Digital pet - Indoor Air Quality gamified - SEN66

Taking care of this digital pet is taking care of you! Monitor your indoor air quality to keep it alive. IAQ gamified for kids.

IntermediateFull instructions provided8 hours204

Digital pet - Indoor Air Quality gamified - SEN66

Things used in this project

Hardware components

Raspberry Pi 5

Sensirion SEN66

Seeed Studio Grove SEN5X

Seeed Studio Grove SCD41

Story

As much as I would love to take care of my indoor air quality, I simply don't.

During the day, I am busy with my work/tasks mostly and simple actions such as opening the windows or turning on the humidifier unfortunately slip my mind. I am guessing that it happens to a lot of us in home offices. I didn't invest yet in automated appliances. Indoor air quality is just one more thing on the mental load and to be honest, it is not very fun. How to make taking action for my health more fun? While this problem statement applies to my situation, it is actually critical to make indoor air quality topics accessible to children.

Indoor air quality is often overlooked in early education, yet it plays a vital role in children's health and learning. Introducing this topic to kids in a simple, relatable way helps them understand how the air around them affects their daily lives. By making IAQ accessible early on, we can build awareness that lasts a lifetime.

Raising awareness about indoor air quality (IAQ) is crucial for children because their developing lungs and immune systems make them more vulnerable to the effects of poor air. Children spend a significant amount of time indoors—at school, at home, and in daycare—where air pollutants like carbon dioxide, dust, mold, and volatile organic compounds can impact their health, concentration, and cognitive development. By teaching kids about IAQ in a fun and engaging way, we empower them to recognize the importance of fresh, clean air and encourage habits that support healthier environments, ultimately fostering both well-being and environmental responsibility from a young age.

Let me introduce you to: ChampIAQ (in french "shroom" = "champi" hence the name)

Similar to Tamagotchi characters, ChampIAQ is a cute digital pet. You are tasked with one mission: taking care of his flower garden that is very dear to him. Each flower represents an indoor air parameter: VOC, NOX, Particulate matter, Humidity and CO2. If one of the parameters is not optimal, ChampIAQ gets mad and loses one heart. ChampIAQ only has 3 hearts so be careful, more than 3 parameters in the red and you just killed our little mushroom friend. :(

ChampIAQ is dead since 3 IAQ parameters are not optimal

ChampIAQ digital pet at different stages

I think it blends very well in my home office setup. It helps me to be conscious about my air quality and motivates me to take action. Taking care of ChampIAQ is taking care of me! Problem solved.

ChampIAQ on my desk setup

How it works?

For this project, I used a Raspberry Pi 5, a 5-inch display and the newest environmental sensor node from Sensirion, the SEN66. The SEN66 is an all-in-one compact sensor that can measure up to nine environmental parameters (PM1, PM2.5, PM4, PM10, T, RH, VOC Index, NOx Index, CO2). At the moment (June 2025), it is only available as an evaluation kit: SEK-SEN66 - Evaluation kit SEN60, SEN65, SEN66. The SEN55 (NOX,VOC,PM,RH,T) and SCD41 (CO2) can be used as an alternative. Seeed studio offers those sensors with convenient grove connectors, plug-and-play.

When all the indicators are good, ChampIAQ is happy and all the flowers are bloomed.

If one of the parameters needs attention, the flower fades and a little speech bubble appears with the action item needed.

An example below is a video of the CO2 flower fading as I blow on the sensor to increase the CO2 levels.

Video of the fading transition of the CO2 flower

If all the flowers fade, the garden is filled with dead flowers and our little friend goes from happy, to mad, to dead.

1 / 4 • ChampIAQ frames depending on the air quality

Indoor Air Quality Parameters:

Humidity: ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) recommends indoor humidity levels between 30% and 60%. My indoor air tends to be too dry due to my air conditioning system. If the humidity falls below 30%, I should turn on my humidifier.
CO2: CO2 buildup is a sign of poor ventilation and can negatively impact the health. High levels of CO2 can cause symptoms such as headaches, dizziness and reduced cognitive ability (poor concentration, less efficient decision making...). ASHRAE recommends maintaining indoor CO2 levels below 1, 000 parts per million (ppm) as a guideline for acceptable indoor air quality in buildings.
VOC and NOX: VOC and NOX are gases and chemicals that can be harmful. For health and smell, it is recommended to ventilate the room or purify the air if high levels are detected. The SEN66 outputs gas indexes that allows the detection of gas events while accounting for the air background.
Particulate matter: PM2.5 are particles of a diameter of 2.5 micrometres or smaller. Due to their size, they are inhalable and are small enough to pass through the lungs, into the bloodstream, and into your organs. High continuous exposure can lead to health issues and respiratory diseases. They are also an indication of allergens such as pollen, mites, dust and mold spores. Levels at or above 35 µg/m³ over a 24-hour period are considered unhealthy.

