To monitor home or office dust density. We can use wemos d1, DHT22.
Youtube Video : https://youtu.be/f6huNqHjTiE
Wemos D1 :
- 11 digital input/output pins, all pins have interrupt/pwm/I2C/one-wire supported(except for D0)
- 1 analog input(3.2V max input)
- Micro USB connection
- Power jack, 9-24V power input.
- Compatible with Arduino
- Compatible with nodemcu
Microcontroller --> ESP-8266EX
Operating Voltage --> 3.3V
Digital I/O Pins --> 11
Analog Input Pins --> 1(Max input: 3.2V)
Clock Speed --> 80MHz/160MHz
Flash --> 4M bytes
Length --> 68.6mm
Width --> 53.4mm
Weight --> 25g
PinPin | Function | ESP-8266
TX | TXD | TXD
RX | RXD | RXD
A0 | Analog input, max 3.3V input | A0
D0 | IO | GPIO16
D1 | IO, SCL | GPIO5
D2 | IO, SDA | GPIO4
D3 | IO, 10k Pull-up | GPIO0
D4 | IO, 10k Pull-up, BUILTIN_LED | GPIO2
D5 | IO, SCK | GPIO14
D6 | IO, MISO | GPIO12
D7 | IO, MOSI | GPIO13
D8 | IO, 10k Pull-down, SS | GPIO15
G | Ground | GND
5V | 5V | -
3V3 | 3.3V | 3.3V
RST | Reset | RST
DHT22 :
Working PrincipleThe schematic diagram is shown as below.
DHT22 capacitive humidity sensing digital temperature and humidity module is one that contains the compound has been calibrated digital signal output of the temperature and humidity sensors. Application of a dedicated digital modules collection technology and the temperature and humidity sensing technology, to ensure that the product has high reliability and excellent long-term stability.
The sensor includes a capacitive sensor wet components and a high-precision temperature measurement devices, and connected with a high-performance 8-bit microcontroller. The product has excellent quality, fast response, strong anti-jamming capability, and high cost.
Standard single-bus interface, system integration quick and easy. Small size, low power consumption, signal transmission distance up to 20 meters, making it the best choice of all kinds of applications and even the most demanding applications.
DHT22 has higher precision and can replace the expensive imported SHT10 temperature and humidity sensor.
It can measure the environment temperature and humidity to meet the high demand.The product has high reliability and good stability.If it's used and combined with special sensor Arduino expansion board, it will be easily implemented the interactive effect which related to the temperature and humidity perception.
Caution: DHT22 digital temperature and humidity sensor is designed for analog sensor interfaces.The analog port will be used as the digital which will not occupy the original digital port of the Arduino.The lines of the sensor which can transform the analog function to digital that can be use on digital port.
Specifications- Supply voltage: 5V
- Output voltage: 0-3.3V
- Temperature range:-40-80℃ resolution0.1℃ error <±0.5℃
- Humidity range:0-100%RH resolution0.1%RH error±2%RH
- size: 38 x 20mm
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