Project Documentation

WiFi LoRa Environmental Monitoring System with INMP441 Mic and Multiple Sensors

Circuit Documentation

Summary

This document provides a detailed overview of a circuit designed to collect environmental data using various sensors and transmit the data via a LoRa module. The circuit includes a microphone, UV light sensor, air quality sensor, temperature/pressure/humidity sensor, and a solar power management system. The data is processed by a microcontroller and sent over a LoRa network.

Component List

INMP441 FRONT MIC
- Description: Digital MEMS microphone
- Pins: L/R, WS, SCK, SD, VDD, GND
WiFi Lora 32V3
- Description: Microcontroller with WiFi and LoRa capabilities
- Pins: pin 1 to pin 36
CJMCU-811
- Description: Air quality sensor
- Pins: VCC, GND, SCL, WAK, INT, RST, ADD, SDA
BME/BMP280
- Description: Temperature, pressure, and humidity sensor
- Pins: GND, SCL, SDA, VIN
Adafruit LTR390 UV Light Sensor
- Description: UV light sensor
- Pins: VCC, 3.3V, GND, SCL, SDA, INT
Solar Power Manager V5
- Description: Solar power management module
- Pins: Solar -, Solar +, Battery -, Battery +, USB -, USB +
Solar Panel
- Description: Solar panel for power generation
- Pins: +, -
Air Quality Sensor
- Description: Air quality sensor
- Pins: TX, 5V, GND, RX
18650 in Holder
- Description: 18650 battery holder
- Pins: GND, VCC
Micro USB to Cable (2 Pin)
- Description: Micro USB to 2-pin cable
- Pins: Micro USB, +, -
USB Power
- Description: USB power source
- Pins: +, -

Wiring Details

INMP441 FRONT MIC

L/R: Connected to GND
WS: Connected to WiFi Lora 32V3 pin 7
SCK: Connected to WiFi Lora 32V3 pin 3
SD: Connected to WiFi Lora 32V3 pin 9
VDD: Connected to WiFi Lora 32V3 pin 17
GND: Connected to GND

WiFi Lora 32V3

pin 1: Connected to SDA of Adafruit LTR390 UV Light Sensor, CJMCU-811, BME/BMP280
pin 3: Connected to SCK of INMP441 FRONT MIC
pin 7: Connected to WS of INMP441 FRONT MIC
pin 9: Connected to SD of INMP441 FRONT MIC
pin 17: Connected to VDD of INMP441 FRONT MIC, VCC of Adafruit LTR390 UV Light Sensor
pin 18: Connected to GND
pin 19: Connected to GND of Air Quality Sensor, CJMCU-811
pin 20: Connected to 5V of Air Quality Sensor
pin 27: Connected to SCL of Adafruit LTR390 UV Light Sensor, CJMCU-811, BME/BMP280
pin 36: Connected to RX of Air Quality Sensor
pin 35: Connected to TX of Air Quality Sensor

CJMCU-811

VCC: Connected to VIN of BME/BMP280, WiFi Lora 32V3 pin 16
GND: Connected to GND of Air Quality Sensor, WiFi Lora 32V3 pin 19
SCL: Connected to SCL of Adafruit LTR390 UV Light Sensor, BME/BMP280, WiFi Lora 32V3 pin 27
SDA: Connected to SDA of Adafruit LTR390 UV Light Sensor, BME/BMP280, WiFi Lora 32V3 pin 1

BME/BMP280

GND: Connected to GND
SCL: Connected to SCL of Adafruit LTR390 UV Light Sensor, CJMCU-811, WiFi Lora 32V3 pin 27
SDA: Connected to SDA of Adafruit LTR390 UV Light Sensor, CJMCU-811, WiFi Lora 32V3 pin 1
VIN: Connected to VCC of CJMCU-811, WiFi Lora 32V3 pin 16

Adafruit LTR390 UV Light Sensor

VCC: Connected to VDD of INMP441 FRONT MIC, WiFi Lora 32V3 pin 17
GND: Connected to GND
SCL: Connected to SCL of CJMCU-811, BME/BMP280, WiFi Lora 32V3 pin 27
SDA: Connected to SDA of CJMCU-811, BME/BMP280, WiFi Lora 32V3 pin 1

Solar Power Manager V5

Solar -: Connected to - of both Solar Panels
Solar +: Connected to + of both Solar Panels
Battery -: Connected to GND of 18650 in Holder
Battery +: Connected to VCC of 18650 in Holder

Solar Panel

-: Connected to Solar - of Solar Power Manager V5
+: Connected to Solar + of Solar Power Manager V5

Air Quality Sensor

RX: Connected to WiFi Lora 32V3 pin 36
TX: Connected to WiFi Lora 32V3 pin 35
5V: Connected to WiFi Lora 32V3 pin 20
GND: Connected to GND of CJMCU-811, WiFi Lora 32V3 pin 19

18650 in Holder

GND: Connected to Battery - of Solar Power Manager V5
VCC: Connected to Battery + of Solar Power Manager V5

Micro USB to Cable (2 Pin)

+: Connected to + of USB Power
-: Connected to - of USB Power

USB Power

+: Connected to + of Micro USB to Cable (2 Pin)
-: Connected to - of Micro USB to Cable (2 Pin)

Code Documentation

Main Code

import time
from machine import Pin, SoftI2C, SoftSPI, I2S
from lib import ssd1306, sx127x
import bme280
import ltr390
import ccs811
import network
import array
import math

# --- LoRa Sender Konfiguration ---
device_config = {
    'miso': 19,
    'mosi': 27,
    'ss': 18,
    'sck': 5,
    'dio_0': 26,
    'reset': 14,
    'led': 25,
}

lora_params = {
    'frequency': 86965E4,
    'tx_power_level': 14,
    'signal_bandwidth': 125E3,
    'spreading_factor': 8,
    'coding_rate': 5,
    'preamble_length': 8,
    'implicit_header': False,
    'sync_word': 0x12,
    'enable_CRC': False,
    'invert_IQ': False,
}

device_spi = SoftSPI(
    baudrate=10000000,
    polarity=0, phase=0, bits=8, firstbit=SoftSPI.MSB,
    sck=Pin(device_config['sck'], Pin.OUT, Pin.PULL_DOWN),
    mosi=Pin(device_config['mosi'], Pin.OUT, Pin.PULL_UP),
    miso=Pin(device_config['miso'], Pin.IN, Pin.PULL_UP)
)

lora = sx127x.SX127x(device_spi, pins=device_config, parameters=lora_params)

# --- Sensor Konfiguration ---
i2c = SoftI2C(scl=Pin(22), sda=Pin(21))

bme = bme280.BME280(i2c=i2c)
ltr = ltr390.LTR390(i2c)
ccs = ccs811.CCS811(i2c)

# --- Mikrofon I2S Konfiguration ---
mic_sck_pin = Pin(12)
mic_ws_pin = Pin(25)
mic_sd_pin = Pin(32)

audio_in = I2S(
    0,
    sck=mic_sck_pin,
    ws=mic_ws_pin,
    sd=mic_sd_pin,
    mode=I2S.RX,
    bits