Published May 16, 2020 © Apache-2.0

Indoor-air-quality-traffic-light

Indoor air quality traffic light with display and Mqtt support ( ESP32, BME280, CCS811, TM1637, Neopixel, Mqtt) with Micropython

IntermediateProtip3 hours1,036

Things used in this project

Hardware components

ESP 32 Dev Kit C

LED Stick, NeoPixel Stick

BME280 Temp Sensor

7 Segment Display with tm 1637

CJMCU CCS811 sensor

PCB Boards

Case Led Lightbox

Story

Indoor-air-quality-traffic-light

Indoor air quality traffic light with display and Mqtt support ( ESP32, BME280, CCS811, TM1637, Neopixel, Mqtt)

1 / 2

ESP32 measures the quality of indoor air with a CCS811 and BME280. The measurements are visualized with a neopixel strip and a 7 segment display.

The data can also be sent via Wlan and Mqtt

Attention the measurements are not calibrated and are more than tendency than absolute values!

Nevertheless it can be determined when it is useful to ventilate. Especially with regard to Covid and other cold viruses.

As housing a Led Illuminated marking field was used. This is available in many variations among others with letters.

In the code you have to declare if you want to use the Wifi.

If the wifi is active, the SSID, wifi password and the MQTT parameters must be entered. (See comments config)

To get started:

If your ESP dosent have Micropython

Install Micropython on the ESP32

a good tutorial about it : https://docs.micropython.org/en/latest/esp32/tutorial/intro.html

I prefer Thonny https://thonny.org with Micropython addons

In the main.py you have to enter the following under ####Config###

The parameters for Wifi and Mqtt can be adjusted.If Wifi should not be used set wifi_enable = False.

####config start#######

#config Wifi
wifi_enable = True  #True or False 
wifi_ssid = "yourSSID"
wifi_password = "yourPassword"

#config MQTT
mqtt_client = "yourClientName"
mqtt_broker = "yourBrokerIP"
mqtt_user = "yourMqttUser"
mqtt_password = "yourMqttPassword"
mqtt_port = 1883

#def MQTT  Topic
topic_co2 = b"home/livingroom/co2"
topic_tvoc = b"home/livingroom/tvoc"
topic_temp =  b"home/livingroom/temperature"
topic_humidity =  b"home/livingroom/humidity"
topic_press = b"home/livingroom/pressure"

####config end#######

Import the main.py and the libraries tm1637.py, CCS811.py, bme280.py to the board.

Switch off the board and connect the parts to the board.

Connect CCS811, BME280 to 3.3V / GND / SCL pin 13 /SDA pin 5

Connect neopixel to 5V / GND / Pin 19

Connect TM1637 7Digit to 3, 3V / GND / CLK Pin 17 /DIO Pin 18

A beautiful housing with a translucent front makes it very nice for living rooms.

That's it.

Now connect the board via a Powerbank or USB power supply. The sensor now shows the air quality as a traffic light and the temperature as a value and sends the data via Mqtt to the broker. If the traffic light is red you should ventilate. If the light is yellow it is ok, if it is green the air quality is good.

Attention the CCS811 sensor needs a BurnIn for 24h when it is new. Also after switching off the sensor it needs about 30 min until the data has settled down.

Have fun with the sensor traffic light and stay healthy

Code

main.py

from machine import Pin ,I2C , WDT , reset
from umqtt.simple import MQTTClient
import ubinascii
import neopixel
import tm1637
import time
import network
import CCS811
import bme280

####config start#######


#config Wifi
wifi_enable = False  #True or False for using Wifi
wifi_ssid = "yourSSID"
wifi_password = "yourWifiPassword"

#config MQTT
mqtt_client = "yourMqttClientName"
mqtt_broker = "yourMqttBrokerIP"
mqtt_user = "yourMqttUser"
mqtt_password = "yourMqttPassword"
mqtt_port = 1883


#def MQTT  Topic
topic_co2 = b"home/livingroom/co2"
topic_tvoc = b"home/livingroom/tvoc"
topic_temp =  b"home/livingroom/temperature"
topic_humidity =  b"home/livingroom/humidity"
topic_press = b"home/livingroom/pressure"


####config end#######


#init Watchdog 10 sec
wdt = WDT(timeout=60000)
print("init sw watchdog ")

#NeoPixel def
pin = Pin(19,Pin.OUT)
np = neopixel.NeoPixel(pin, 8)

#7Segment def
tm = tm1637.TM1637(clk=Pin(17), dio=Pin(18))

#CCS811 def
i2c = I2C(scl=Pin(13), sda=Pin(5))
# Adafruit sensor breakout has i2c addr: 90; Sparkfun: 91
s = CCS811.CCS811(i2c=i2c, addr=90)

#BME280 def
bme = bme280.BME280(i2c=i2c)

