[Tuya Smart] Cat Temperature and Humidity Sensor

Introduction:

        First of all, we would like to thank Tuya and Lichuang for their support and sponsorship, providing us with this opportunity and platform to improve our skills.

        Mao temperature and humidity sensing module based on Tuya WB3S low-power module, Mega328P-AU and SHT30 temperature and humidity sensor.

        Both the Tuya APP and the OLED screen can check the current ambient temperature and humidity, which is convenient and fast.

        It is powered by batteries and can be moved anywhere at any time. It supports charging with a 5V mobile phone charger. Both the APP and the screen will display the current battery level to prevent the device from running out of power.

        The module design is in the Lucky Cat style, which is beautiful and maximal. . .

        PS: With the later version of the program, it can be expanded into a cat feeder with temperature and humidity display (reminder of insufficient remaining food, cat food can be fed regularly and quantitatively, and there will be water when the cat comes)

        Using the 3.3V power supply method, the communication peripheral circuit between the Tuya module and the main control is extremely simple. Pressing the button will perform intelligent network distribution, and the Tuya APP can be added directly, which is convenient and fast.

        When configuring the network, the LED indicator light will flash on and off. After connecting to WiFi, the LED will flash on and off. When fully connected to Tuya Cloud, the LED will go out and the WiFi icon will be displayed on the screen.

Screen scheme :

       It uses a 0.96" 12864 monochrome OLED, which is enough to display device information.

Temperature and humidity are refreshed        every 10 seconds , and battery power is detected every 30 seconds .

       When both WiFi and Tuya Cloud are connected, the WiFi icon will be displayed. If not connected, an X will be displayed.

       When the battery power is above 30% , the battery icon is a full solid icon.

       When the battery power is below 30% , the battery icon is a hollow icon for low power. And the fully charged icon flashes alternately every 1 second .

Temperature and humidity sensor :

       Using SHT30-DIS-B temperature and humidity sensor, I2C communication method, and ready-made libraries, the temperature and humidity data of the sensor can be read very well.

       The collection accuracy can meet the needs of IoT devices.

    Peninsula typesetting can avoid the impact of heat generated by components on the PCB on the temperature and humidity sensor.

Power supply plan :

       Due to the use of XC6210bB332MR linear voltage regulator, the voltage drop is only 75mV/100mA , the maximum current is 900mA , and the peripheral circuit is simple.

       It can be powered directly by the battery, eliminating the power loss of boosting and then lowering the voltage. It can fully meet the power supply needs of the circuit.

Battery testing solution :

        Through the combination of transistors and P-MOS, the voltage dividing resistors R11 and R12 can be avoided from consuming battery power anytime and anywhere.

        Only when the power needs to be detected (that is, the power is detected regularly), the MOS is turned on through the BV signal, and then the battery is detected.

Program flash :

       The SPI6Pin interface is retained and can be flashed through the USBtoASP tool.

       The specific program is on GitHub (click me)  . You can also download Hex in the attachment of this page and flash it directly.

       When flashing in, you should pay attention to the following two points (device type, fuse position):

APP to check temperature, humidity and battery:

OLED screen viewing:

Physical PCB diagram:

Battery loading, direct welding and pasting:

Use the video (breathe with your mouth, don’t laugh, hahahahahahaha):

I don’t know how to upload a video. Then it's not good. Slightly, stick out your tongue