After fetching the data from the sensor, I am checking if the values are above a defined threshold. This function returns flags, if the threshold is reached, the corresponding flag equals 1. The flags are driving the user interface interaction.

def sen66_analyze():
    voc, nox, temperature, humidity,co2,pm2p5 = sen66_measure()  
    humidity = 1 if humidity < 30 else humidity = 0   
    co2 = 1 if co2 > 1000 else co2 = 0   
    voc = 1 if voc > 105 else voc = 0   
    nox = 1 if nox > 5 else nox = 0
    pm2p5 = 1 if pm2p5 > 35 else pm2p5 = 0
    return voc, nox, humidity,co2,pm2p5

Let me know if you decide to create your own IAQ digital pet, for you, your kids or your classroom!

It would be a great class workshop as the kids can draw the flowers and characters, learn a bit about sensors and electronics and learn about indoor air quality. What I love the most: mixing creativity and electronics!

Code

SEN66_sensor_readings

import time
from smbus2 import SMBus, i2c_msg

DEVICE_BUS = 1

# device address SEN66
DEVICE_ADDR = 0x6B

def sen66_init():
    global bus
    # init I2C
    bus = SMBus(DEVICE_BUS)

    # wait 1 s for sensor start up 
    time.sleep(1)

    # start continuous measurement in periodic mode, will update every s
    msg = i2c_msg.write(DEVICE_ADDR, [0x00, 0x21])
    bus.i2c_rdwr(msg)

    # wait for first measurement to be finished
    time.sleep(2)

def sen66_measure():
    global bus
    # read out sensor data
    msg = i2c_msg.write(DEVICE_ADDR, [0x03, 0x00])       
    bus.i2c_rdwr(msg)
    # wait 20 ms for data ready
    time.sleep(0.02)

    # read bytes; each three bytes in as a sequence of MSB, LSB, CRC
    msg = i2c_msg.read(DEVICE_ADDR,27)
    bus.i2c_rdwr(msg)

    # merge byte x and byte x+1 to integer
    pm1p0 = (msg.buf[0][0] << 8 | msg.buf[1][0])/10
    pm2p5 = (msg.buf[3][0] << 8 | msg.buf[4][0])/10
    pm4p0 = (msg.buf[6][0] << 8 | msg.buf[7][0])/10
    pm10p0 = (msg.buf[9][0] << 8 | msg.buf[10][0])/10

    humidity = msg.buf[12][0] << 8 | msg.buf[13][0]
    # calculate relative humidity according to datasheet in %
    humidity /= 100

    temperature = msg.buf[15][0] << 8 | msg.buf[16][0]
    # calculate temperature  according to datasheet in Celsius
    temperature /= 200

    voc = (msg.buf[18][0] << 8 | msg.buf[19][0]) / 10 #VOC index
    nox = (msg.buf[21][0] << 8 | msg.buf[22][0]) / 10 #NOX index
    co2 = (msg.buf[24][0] << 8 | msg.buf[25][0]) #ppm
    
    print("{:.2f},{:.2f},{:.2f},{:.2f},{:.2f},{:.2f}".format(voc, nox, temperature, humidity,co2,pm2p5))
    return voc, nox, temperature, humidity,co2,pm2p5

def sen66_analyze():
    voc, nox, temperature, humidity,co2,pm2p5 = sen66_measure()
    
    humidity = 1 if humidity < 40 else humidity = 0   
    co2 = 1 if co2 > 1000 else co2 = 0   
    voc = 1 if voc > 105 else voc = 0   
    nox = 1 if nox > 5 else nox = 0
    pm2p5 = 1 if pm2p5 > 35 else pm2p5 = 0
    print(voc, nox, humidity,co2,pm2p5)
    return voc, nox, humidity,co2,pm2p5
    
def sen66_deinit():
    global bus
    bus.close()