# clear NeoPixel
def np_clear():    
    for i in range(8):
        np[i] = (0, 0, 0)
        np.write()
        
np_clear()  # clear
        

#def state for first run
state = 0

#def for use wifi
def connect_wifi():
    
    sta_if = network.WLAN(network.STA_IF)
    sta_if.active(True)
    if not sta_if.isconnected():
        print("connecting to wlan...")
        sta_if.connect(wifi_ssid, wifi_password)
        while not sta_if.isconnected():
            time.sleep(10)
            pass
    print(sta_if.ifconfig())


def check_wifi():
    sta_if = network.WLAN(network.STA_IF)
    if sta_if.isconnected() == True:
        return True
    else:
        return False
    

def restart_and_reconnect():
    try:
        print("failed to connect to MQTT broker . Reconnecting...")
        time.sleep(10)
        reset()
    except OSError as e:
        restart_and_reconnect()


#create MQTT client
client = MQTTClient(mqtt_client, mqtt_broker ,user=mqtt_user, password=mqtt_password, port=mqtt_port)


def check_co2():
    try:
        if s.data_ready():
            data_eCO2_tVOC = [s.eCO2, s.tVOC]
            return data_eCO2_tVOC
            time.sleep(1)

    except:
        print ("Error read CCS811")


def sub_neopixel_room_ambient(eCO2 , tVOC):
    global state
    co2_value = int(eCO2)
    print("eCO2_value: %s , tVOC_value: %s " % (eCO2,tVOC) )
     
    if co2_value  >= 1500:
        #print("open the windows!")
        for i in range(8):
            np[i] = (16,0,0)
        #red alert
        np.write()
        state = 1
    elif co2_value >= 900:
        #print("mid air quailty")
        for i in range(8):
            np[i] = (32,16,0)
        #yellow 
        np.write()
        state = 1
    elif co2_value < 900:
        #print("good air quality")
        for i in range(8):
            np[i] = (0,16,0)
        #green 
        np.write()
        #tm.show(str(co2_value))
        state = 1
        
    elif state == 0:
        print("no data aviable")
        n=np.n
        # bounce
        for i in range(2 * n):
            for j in range(n):
                np[j] = (8, 0, 16)
            if (i // n) % 2 == 0:
                np[i % n] = (0, 0, 0)
            else:
                np[n - 1 - (i % n)] = (0, 0, 0)
            np.write()
            time.sleep_ms(60)
    
    
    
def  sub_display_7digit( temp):   #display data on 7Segment
    print("Bme280 Temp: %s " % temp)
    temp_value = temp
    temp_value = str(temp_value).replace(".","C")
    tm.show(temp_value)
    #print((temp_value))


# let's go


if state == 0:
    tm.show("Test")
    
    n=np.n
    # bounce for test neopixel
    for i in range(2 * n):
        for j in range(n):
            np[j] = (0, 0, 8)
        if (i // n) % 2 == 0:
            np[i % n] = (0, 0, 0)
        else:
            np[n - 1 - (i % n)] = (0, 0, 0)
        np.write()
        time.sleep_ms(30)
    
connect_wifi() 

measure_time = time.ticks_ms() 
send_data_time = time.ticks_ms() 
    
while 1:
    
    try:
        #15 min = 900000 millisec
        #1 min = 60000 millisec
        delta_measure = time.ticks_diff(time.ticks_ms(), measure_time)
        
        delta_send_data = time.ticks_diff(time.ticks_ms(), send_data_time)
        
                
        if delta_measure >= 60000 or state == 0: # 1 min = 60000 millisec or if state == 0  while first run then check the sensors
                
            #measure bme280
            r = bme.read_compensated_data()
            t = r[0]/100           
            t = t - 2  #offset TempSensor 
            p = r[1]/25600
            h = r[2]/1024
                
            s.put_envdata(humidity=h,temp=t)
            
            #measure ccs811
            air_data = check_co2()
            
            if air_data is not None  :
                # neopixel write
                sub_neopixel_room_ambient(air_data[0],air_data[1])
                
                
                # 7 digit write
                sub_display_7digit(t)

                measure_time = time.ticks_ms() 
                
                if wifi_enable == True:
                    
                
                    if check_wifi() == True and delta_send_data >= 900000 :   # 15 min = 900000 millisec
                        try:
                            client.connect()
                            client.publish(topic_co2, str(air_data[0]))
                            time.sleep(0.5)
                            client.publish(topic_tvoc, str(air_data[1]))
                            time.sleep(0.5)
                            client.publish(topic_temp, str(t))
                            time.sleep(0.5)
                            client.publish(topic_humidity,str(h))
                            time.sleep(0.5)
                            client.publish(topic_press,str(p))
                            time.sleep(0.5)
                        
                            send_data_time = time.ticks_ms() 
                            client.disconnect()
                        
                        except:
                            restart_and_reconnect()
                        
                    elif delta_send_data >= 900000:
                        
                        send_data_time = time.ticks_ms() 
                        
                    
                
                
            else :
                pass
                
        
        
        wdt.feed()
            
 
           
    except OSError as e:
        print("Error while loop")

Credits

DAN B.

5 projects • 3 followers

Indoor-air-quality-traffic-light

Things used in this project

Hardware components

Story

Indoor-air-quality-traffic-light

To get started:

Schematics

Schematic

Code

main.py

Github Link to the Projekt

Credits

DAN B.

Comments

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Indoor-air-quality-traffic-light

Indoor-air-quality-traffic-light

Things used in this project

Hardware components

Story

Indoor-air-quality-traffic-light

To get started:

Schematics

Schematic

Code

main.py

Github Link to the Projekt

Credits

DAN B.

Comments

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