Hardware setup

Hardware setup

List of parts

Hot Air Soldering Gun

USB TTL adapter
NodeMCU or Wemos D1 Mini
AMS iAQ Core-C or CJMCU AMS iAQ Core-C board
DHT22 or AM2302
Jumper cables

Connections for v2.x.x

• The iAQ sensor using I2C bus, SDA and SCL pins must be pulled up via 4.7K (or 10K) resistors from 3.3V according to iAQ Core C's datasheet! See schematic below!

• I2C bus pins for IAQ sensor on ESP12E/F boards are GPIO5 - SCL and GPIO4 - SDA. If you are using Wemos D1 mini, I2C pins are SCL - D1 and SDA - D2!

• I2C bus pins for SHT3X sensor and OLED screen on ESP12E/F boards are GPIO14 - SCL and GPIO13 - SDA. If you are using Wemos D1 mini, I2C pins are SCL - D5 and SDA - D7!

• This sensor also has an option for resetting to factory default. Long pressing for 10 seconds a button connected to GPIO0 and GND will reset the sensor!

Connections for v1.x.x

• The sensor using I2C bus, SDA and SCL pins must be pulled up via 10K resistors from 3.3V according to iAQ Core C's datasheet! See schematic below!

• I2C bus pins on ESP12E/F boards are GPIO5 - SCL and GPIO4 - SDA. If you are using Wemos D1 mini, I2C pins are SCL - D1 and SDA - D2!

• This sensor also has an option for resetting to factory default. Long pressing for 10 seconds a button connected to GPIO0 and GND will reset the sensor!

• DHT22 sensor's data pin is connected to GPIO12 (Wemos D6) via 4.7K pullup resistor from 3.3V!

Schematic

Custom PCB design

I've designed a simple PCB for a 3D printable case. The design isn't the smallest one, but for reason: ESP8266 may heat up enough for distracting the DHT22's temperature measurement!

You can download the PCB Gerber files from here.

Prefix	Value	Package
R1	10K Ω	SMD 0805
R2	10K Ω	SMD 0805
R3	4.7K Ω	SMD 0805
R4	10K Ω	SMD 0805
R5	10K Ω	SMD 0805
C1	100nF	SMD 0805
C2	10uF	SMD 0805
C3	10uF	SMD 0805
C4	100nF	SMD 0805
C5	100nF	SMD 0805
D1	SS14	SOD123
U1	AMS1117-3.3	SOT223
Reset	Tactile 90 degree button	SMD 3x6x3.5mm
Serial	2.54mm 4P header	(optional)
H1	5V power	old microUSB female cable

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