"Saiko" IoTomatic Watch with ESP32 and Round LCD

"Saiko(u)" (さいこう) is an ESP32-based NTP clock using a GC9A01A round TFT LCD (240x240 pixels).

The analog dial design is drawn mostly in real time by code and is based on/inspired by the Seiko 5 Sports SRPK33K1 38mm diver watch, with the second hand moves 6 times a second as in the 4R36 mechanical movement. The date and day window (with blue color for SAT and red for SUN) do not rotate like the real movement though.

The project is not meant for commerical use. You can read more about the more detailed story on my Hackster.io project page.

Wiring

ESP32	GC9A01A
GND	GND
3.3V	VCC
18 (SCK)	SCL
23 (MOSI)	SDA
22	RES (RST)
21	DC
5	CS
3.3V	BLK (backlight)

Libraries

• Arduino NTPClient
• Adafruit GFX Library
• Adafruit GC9A01A Library

Note: by default the NTP client will update time every 20 minutes and will check/force update every hour.

However, the NTPClient may cause several-second blocking delays during the updates (which makes the watch temporarily stopped moving) due to internet or NTP server issues. There is currently no good solution to get around this but to change a better NTP server and/or a better WiFi environment depending on where you are.

Clock Setup

WiFi, NTP and Hour Offset

In the script

1. Change the SECRET_SSID and SECRET_PASS to your WiFi ssid/password in secret.h.

2. Modify NTP_SERVER and NTP_HOUR_OFFSET to your preferred NTP server and time zone adjustment.

Demo Mode

If DEMO_MODE in the script is set to true, the watch will not connect to WiFi/NTP and displays a fixed time (10:08:42 SUN 31th).

Benchmark

If BENCHMARK in the script is set to true, it will calculate and print the time of each cycle for drawing the dial in serial.

Additional Notes

• Most specs and color on the dial can actually be adjusted, for example:
  • LOGO_NAME is the name shown on the top half of watch, and DESCRIPTION is the smaller text on the lower half.
  • SECOND_HAND_VIBRATION defines the the second hand vibrations (6 = 3 Hz). The code automatically calculates the drawing cycle time and the second hand moving angle. From my own test each drawing cycle only took 37 ms - so in theory the vibration can be set to as high as 27 (= 13.5 Hz). However due to the drawing limitation, the second hand may not appear moving that much.
• The script utilizes an offscreen canvas (a buffer) to update the screen smoothly. However, it appears that the buffer cannot be as large as the screen itself without causing memory issues. This is why I chose a diver style since the outer bezel ring can be drawn only once, and I only need to update the inner dial afterwards.
• The script uses a few Adafruit GFX fonts. The complete list can be found here.
• The ESP32 is clocked at 80 MHz since we don't really need full speed to run this script, which helps to reduce the heat as well.
• The parts of the hour and minute hands are labeled by alphabet codes, since I do not know how to name them: