Introduction: Temperature Controller for Your Greenhouse.

Hi guys

if you decide to grow plants in a greenhouse you will soon find that plants need a suitable climate. For example enough light, suitable temperature and humidity, soil nutrients and so one.

In this instructable I decided to make a cheap temperature/ humidity control system. It is suitable for greenhouse or grow tent to control ventilators, heating, humidification.

Step 1: Preface

I needed a system that measures the temperature and humidity in the greenhouse and starts some equipment at some point. If there is too much heat in the greenhouse, you need to lower the temperature ( or flood if it is cold ).

Yes, you can buy a professional, full-featured controller, but I decided to build my own controller.

It's very simple because there's a lot of control modules on the market. Basically, it's enough to connect a few wires and it is done.

I bought Digital Temperature Humidity Controller SHT2000 on AliExpress. There are models for both 12V and 220V. These model has two 10A relay, but you can buy for 16A too.

Step 2: Components

You can attach specific components directly to the controller, but it is preferable to use an power strip. For this case, I needed:

  • 1x Temperature humidity controller
  • 2x Power strip
  • 1x Power plug.
  • Wires
  • 4x Wire holders
  • 2x Wire terminal block
  • Box

I soldered the ends of all the wires.

Step 3: Wiring

Wiring is simple. A relay works as a switch. A phase conductor should be connected to the relay. The wire holders protect the wires from rip out.

The sensor is connected to the controller with a 1 meter cable. This is a short length. There is no problem to solder a longer wire. I used a 4 meter long unshielded twisted pair (UTP) cable for that.

Step 4: Box

I created box on my CNC machine, but it is not problem to buy a ready-made box (for example on Etsy) or use a Ponoko service.

Working with CNC is a great pleasure for me. I engraved a tree on the lid. I painted the ornament with acrylic paint and then sanded it with sandpaper. There are a lot of suitable vector graphics on

Have a good time.