Incubator - INQ

In this project we will build an affordable incubator which is able to create an internal area with constant temperature and humidity. With an accuracy of +/- 0,2°C and +/- 4% relative humidity, you should be able to incubate all kinds of eggs or culture mediums regardless of the outer room temperature.

Step 1: You Will Need

Electronics:

1. Arduino Pro Mini 5V/16MHz
2. DHT22
3. 10k Potentiometer (or Rotary Encoder)
4. MicroUSB Breakout
5. NPN Transistor
6. I²C Liquid Crystal Display (16x2)
7. Relay Board
8. 5V Mini Fan
9. Power Strip
10. Halogen Lamp (approx. 60W)
11. Lamp Thread

Materials:

1. Perfboard (4x6cm, 2.54mm)
2. Pin Headers
3. Wires
4. Acrylic Panel
5. Styrodur
6. Wood (dimensions step 2)
7. Bolts [x4]
8. Hinges [x2]
9. Wood Screws
10. Wood Glue
11. Silicone
12. Solder

Tools:

1. Soldering Iron
2. FTDI Programmer
3. Crimping Tool + Terminals
4. Circular and/or Jigsaw
5. Dremel
6. Screwdriver

*To provide a sufficient insulation, we're using styrodur with a thickness of at least 0,8mm, if you don't need that much of accuracy you can also use ordinary styrofoam. For even more insulation you can use any foam as sealing for the acrylic panel.

Step 2: Preparing the Parts

To make the process of assembling easier, we prepare the parts beforehand. To do so, you just have to cut the parts, according to the sketches shown above. If you choose to use different dimensions (>65000cm³) or different material, you may need to use a halogen lamp with another wattage rating.

Step 3: Assembling the Box

If all parts are ready, you can begin assembling them, by screwing them down on the prearranged holes. Additionally, you can attach rails inside of the incubator, to make the placement of grids or plates easier.

The Control Panel gets mounted on top of the main box, to hide the powerstrip, cables and regulator and to provide an easy usage of the incubator.

If you decided to use additional insulation, like styrodur, cut it to matching size and carve lines on the backside to lay the temperature sensor and fan cables through.

Step 4: Building the Regulator

The regulator consists of basic components and is built to be as modular as possible, to make eventual replacement of parts easier. It is based around an Arduino Pro Mini, which is a cheap and easy to use microcontroller.

The schematic shown above, shows how to connect everything properly.

Step 5: Installing the Electronics

The final step of building, is installing the electronics parts and connecting them to the intended pins on the previous built regulator.

The DHT can be placed anywhere in the box, depending on your preferred use case. To find a suitable place, take a look at the data shown in step 7.

The I²C LCD displays the current temperature and humidity data and to adjust the desired values. To secure it and give it a good look, fix it by applying silicone on the edges.

The Potentiometer is used to adjust the desired values, in a predefined range, exactly. It is secured using the supplied nut.

The 5V Fan gets attached to the prepared hole in the backplates corner, to grant stable humidity. The wires can be hidden behind the styrodur plate.

The Relay acts as electrical switch to control the halogen lamp. To install it properly, you need to use the following screw terminals to interrupt the circuit [COM, NC - normally closed].

Step 6: The Code

The Code is pretty basic and if you built everything accordingly, it does not require any changes. You just need to define the values listed below to the ones that suit your use case.

1) Desired Humidity (line 17) + Tolerance (line 18)

2) Measuring Interval (line 20)

3) Ventilation Interval (line 22) + Duration (line 23)

4) Potentiometer Adjustment Range (line 25)

Step 7: Testing and Stats

The schematics shown above include some data which was collected during some incubation processes we did. This can help you to determine the perfect placement spot for your project. There will be a follow up article on how to incubate conventional chicken eggs.

Hopefully you liked this project, if you have any improvements or questions feel free to ask.