IoT clock

** Function **

An IoT clock with a digital tube as the display. It can display time, date, temperature and humidity and other information; it can automatically adjust the time through the Tuya WiFi module; it can monitor the temperature, humidity and brightness in real time through the mobile app. Functions such as temperature scale switching, brightness unit switching, time system switching, backlight adjustment and other functions can also be performed.

hardware

1. Main control MCU IAP15W4K58S4 LQFP48 (or STC15W4K58S4 LQFP48)

2. WIFI module Tuya WBR3D WiFi dual-band module overview: used to report temperature and humidity, light intensity, backlight brightness, temperature scale switching, time system, brightness unit and other information

3. Display overview of 0.8-inch 14-pin four-digit clock digital tube: used to display time, date, temperature and humidity and other information. 0.8-inch digital tube, clearly display data

4. Power management SP4522B synchronous charging and discharging mobile power supply SOC Overview: SP4522B is a single-chip solution for synchronous switching charging and synchronous boosting specially designed for mobile power supplies. It integrates a synchronous switching charging module and a synchronous boosting and discharging management module. , power detection and LED indication module, protection module. SP4522B has built-in charging and discharging power MOS, the charging current is 2.1A, and the synchronous boost output current is up to 2.4A. D1-D4 are battery indicator lights. Turn on the power switch or press K4 to indicate the battery level. The battery is charged through the USB interface or through the reserved 5V charging interface.

5. Voltage stabilizing circuit uses two HX6211A332MR chips to stabilize the 5V voltage output by SP4522B at 3.3V, which supplies power to the MCU and WiFi module respectively, providing a more stable voltage.

6. Temperature and humidity sensor uses SHT30 sensor. Overview: SHT30 is a new generation successor to the SHT2x series of temperature and humidity sensors. It is an entry-level version in the SHT3x series. It further improves product reliability and accuracy specifications, such as enhanced signal processing and an alarm mode with programmable temperature and humidity limits, and up to 1 MHz communication speed. SHT30 measurement data has been factory corrected, linearized and temperature compensated, and has temperature and humidity alarm output and software and hardware reset functions. The sensor's humidity measurement range is 0-100%RH, and the temperature measurement range is -40-125℃. I2C interface, optional I2C address, wide operating voltage range (2.15V to 5.5V).

7. Clock chip DS1302 Overview: DS1302 trickle charge clock chip, this is a chip that can carry a backup battery. When the battery is put in, even if the power is turned off, its time is still running. It contains a real-time clock/calendar and 31 bytes of static RAM, which communicates with the microcontroller through a simple serial interface. The real-time clock/calendar circuit provides seconds, minutes, hours, day, date, month, and year information. The number of days in each month and the number of days in leap years can be automatically adjusted. The clock operation can be determined by AM/PM instructions to adopt 24 or 12 hour format. DS1302 can simply communicate with the microcontroller in a synchronous serial manner, using only three port lines: 1 RES reset; 2 I/O data lines; 3 SCLK serial clock.

8. Overview of the light intensity sensor GY302 module: I bought this before and never used it. I just used it this time. High precision and small size. Adjust the brightness of the digital tube backlight by detecting light intensity.

9. Buzzer MLT-5030 Overview: Mini package, no edge buzzer, can be used to play music and alarm clock reminder.

10. Buttons Overview as shown in the figure: 4 buttons in total. K1+K2 enters the AP distribution network mode, and K1+K3 enters the SMART network distribution mode; press K2 or K3 individually to switch the display content of the digital tube; press K4 to display the power.

11. There are 3 LED indicators respectively, used to display working information overview: LED0 (red): WiFi module power supply indicator; LED1 (green): AP network distribution indicator LED2 (yellow): SMART network distribution indicator Lights When all three lights are on, the clock is in normal working condition and connected to the network.

12. Download circuit: A download interface is reserved, and the program can be burned through the USB to TTL module.

13. Shell: The shell printed on Taobao is very precise and the size is just right. You can print white PCB and omit the upper shell directly.

Modification 1. The design of the battery indicator light was reversed at first, which has been corrected. 2. Mark the positive and negative signs on the 5V input on the front of the PCB. 3. Changed the sht30 and buzzer to the front. 4. Changed the battery wiring to a soldering pad.