Dankubator Instructions

Dankubator Instructions

This is a work in progress. I wanted to get something up asap for anyone who is confident without more details. I will refine this in the coming weeks to have more details, photos, videos, etc.

(Scroll down for photos)

Overview

The overall process is something like this:

  • Cut holes in a food grade hot box
  • Attach a thermoelectric (peltier) cooler through some of the holes
  • Attach an outtake fan on one of the holes
  • Attach a damper on the intake vent (I will probably add one to outtake soon)
  • Run wiring through one of the holes to connect to these components inside of the box
    • The cooler and cold sink fans
    • A circulation fan
    • A temp/rh sensor (sht30)
    • A temp/rh/pressure sensor (bme280)
  • Then, outside of the box
    • Connect a 12v power supply to a 5v buck converter
    • Power a raspberry pi with the 5v
    • Run the 12 and ground to components
    • Share ground between 5v and 12v circuits
    • Install the code on the pi (It is in a private GitHub repo I will make public once I figure out which account to use.)

Parts List

You can find the parts list on this post.

Tools

  • 3-inch hole saw
  • 4-inch hole saw
  • Screwdriver
  • Drill
  • M4 Screws

Step by Step

Cut holes in the container

First, the bottom of the container

  • 4-inch hole, towards the front, will be the air outtake vent
  • 3-inch hole, towards the back, will be where we run the wires in
  • Also, drill four pilot holes for mounting a 120mm fan on the 4-inch hole
Bottom of the container. The smaller hole is towards the back of the container.

Next, the back of the container

  • Two 3-inch holes in the middle
  • 4-inch hole near the top left
Back of the container.Note: The container is upside down. The 4-inch hole is the top-right. The 3-inch holes are in the middle.
Container upside down showing all cut holes on the bottom and back.

Now we can attach the components to the Dankubator

  • Attach the cooler module and the damper to the holes on the back of the box.
  • Secure the cooler by screwing a simple strap over it.
  • Secure the damper with duct tape. Could also use glue.
The cold-sinks on the cooler module. These go inside of the holes, so that the cold sinks are inside the box, and the heat sinks are outside the box.
The cold sinks pushed inside the box
This is what the back of the container looks like with the heat sinks facing outward. The damper has also been inserted into the 4-inch hole.
Inside-view of the container's back. This shows the cold sinks that were pushed into the 3-inch holes, and the damper hthat was pushed into the 4-inch hole.
Duct tape secures the damper

On the bottom of the box, use a ducting shrowd to attach the 120mm fan

Ducting shrowd
Bottom of the container showing the outtake fan attached.

Your box is basically done now.

Now you need to build the control box and run the wires. This part is a bit arduous; patience is the key.

Note: I am using a servo driver as a PWM controller, but it might be overkill. I might modify this in the future to use PWM straight from the GPIO pins.

Note: You will need to solder a GPIO header onto your pi.

  • I used a shoe box, but I will modify this in the future to use proper project box
  • In the shoebox I have
    • 5 mosfets (Note: I will likely move these to the container)
    • 12v power supply
    • 5v buck converter
    • Rasberry pi with servo/pwm hat
    • LCD Screen
    • Three momentary switches (buttons) and a power switch
  • Now you just need to wire everything together. I will add details and photos as possible in the future. For now, I will just give it to you raw. If you don't understand electricity, you should probably wait for the detailed version.
    • 12vdc -> 5vdc buck converter
    • 12v+ -> All 12v components
    • 12v- -> Pi GND
    • 5vdc -> LCD screen
    • 5vdc -> Pi 5vdc
    • PWM 0 -> Outake fan
    • PWM 1 -> Circulation fan
    • PWM 2 -> 220Ω resistor -> Mosfet Gate
      • Moseft 12v- -> Peltier cooler cores (1 PWM signal for both cores) 12v-
    • I2C (sda+sdl) -> LCD, Sht30, Bme280
    • GPIO 17, 27, 22 -> 220Ω resistors -> Up, Down, Enter Button
      • Add 10kΩ pull down resistors to ground
    • GPIO 24 -> 220Ω resistor -> Mosfet Gate
      • Mosfet 12v- -> All peltier fans (hot and cold sinks) 12v-
    • GPIO 25 -> 220Ω resistor -> Mosfet Gate
      • Mosfet 12v- -> outtake fan 12v-
    • GPIO 20 -> 220Ω resistor -> Mosfet gate
      • Mosfet 12v- -> Damper open
    • GPIO 21 -> 220Ω resistor -> Mosfet gate
      • Mosfet 12v- -> Damper close
The control box. On the lid is an LCD, 3 buttons, and a power switch. Note: in this photo there is no buck converter. Instead we are using a separate 5v USB supply for the PI.