Cooling down your Aquarium by using a temperature controlled Fan

Please put some money in the tip jar by clicking on the donate button to support me so I can continue creating contend like this. P.S. please donate more than $1 as PayPal takes minimum $0.30 per transaction

Every aquarium lover is afraid of hot weather. It often means that your tanks are going to be overheating. This can lead to catastrophic results.  An easy fix for smaller tanks is to place a small USB fan on top of your tank. It can drop the temperature of your tank by almost 3C  less than the the ambient room temperature.

The drawback is that you have a lot of water that evaporates, and  your tank temperature can get too cold if your ambient temperature in your room drops. This is why I created an electronic switch using an Arduino that turns the USB fan on or off depending on the temperature of the water.

I created a list of what you need and where to get it. I also created a diagram how to put it together, and even wrote the sketch that operates this all. 

What you need:

QTY

Description

Cost

Total

Supplier

SKU

1

ENCLOSURE, PLASTIC BOX LX 422 101X40X52MM

2.99

2.99

Lee's Electronics

10361

1

Printed Circuit Board

1.7

1.7

Lee's Electronics

10496

1

Arduino Pro Mini

23

23

Lee's Electronics

11008

1

USB Charing Cable 1 M

6

6

Amazon

1

DS18b20 waterproof Temperature Sensor

13.25

13.25

Lee's Electronics

1255

1

STANDOFF PLASTIC F/M M3X12MM 10PCS

2.8

2.8

Lee's Electronics

 62650

1

SCREW NYLON PLASTIC M3 6MM 10PCS

2.5

2.5

Lee's Electronics

61569

1

transistor 2n2222 5pcs

1

1

Lee's Electronics

7174

1

Misselanious wire/others/Resistors 1K/4.7K

5

5

Lee's Electronics

1

ChillOut® 6" Manual Control USB & AC Adapter Desk Fan, Black

19.99

19.99

Staples

580700

Lee’s Electronics web site is: http://leeselectronic.com

How To Connect the components

Connecting the DS18B20 water Proof Temperature Sensor

Sensor

To:

Notes

Red Wire (Vin)

5V

Can be different colour

Black Wire (GND)

GND

Can be a different colour

Data Wire (White)

D2 on Arduino/Pullup 4.7K resistor to 5V

Can Be a different colour

Connecting the Fan to NPN 2N2222 resistor.

USB Fan

TO

Notes

Connect red Wire

5V

 

Black Wire

Collector NPN transistor

 

Connecting NPN 2N2222 resistor Flat side facing you.

NPN Resistor

TO

Notes

Collector Pin 3

GND Fan (Black Wire)

 

Base Pin 2

1K Resistor Connected to Pin 10

 

Emitter Pin 1

GND

 

Quick build overview

Start with cutting of the USB part of your Fan purchased at Staples. As Stated connect the red wire to 5V and the black to the collector pin of your transistor. If you use a different Fan make sure you know what colour wires you need to connect, otherwise you have a good chance it will run backwards or not at all.

If you have an unused USB charger cable laying around you can cut the mini plug off the end. Check with a multi meter what wire is power and which is ground. Connect power to the raw pin of your Arduino Pro Mini and the gnd to the gnd of the Pro mini.

Before you solder Steps

Completed PCB in the enclosure

Use the PCB  as a guide to drill holes in your enclosure for the standoffs. Screw the standoffs in the holes and use a knife to trim of the excess from the back. Drill a whole big enough to put all the cables through in the side of the enclosure.

Build Diagram

Pull the wires through the whole you just drilled before you start soldering. Follow the Build diagram how to connect everything and solder it on the PCB.

 

 

Arduino Sketch

The Arduino Sketch you can download from here. In the top of the sketch there is a variable called maxtemp. This indicates the maximum temperature you want your aquarium to get before the fan is turned on. You also going to need the following libraries: