CO2 sensor

Breathe better

Elevated levels of CO2 can influence how you feel.

Wake up refreshed

If your bedroom has a high CO2 levels at night, this may cause  headaches. 

M‌ake it smart 

Automatically open a window when CO2 levels get too high.

Disable data transmission

The built-in screen shows measurements directly.

Can generate fake data

Generate data that looks like levels are holding steady.

Voice control

Sometimes you don't want to measure everything that happens in your home. In those cases it's easy to disable data transmission of the sensor, for example through voice control.

Candle's voice control is fully local - it doesn't make any connection to the internet.

  • CO2 sensor

    Created by artist and jeweler Dinie Besems

    Learn more
  • CO2 sensor

    Created by designer Jesse Howard

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  • Inside Jesse's CO2 sensor

    Press the little button to generate fake data

    Learn more

Why can this sensor generate fake data?

The CO2 levels in your home go up if more people are present. This means the CO2 sensor can also be used as a people counter. 

Young adults should be able to bring over friends, or a date, without this being immediately readable to the parents. We believe this is vital to healthy social development.

‌ Sometimes a smart home can measure too much.

Learn more

Creating the sensor

A‌proximate build and install time: 10 to 20 minutes.

Connect the CO2 sensor

Connect the sensor's TX (Transmit) pin to signal pin 5 on the expansion board.
Connect the sensor's RX (Receive) pin to signal pin 6 on the expansion board.

Connect the sensor's VCC (positive) pin to any VCC (positive, red) pin on the expansion board. 
Connect the sensor's GND (ground) pin to any GND (ground, black) pin on the expansion board. 

Connect the OLED display

Connect the display's SDA (Signal Data) pin to signal pin A4 on the expansion board.
Connect the display's SCK (Signal Clock) pin to signal pin A5 on the expansion board.

Connect the display's VD0 (positive) pin to any V (positive, red) pin on the expansion board. 
Connect the display's GND (ground) pin to any G (ground, black) pin on the expansion board. 

Plug in the Arduino

Plug in the RF-Nano Arduino

Plug the RF-Nano into its socket. The USB connector should be on the outside of the main board.

Open the Candle Manager

Select the Candle Manager from the menu, and follow the steps. It will help you upload the code to your new creation.

Add your new device

Visit the Candle controller and on the things page press the (+) icon. Your new creation should be available. Optionally, select which of its properties you'd like to have in the spotlight. Click on "save" to complete the proces.

Shopping list

You can buy all the parts yourself, for example on
CO2 sensor module
Mar 22, 2019

This MH-Z19B module uses infrared to measure CO2 levels. This allows it to work accurately for a very long time. There are…

Small OLED screen
Jan 21, 2019

This small screen is built with OLED technology. It uses very little power.

RF-Nano Arduino
Aug 10, 2018

The RF-Nano is an Arduino Nano with built-in wireless connectivity. It's the brain of all Candle devices.

Dupont wire
Aug 09, 2018

These wires allow you to easily connect the main board to sensors and actuators. They snugly fit over the pins. No soldering…

Expansion board
Aug 06, 2018

This expansion board makes it easy to connect everything by just plugging in wires.