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Project development

Week 19


what tasks have been completed, and what tasks remain?

The pot for the plant is made, and the wooden box that will carry the components as well.

The microcontroller is working and reads the CO2 values indoor our house.

I still have trouble programming my wifi card.

The APP is working and provisionally used a wifi for arduino to receive the CO2 values, and send it to the APP.

what has worked? what hasn't?

Everything worked, and it did not always work at first, but with several attempts I was able to do everything.

Making the wifi module that I designed to receive data is my big problem.

what questions need to be resolved?

None! But I continue to have problems with my Wifi module.

what will happen when?

The final project is complete! While the vessel I designed is working, it is possible to see through APP the concentration of CO2 gas that exists indoor our homes. This allows us to take into account the quality of the air we breathe for the sake of our health and well being.

what have you learned?

In these months I learned electronics! I learned how to make it! I work with a lot of diferents machines!

I thought... I designed it... and I managed to get my prototip. It's Fantastic!

With my final project I learned about the importance of renewing the air inside our homes in order to have a healthy health.

I made models in the laser machine... I made molds to get several prototypes of vases... I designed a CO2 module... I made my own microcontroller, and wifi. And I connected everything!

An excellent job!


Indoor air is 5 times more polluted than the atmospheric air, and this can bring serious problems for human health.

Plants are a great way to avoid these problems.

The plants inside our homes are natural filters that are cleaning toxic components of the air and producing oxygen


Prototype Box for eletronics

Step1- Design

I started by design several types of box, in the program Rhinoceros 3D

After that I planned the laser cutting boxes. So that all sides fit into one another, and are easy to assemble.

Step2- CNC Cut

The pieces of the sides of the box were cut in the machine lase, in mdf wood of 3mm. And on some faces of the box to be more consistent I joined two pieces with 3mm.


I put the pieces of the box through the grooves and put a bit of glue to make sure they look good together.

The box will have electronic components inside and a plant pot on top that will requires water. It is therefore important that the mdf box is sealed.

Final Project related assignments:

Prototype Planter

Step1- Design

It is necessary to make a vase to place the plant.

Initially, I made a wooden vase using the same process as the electronics box. But then I decided to build a mold from the previous piece in 3mm mdf and create a plastic vase.

Step2- CNC cut

In addition to the model of the vase that was cut in pieces in the laser cutting machine and mounted. I did and cut a larger cube and smaller cube on the laser.

Step3- Assembly

The pieces were joined together by the fittings and with the help of some glue.

Step4- Molding and casting

It is necessary to make the mold of the vessel in silicone and then to pour the plastic material.

I placed the wooden model of the vase inside the larger box, and the smaller box inside the model of the vase, so as to make the mold and the counter-mold of the vase.

After that I filled the two areas with the silicone and I wait for it to be dry. I dumped the plastic-resin mold and got my plastic vase.

Step5- Grow plant

With my planter made I could start growing my plants :)

Find the files used and download here:

  • week3_planter_lasercutting.3dm _3DRhino Files
  • week3_planter_lasercutting.AI _AI Files
  • Eletronics


    Step1 - Draw

    I drew my microcontroller board with an ATtiny 44 because I needed a few output pins.

    The board has a digital pin, two analog pins, 3 LEDS RX, TX, FTDI communication, and pins to the ISP programmer.

    Step2- Electronic production (milling + solder)

    The board was cut into the milling machine, and then cleaned and welded all the components.

    Step3 - program the code

    The code was programmed in the arduino IDE.

    Download files:

  • Microcontroller.brd _Eagle Files
  • Microcontroller.sch _Eagle Files

  • Co2 module

    Step1 - Draw

    I desgin a co2 sensor for the week of the input devices.

    I used as reference the sensor MQ135 that allows to read some gases present in the air, like the carbon dioxide.

    The sensor works simply. It just needs energy to heat the resistance it has inside.

    The sensor is analog and has 6 pins, 3 connected to the VCC, 2 connected to the GND and a pin A connected to the analog pin with a resistor.

    Step2- Electronic production (milling + solder)

    The board was cut into the milling machine, and then cleaned and welded all the components.

    Step3 - program the code

    The code was programmed in the arduino IDE.

    Download files:

  • MQ135.brd _Eagle Files
  • MQ135.sch _Eagle Files
  • _Arduino Files

  • Bluetooth module

    I thought it would be a good and simple option to use bluetooth in my project

    Bluetooth module works by TX-RX communication, and both can work with 3.3V or 5V power.

    For starting to use bluettoth module wih my microcontroller Attiny44, I conect:

  •  pin4- RX - SCL/SCK (from 44 attiny) to RX (from bluetooth)
  • pin8 - TX - SDA/MOSI (from attiny 44) to TX (from bluetooth)
  •  GND (from 44 attiny) to GND (from bluetooth)
  •  VCC (from attiny 44) to VCC (from bluetooth)

  • After that I sent a simple code to see if the conection between microcontroller-bluetooth was correct. See the code here

  • week16_bluetooth_test

  • This time the code worked and the data was sent.

    The code was programmed in the arduino IDE.

    To know more about bluetooth communication visit:

  • week 6. Interface and application programming
  • Communication

    Step 1 - Receive and analyze co2 data

    The carbon dioxide concentration data that the MQ135 sensor reads from the air in our homes are received by the microcontroller and are analyzed and calibrated to a correct and reliable value.

    Step2 - Send data from bluetooth

    Then this data is sent through the bluetooth module to an application on the mobile phone, made in APP Inventor.

    Step 3- design and program an APP

    I used as an alternative the APP Inventor that detects the bluettoth module.

    I sent the data in real time the percentage of carbon dioxide.

    In addition to reading the CO2 sensor I want the leds that I have implemented in my microcontroller to light showing that the air inside our homes is healthy or harmful to our health, so if you turn on the LEDs means:

  • Blue LED - means CO2 is less than 800ppm and it is good for health

  • Yellow LED - means CO2 is less than 800ppm and greater than 1200ppm and you have to be careful about health

  • Red LED - means CO2 is greater than 1200ppm and is harmful to health

  • The final code I sent was:

  • week16_bluetooth_co2

  • It is necessary to have bluetooth in your mobile phone and to pair it with the bluetooth to which the microcontroller is connected, through the menu to connect the bluetooth that we created in the APP. .

    The video below shows the connection of my microcontroller, with the sensor and the bluettoh

    Our halite contains a large percentage of co2 so when blowing into the sensor, the values increase.

    Final Project related assignments:

  • week 16. Interface and application programming
  • week 17. Applications and implications


    More details about the project in:

  • Final Project