This video presents a detailed teardown and comparison of two small, USB-C powered digital clock modules, both featuring four-digit, seven-segment displays. While outwardly similar and sharing identical PCB layouts and common components like the ESP8266 microcontroller and TM1650 LED driver, their core timekeeping mechanisms differ significantly. One variant functions as a standalone real-time clock (RTC) using an Epson RX8025 chip with battery backup and manual setting, while the other is a Wi-Fi enabled clock that synchronizes time from an NTP server. The video demonstrates troubleshooting the Wi-Fi clock's initial failure to display correct time, resolving it by reconfiguring its NTP server via a web interface. The teardown also reveals component details, functionality (like 8-level brightness control), and thermal observations, noting the ESP8266 runs warmer when its Wi-Fi functionality is active.
Two Digital Clocks: A Teardown and Comparison
0:00 Initial Unboxing & Power-up: The video introduces two 4-digit, 7-segment display clocks, powered via USB Type-C. Upon initial power-up, one clock (Wi-Fi version) displays "0" indicating a loss of time, while the other (RTC version) shows a time close to the current local time.
2:21 Identical PCB Layouts: Both clocks share identical circuit board designs, featuring an ESP8266 microcontroller, a crystal oscillator, and a memory chip.
RTC Version: Uses an R 8025 (identified as Epson RX8025) real-time clock chip, which is kept alive by a battery for time retention. The ESP8266 in this version is solely used as a microcontroller, not utilizing its Wi-Fi capabilities.
Wi-Fi Version: Relies on the ESP8266's Wi-Fi connectivity to obtain time from an NTP (Network Time Protocol) server. It includes a 4k-bit SPI EEPROM to store configuration settings like the NTP server IP address.
5:59 Shared LED Driver & Brightness Control: Both clocks use a TM1650 LED driver chip, which also handles keyboard scanning for the two setup buttons. This chip provides an 8-level brightness control for the display, a feature demonstrated on both clocks.
11:15 Troubleshooting Wi-Fi Sync: The Wi-Fi clock's failure to sync was resolved by accessing its web configuration interface (192.168.4.1 via a specific Wi-Fi access point name) and changing the NTP server address from a default Chinese server to time.apple.com.
13:37 Configurable Settings: The web interface for the Wi-Fi clock allows configuration of summertime adjustment, brightness level, time zone (+/- 12 hours), and 12/24-hour display format. The RTC version offers similar adjustments via its physical buttons, though not automatic summertime.
16:36 Thermal Observations: The ESP8266 in the Wi-Fi version runs noticeably warm due to its active Wi-Fi functionality. In contrast, the RTC version, which does not use Wi-Fi, remains cooler.
17:02 Availability: Links to both clock modules on AliExpress will be provided in the video description.