, the MOSFET module is a nice upgrade. A plant waterer can give a slow flow so water does not splash, and a fountain can change its height. If your pump runs on AC, the relay is the only choice of the two.

Wiring Diagram between Arduino MKR WiFi 1010, Relay and Pump

The wiring diagram between Arduino MKR WiFi 1010 Pump

This image is created using Fritzing. Click to enlarge image

Arduino MKR WiFi 1010 - Pump Code

The code below turns the pump on and off every 4 seconds.

Detailed Instructions

New to Arduino MKR WiFi 1010? Complete our Getting Started with Arduino MKR WiFi 1010 tutorial first to set up your development environment.

Connect the components to the Arduino MKR WiFi 1010 board as depicted in the diagram
Plug your Arduino MKR WiFi 1010 into your computer's USB port
Launch the Arduino IDE on your computer
Select the Arduino MKR WiFi 1010 board and its COM port
Copy the above code and paste it into the Arduino IDE.
Compile and upload the code to the Arduino MKR WiFi 1010 board by clicking the Upload button in the Arduino IDE.
Check the pump’s status.

Line-by-line Code Explanation

The Arduino MKR WiFi 1010 code above explains each line. Please read the comments in the code!

How to Control Pump Flow with MOSFET Module

The relay version only turns the pump on and off. Here, the MOSFET module lets the Arduino MKR WiFi 1010 also choose the pump speed, so you get more or less water flow.

Wiring Diagram between Arduino MKR WiFi 1010, MOSFET Module and Pump

The wiring diagram between Arduino MKR WiFi 1010 pump MOSFET module

This image is created using Fritzing. Click to enlarge image

Control side: MKR pin 6 goes to PWM, and an MKR GND pin goes to GND.
Power side: the pump red wire and the 12V adapter + both go into the + terminal. The pump black wire goes into LOAD. The 12V adapter − goes into −.
Flyback diode: the pump has a motor coil, so place a 1N4007 or 1N5819 diode across the pump wires, with the stripe (cathode) on the pump + side.

Arduino MKR WiFi 1010 - Pump Flow Code

/* * This Arduino MKR WiFi 1010 code was developed by newbiely.com * * This Arduino MKR WiFi 1010 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-mkr/arduino-mkr-wifi-1010-controls-pump */ const int MOSFET_PIN = 6; // Arduino MKR WiFi 1010 pin connected to the PWM pin of the MOSFET module void setup() { Serial.begin(9600); pinMode(MOSFET_PIN, OUTPUT); analogWrite(MOSFET_PIN, 0); // start with the load OFF } void setLoad(int percent) { int duty = map(percent, 0, 100, 0, 255); // convert 0-100% to 0-255 analogWrite(MOSFET_PIN, duty); Serial.print("Load power: "); Serial.print(percent); Serial.println("%"); } void loop() { // turn the load fully ON, then fully OFF Serial.println("Load: ON"); setLoad(100); delay(2000); Serial.println("Load: OFF"); setLoad(0); delay(2000); // increase the power step by step (PWM) for (int percent = 10; percent <= 100; percent += 10) { setLoad(percent); delay(500); } // decrease the power step by step (PWM) for (int percent = 90; percent >= 0; percent -= 10) { setLoad(percent); delay(500); } delay(1000); }

First the pump runs at full flow for 2 seconds, then it stops for 2 seconds. Next the power rises from 10% to 100%, so the water flow gets stronger, and then it falls back, so the flow gets weaker. At low power, a pump may only hum and not push water.

Detailed Instructions

Use the same IDE and board setup as in the relay Quick Steps above.
Put the pump in water, then wire it with the MOSFET module as in the diagram.
Upload the code above to the MKR board.
Connect the 12V power adapter.
Open the Serial Monitor with 9600 baud and watch the water flow.

Newbiely | Arduino IDE 2.3.8

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Newbiely.ino

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8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'Arduino MKR WiFi 1010' on 'COM15')

New Line

9600 baud

Load: ON Load power: 100% Load: OFF Load power: 0% Load power: 10% Load power: 20% Load power: 30% Load power: 40% Load power: 50% Load power: 60% Load power: 70% Load power: 80% Load power: 90% Load power: 100% Load power: 90% Load power: 80% Load power: 70% Load power: 60% Load power: 50% Load power: 40% Load power: 30% Load power: 20% Load power: 10% Load power: 0%

Ln 11, Col 1

Arduino MKR WiFi 1010 on COM15

Tip: The MOSFET module is for DC pumps with a supply of about 6V or more. Keep the relay for AC pumps.

Video Tutorial

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