1.3" TFT Clock with "Morphing" Display

Description

This project is a tiny bedside clock built using a 1.3" TFT display paired with an Adafruit Itsy Bitsy M4 and the Adafruit high resolution clock time (DS3231).

My wife provided the design direction of the hour display and the minute hand. She chose a "morphing" design where the 12 rows for the hour digit each indicate a five minute section of the hour. As each five minutes of each hour elapses, one of the rows is replaced by the image of the subsequent hour. Thus, by a quick glance, you can detect about how much of the hour has been consumed.

Time flies, how did you spend it?

Details

Bill of Materials

M2 bolts - 10 mm (4 quantity)
M2 nuts (4 quantity)
3D printed case (2 pieces)
1.3” IPS TFT (generic version used here, 7789 chipset)

Adafruit Itsy Bitsy M4 Express (https://www.adafruit.com/product/3800)
Adafruit DS3231 breakout (https://www.adafruit.com/product/3013)
CR1220 Battery (https://www.adafruit.com/product/380)

Wiring Instructions

The following table shows the wiring instructions for the Itsy Bitsy, the TFT display and the DS3231 real-time clock breakout. The wiring color indicates the wire insulation color that is shown in the images.

Adafruit Itsy Bitsy M4	TFT Display	DS3231 Breakout	My wiring color
M0	SDA		yellow
SCK	SCL		blue
3V	VCC	VCC	red
GND	GND	GND	green
SCL		SCL	black
SDA		SDA	white
10	DC		white
11	RES		black
13	BLK (backlight - PWM signal)		yellow

Special notes on the software (Arduino)

Be sure to include the images.h file into your Arduino project.

The generic IPS TFT display I used has a ST7789 chip, and it required to use "SPI_MODE3" in the tft.init statement.

I control the backlight brightness by a PWM signal. I selected a value of 8 since this is a bedside clock. Also, you can change the minute hand to a different color. White can be very bright at full brightness (255).

I updated the software to includes the hooks for daylight savings time using the Timezone library (https://github.com/JChristensen/Timezone). Before compiling, update the Timezone rules for your location.

Also, I am including a short program to update the real-time clock to the current time. Run this to update the RTC before you load the final program. This short code allows you to update the real-time clock to UTC time by providing a few variables so you can create the correct time offsets.

3D Printing the case

The case is relatively easy to print. I printed the front standing upright, with support. I printed the back piece with the back lying flat on the print bed.

Files