Environmental monitoring to welcome you home.
The title ambiainvis combines the Romansh words for environment (ambiaint) and welcome (bainvis).
- i2c_read_multiple.ino
| ID | I2C address | VCC | description |
|---|---|---|---|
| AT24C256 | 0x50 & 0x58 | 2.7 - 5.5 | EEPROM storage |
| SCD40 | 0x62 | 2.4 - 5.5 | CO2 sensor |
| HTU21_SHT21 | 0x40 | 3.3-5 | humidity & temperature sensor |
| SSD1306 | 0x3C | 3.3 - 5 | OLED display |
Block diagram converted to schematics & layout via EasyEDA.
How to connect Arduino Uno to I2C clock (SCL) and data (SDA) wires.
| Abbreviation | Description |
|---|---|
| TVOC | Total Volatile Organic Compound |
| eCO2 | Equivalent CO2 |
| NDIR | Non-Dispersive Infrared |
| VOC | Volatile Organic Compound |
https://en.wikipedia.org/wiki/Volatile_organic_compound https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor
SHT21 Humidity & Temperature sensor with HTU21 I2C level shifting circuitry to accept 3.3V-5V.
SHT21 specifications:
- Relative Humdity Range: 0% - 100%
- Relative Humdity Accuracy (Typical, 10% - 90%): ±2%
- Temperature Range: -40°C - 125°C
- Temperature Accuracy (Typical, 5°C - 60°C): ±0.3°C
- Voltage: 2.1V - 3.6V
- Current: 200µA - 300µA
Links
- Description: NDIR CO2 sensor
- CO2 Range: 0ppm - 40'000ppm
- CO2 Accuracy (400ppm - 2'000ppm): ±50ppm
- Relative Humdity Range: 0% - 100%
- Relative Humdity Accuracy (Typical, 15°C - 35°C, 20% - 65%): ±6%
- Temperature Range: -10°C - 60°C
- Temperature Accuracy (Typical, 15°C - 35°C): ±0.8°C
- Voltage: 2.4V - 5.5V
- Current (Typical, Periodic, 3.3V): 15mA
Links
- Interface: I2C
- CO2 Range: ???
- CO2 Accuracy: ???
- Voltage: ???
- Current: ???
https://aliexpress.com/item/1005003829532007.html
- Interface: ???
- Accuracy PM2.5: ???
- Voltage: ???
- Current: ???
https://aqicn.org/sensor/pms5003-7003/ https://aqicn.org/air/sensor/spec/pms5003-english-v2.3.pdf https://aqicn.org/air/sensor/spec/pms7003-english-v2.5.pdf
- Description: NVRAM - AT24C256
- Storage (Bytes): 256 KB
Links
- Description: OLED Display SSD1306
- Pixels: 128x64
Links
Outside (2023): 420 ppm Outside (1950): 311 ppm
https://www.volker-quaschning.de/datserv/CO2/index.php
- < 1'000 ppm: everything fine
- > 2'000 ppm: fresh air necessary
https://www.umweltbundesamt.de/sites/default/files/medien/pdfs/kohlendioxid_2008.pdf
- > 30'000 ppm / 30 minutes: intoxication
- > 70'000 ppm / 2 minutes: unconsciousness
- > 100'000 ppm: dangerous for life
https://www.cdc.gov/niosh/idlh/124389.html
- 30% - 65%: comfortable for humans
- > 60%: increased probability for molds
- 40% - 60% & 18°C - 23°C: ideal for wood (floor, furniture, ...), as wood does not contract/expand in this range
https://www.umweltbundesamt.de/sites/default/files/medien/publikation/long/2885.pdf https://www.umweltbundesamt.de/themen/faq-absenkung-der-raumtemperatur-in-herbst-winter https://www.venta-air.com/en_de/Usage/Humidity-for-wooden-floors-and-furniture/
Circuit diagram and layout were created with EasyEDA.
- load code onto Arduino
- launch python
- optionally check if installed
sudo apt install python3
// --------------------------------------
// i2c_get_address.ino
//
// used to get unique address of i2c device
//
// Version 1
// This program (or code that looks like it)
// can be found in many places.
// For example on the Arduino.cc forum.
// The original author is not known.
// Version 2, Juni 2012, Using Arduino 1.0.1
// Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26 2013
// V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
// by Arduino.cc user Krodal.
// Changes by louarnold removed.
// Scanning addresses changed from 0...127 to 1...119,
// according to the i2c scanner by Nick Gammon
// https://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
// As version 4, but address scans now to 127.
// A sensor seems to use address 120.
// Version 6, November 27, 2015.
// Added waiting for the Leonardo serial communication.
//
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//
#include "/usr/share/arduino/hardware/arduino/avr/libraries/Wire/src/Wire.h"
void setup() {
Wire.begin();
Serial.begin(9600);
while (!Serial); // Leonardo: wait for Serial Monitor
Serial.println("\nI2C Scanner");
}
void loop() {
int nDevices = 0;
Serial.println("Scanning...");
for (byte address = 1; address < 127; ++address) {
// The i2c_scanner uses the return value of
// the Wire.endTransmission to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
byte error = Wire.endTransmission();
if (error == 0) {
Serial.print("I2C device found at address 0x");
if (address < 16) {
Serial.print("0");
}
Serial.print(address, HEX);
Serial.println(" !");
++nDevices;
} else if (error == 4) {
Serial.print("Unknown error at address 0x");
if (address < 16) {
Serial.print("0");
}
Serial.println(address, HEX);
}
}
if (nDevices == 0) {
Serial.println("No I2C devices found\n");
} else {
Serial.println("done\n");
}
delay(5000); // Wait 5 seconds for next scan
}