Humidity Meter Using OLED Display – Arduino Compatible

Rajkumar Sharma
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SKU: EL110683
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This is an easy to build, very compact, and low profile Arduino compatible platform to build a humidity meter/Gauge using a 0.96Inch OLED display. The project consists of Atmega328 microcontroller, 0.96Inch OLED display, 3.3V regulator, and HIH5030 analog humidity sensor from Honeywell. The HIH5030 sensor provides an analog voltage output, the analog voltage is near linear voltage output vs %RH, the sensor output is connected to A0 (Arduino-ADC pin 0) of the ATmega328 microcontroller. The sensor output is 0.25V to 2.5V vs 0 to 100% RH. Connector CN2 is provided for boot-loader flashing and Arduino programming. Use Pin 4 GND and Pin5 VCC to power the project.

HIH5030 Humidity Sensor

The HIH5030 Low Voltage Humidity Sensors operate down to 2.7 Vdc, often ideal in battery-powered systems where the supply is a nominal 3 Vdc. The HIH5030 complements the existing line of 5 Vdc SMD (Surface Mount Device) humidity sensors. The HIH-5030 Humidity Sensors are designed specifically for high volume OEM (Original Equipment Manufacturer) users. Direct input to a controller or other device is made possible by this sensor near linear voltage output. With a typical current draw of only 200uA, the HIH-5030 is ideally suited for many low drains, battery-operated systems. Tight sensor interchangeability reduces or eliminates OEM production calibration costs.

Arduino Code

This is Arduino compatible project, a new Atmega328 microcontroller requires flashing the boot-loader and then program the Arduino code. Follow the link below to learn the programming process. Example code is provided as a download to test the project, this code is not accurate required proper calibration and mapping.

From Arduino to a Microcontroller on a Breadboard: https://www.arduino.cc/en/Tutorial/BuiltInExamples/ArduinoToBreadboard

Voltage vs Humidity Diagram

Applications

Industrial Air compressors
Battery-powered systems
Drying equipment HVAC (includes air conditioning, air movement, thermostats, humidifiers, de-humidifiers, humidistats, enthalpy sensing)
Office automation equipment
Process equipment Refrigeration (includes bulk and transport systems)
Telecommunications cabinets
Weather stations and meteorology equipment
Medical Hospital air compressors
Infant incubators
Microenvironments
Sleep apnea equipment
Treadmill stress monitoring equipment

Features

Supply 5V DC @ 10mA
0.96″ OLED display
Low power humidity sensor
Onboard voltage regulator
Programming header
PCB dimensions: 28.42 x 27.31 mm

Schematic

Parts List

NO.	QNTY.	REF.	DESC.	MANUFACTURER	SUPPLIER	SUPPLIER PART NO
1	1	CN1	4 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5317-ND
2	1	CN2	8 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5321-ND
3	1	C1	10uF/16V SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
4	3	C2,C3,C7	0.1uF/50V SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
5	3	C4,C5,C6	SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
6	1	R1	10K 5% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
7	1	R2	100E 5% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
8	1	R3	1M 5% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
9	1	U1	ATMEGA328TQPF-32	MICROCHIP	DIGIKEY	ATMEGA328PB-AURCT-ND
10	1	U2	HIH-5030-001	HONEYWELL	DIGIKEY	480-3294-1-ND
11	1	U3	LM1117-3.3V	ON SEMI	DIGIKEY	488-LM1117MPX-33NOPBCT-ND
12	1	X1	16Mhz	ECS INC	DIGIKEY	X1103-ND