NTP synchronized desktop 7-segment clock

Features

1. NTP sunchronization using WiFi.
2. RTC backup - will show time from a high precision RTC if WiFi is not available.
3. Automatic display brightness control.
4. Automatic timezone data update from online TZDATA database.
5. Settings via WiFi AP mode and a web page.

Pictures

Bill of materials

Part	Price
ESP32, Generic DevKit V1	$8
Adafruit 1.2" 7-segment display	$18
DS3231SN RTC module	$18
Adafruit VEML7700 lux sensor	$5
Custom I2C and power hub board	$5
Jumper wires, Female-Female	$2
M3, M2.5 and M2 bolts	$5
3D printed plastic enclosure	$8
Tint film (ex. for cars)	$1
-------------------------------	-----
Total	$70

Building and running the device

1. Manufacture I2C/Power hub using files from cad/i2c_header_x5. Don't forget 3.2K pull-up resistors.
2. 3D print enclosure using files from cad/enclosure.
3. Apply tint film to the display module.
4. Assemble the device. Select appropriate screw diameter and length for each hole. Connect hub 5V to VIN in ESP32, ground to ground, 3.3V to 3.3V, SDA/SCL to appropriate ESP32 pins. Connect every component to the hub.
5. Install ESP-IDF v4.4 - https://github.com/espressif/esp-idf/tree/release/v4.4 .
6. Clone repository and init submodules recursively.
7. Copy main/secrets.h from main/secrets.h.example and set your own setting inside.
8. Using instructions from EPS-IDF, build and flash the firmware.

Changing settings after flashing firmware

1. To change settings after flash, connect the device to power and press 'SET' button on the bottom.
2. Device will create a WiFi AP with SSID looking like ntpclock-XXXXXXXX.
3. The password will be shown scrolling on display.
4. Connect to AP and open http://192.168.4.1 .