An array composed of ws2812b is used as the display module and sht30 is used as the temperature and humidity sensor. The mcu is the atmega328P of arduino.

Temperature and humidity LED alarm clock based on Arduino

This project is to make a simple temperature and humidity LED alarm clock, using Arduino atmega328P as the MCU, and using Tuya WBR3 to connect to the Internet of Things platform. Multiple WS2812B 2020s are used on the board as LED arrays to display time, temperature and humidity, countdown and other information. WBR3 can transmit data to Tuya IoT platform to realize data statistics and monitoring functions.

1. Basic functions

1. It has the function of displaying time and setting up to 120min countdown

2. Connect a temperature and humidity sensor to collect indoor temperature and humidity

3. Equipped with WS2812B array, which can display the current time/temperature and humidity/countdown status in real time

4. Connect to the Tuya IoT platform to realize intelligent remote timing and statistical temperature and humidity data

2. Device selection

Arduino 328P

We directly use 328P as MCU because it can be developed with Arduino and can work directly at 5V. It is more convenient to connect to 5V WS2812.

DS3221

RTC chip ensures that time information can still be displayed normally even after the network is disconnected. The MCU reads information through I2C.

CH340C

USB to serial port chip

WS2812B

Addressable LED. When connected in series, you only need to take a signal from one pin of the MCU to control the entire LED matrix.

SHT30

Temperature and humidity module. The MCU reads information through I2C.

2. PCB layout

1. Two panel design

The MCU module, IoT module, power module, RTC module, etc. are on the board and the LED matrix is ​​on another board to save costs (double-layer boards are cheaper) + help LED heat dissipation and increase lifespan

2. Copper pillars are also part of the circuit

The two boards are joined together by copper pillars at the four corners. In addition to serving as structural support, the copper pillars also play a circuit role in providing +5V, GND and LED display signals from the MCU motherboard to the LED board.