Very simple WiFi clock based on ESP8266 and (TM1637 or MAX7219)

Clock BIM

• Minimum details. 3 modules and 7 SMD components.
• The clock keep good time with Internet access. Thanks to synchronization with NTP server.
• Automatic daylight saving time only if needed.
• Decreased display brightness in night mode.
• Ability to set the time and brightness of night and day mode.
• Ability to connect 1 or 2 displays at once and choose what to show where.
• Display the temperature, humidity and pressure from wired sensors, from thingspeak.com and a weather forecast website.
• Sending data to thingspeak.com.
• Ability of correction of readings of wired sensors.
• Remote access to the settings of the clock, via web-interface.
• Simple and understandable even to an unprepared person settings.
• Ability to update the firmware over the air.

Schematics diagram

U1 is the heart of the clock this is Wemos D1 mini module, it is a module on an ESP8266 chip with all the necessary environment besides a USB -> UART converter and a 3.3V converter are built into this module.

The U3 display is a 0.5-inch 7-segment LED display module with an integrated TM1637 display control chip. Of course you can use the display and a smaller or bigger size but the board is made for this size. You can also use such a display with 6 digits, then seconds will be displayed. You can also apply a 6 or 8 digits display at MAX7219.

The U2 clock module on the DS3231 chip is needed to support the clock in the event of the loss of the Internet. This module can be not installed if you have a stable Internet. Firmware will determine for itself whether the clock module is installed or not.

Resistors R1 and R2 are only needed if you use a TM1637 display. The diode D1 is used to protect the pins of ESP8266 from overload. You can replace it with a jumper but it is unsafe. Filtering capacitors C1-C4 can be not installed but then possibly unstable clock's work, freezes, malfunctions. The buttons S1 and S2 are needed accordingly for resetting and entering the clock into the settings mode. Buttons as you may have guessed can also not be installed. J1 connector is used to connect the temperature, humidity and pressure sensors. Sensors should be located at a distance of at least 10 cm from the clock since the clock in operation is slightly warm and the sensors are very sensitive. If you don’t need temperature, humidity and/or pressure indications then you can not install the sensors respectively J1 connector will not be needed either.

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The clock supports the following sensors: BME280, BMP180, SHT21 (HTU21D), DHT22 and DS18B20. You can connect one or all the sensors together. In the settings you can choose which sensor where and when to display. The sensors are connected to connector J1, the pin assignment is shown in the schematics diagram.

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You can power the clock by any charger from the mobile phone with a voltage of 5V rated for a current of at least 0.5A with a micro USB connector.

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After assembly and flashing the clock needs to be set up. When you first turn on the clock themselves enter the settings mode. In the future, you can go to the clock settings by using the clock's ip address. Connect your laptop or smartphone to the network Clock password is 1234567890 and in the browser go to http://192.168.4.1 address. The default username is admin the password is 1111.