TEMP


The EchoXL is a custom designed 7 segment clock, using four 4" displays.
I purchased these displays from Sc Electronics in Guanghua Electronic Plaza, Taiwan.
They are labeled "LS4006SRWK" and the datasheet can be found here.
I selected the ESP32-C3 (WROOM-02-N4) MCU for its onboard Wi-Fi, USB programming, appropriate pincount and affordability.
The board uses a CH221K to negotiate 12V via USB-C PD.
The 12V USB power is fed into a pair of TLC5926 16 channel current control LED driver ICs.
A simple buck supply (AP63203) produces the 3.3V rail for the ESP32-C3 and the simple peripherals.
These peripherals being an LDR for ambient light brightness adjustment and a single user button.

The provided firmware is a polished, simple digital clock.
The clock will attempt to connect to a saved network on boot. If none is found, it will set the time to 12:00 and blink a status segment.
The user can then connect to an HTML captive portal GUI produced by the clock.
The user may enter the current time manually, or input a network SSID and Password.
The clock will attempt to connect to said network and use NTP to set the current time.
The clock saves network settings through reboot and will attempt to reconnect on boot. Failure to connect will restart the loop.

Additionally, the user may short-press the user button to cycle through four brightness modes:
Automatic, Low, Medium, High
The user may long-press the user button to switch between 12h and 24h time.
Holding the user button on startup will reset the network settings.

Known issues: