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Specs and configuration

Wherever I go, I’m asked why I chose DHT12, and why I came to write the library for this small sensor, today I’ll try to give an answer.

Sensors

Here the specification of sensor tested

BMP280

Temperature pressure sensor

bmp280

You can buy here

Specs

Low cost

1.71 to 3.6V power and I/O

2.74μA typical current, 0.1 μA in sleep mode

Good for 300 to 1100 hPa (equiv. to +9000…-500 m above/below sea level) ±0.12 hPa, equiv. to ±1 m

Good for -40-85°C temperature readings ±2°C accuracy

Average measurement time 5.5 msec

Temperature precision: 2 decimal

Digital interfaces: I²C (up to 3.4 MHz) SPI (3 and 4 wire, up to 10 MHz)

DHT11

Temperature humidity sensor

DHT11

You can buy here

Ultra low cost

3 to 5V power and I/O

2.5mA max current use during conversion (while requesting data)

Good for 20-80% humidity readings with 5% accuracy

Good for 0-50°C temperature readings ±2°C accuracy

No more than 1 Hz sampling rate (once every second)

Body size 15.5mm x 12mm x 5.5mm

Temperature precision: 2 decimal

4 pins with 0.1″ spacing

Unique 1-Wire® Interface Requires Only One Port Pin for Communication

DHT22

Temperature humidity sensor

DHT22

You can buy here

Low cost

3 to 5V power and I/O

2.5mA max current use during conversion (while requesting data)

Good for 0-100% humidity readings with 2-5% accuracy

Good for -40 to 80°C temperature readings ±0.5°C accuracy

No more than 0.5 Hz sampling rate (once every 2 seconds)

Body size 15.1mm x 25mm x 7.7mm

Temperature precision: 1 decimal

4 pins with 0.1″ spacing

Unique 1-Wire® Interface Requires Only One Port Pin for Communication

DHT12

Temperature humidity sensor

DHT12

You can buy here

Ultra low cost

2.7 to 5.5v power and I/O.

power and I/O. Operational Current: 1mA. Standby Current: 60µA.

Good for 20-95% humidity readings with 5% accuracy

Good for -20 to 60°C temperature readings ±0.5°C accuracy

1 Hz sampling rate (once every second)

Body size 7mm x 12mm x 5.5mm (W x L x H)

Temperature precision: 2 decimal

4 pins with 0.1″ spacing (VDD SDA GND SCL)

Unique 1-Wire® Interface Requires Only One Port Pin for Communication or I2C

4 Pinouts VDD SDA GND SCL.



Dallas Temperature ds18b20

Programmable precision temperature sensor



Dallas temperature ds18b20

You can buy here

Low cost

Waterproof version

Operating voltage: 3.0V a 5.5V

Operational Current: 1-1.5mA. Standby Current: 750-1000µA.

Good for -10 to 85°C temperature readings ±0.5°C accuracy

1 Hz sampling rate (less than 750ms)

Temperature precision: 0-2 decimal

Unique 1-Wire® Interface Requires Only One Port Pin for Communication

Thermistor

Temperature analog sensor (MF58-103 3950 B)

Thermistor MF58

You can buy here

Pratically 0 costs

Operating voltage n.d., It’s a resistence.

Good for -45 ~+250 (this type of thermistor have quite big range about ±0.5°C accuracy

Operating current: (<50mW) at 5v 25µA

Analog read It’s immediately

Temperature precision depends on analog sampling rate.

Unique analog wire.

Thanks

In the next part I show the library and how to use the sensors in the Arduino IDE.