Bilibili video link

Development notes

Program source code

8-MD-06INKM Screen Driver Notes

Using 8-MD-06INKM with built-in driver for VFD screen production, using STC8G1K17 for single-chip microcomputer. Two DCDC channels, M3406-ADJ 3.3V for single-chip microcomputer, clock chip, VFD screen filament, etc., SGM6601YTN5G/TR 5V boost to 24V for high-voltage input of VFD screen. The clock chip uses domestically produced SD3078, with an accuracy of ± 3.8ppm. The backup battery for timekeeping uses ML621-TZ1, which can maintain power-off timekeeping for about 8 months when fully charged. The breathing light uses SK6812 packaged in 1515.

Program download: Please understand the use of STC-ISP, frequency setting 24M.

Assembly: The VFD screen is fixed on the PCB with 3M double-sided tape, the rear panel single-pass copper column M2-5 + 3mm x4, the front panel double-pass copper column M2-7mm x4, M2 round head hexagonal bolt x8, and two cut 1.8mm thickness acrylic plates (cutting specification files are in the circuit engineering, front and rear panels, please export them to Taobao to cut)

Attached please kindly find the compiled .hex program text, as well as the purchase links for copper columns, screws, ML621-TZ1, SK6812, turtle touch buttons, and photosensitive resistors

Note: After completing the components and before downloading the program, be sure to check the welding situation and whether there is a short circuit. Light damage to the board can cause serious damage to the computer!

L1, C6, C7, and C8 must have sufficient pressure resistance!

ML621 batteries must be soldered with a soldering iron, and cannot be soldered by pasting two pins at once!

The buzzer cannot be cleaned with board washing water!

Update record:

2022-11-26: fix bug--turn off the breathing light after re-power will static green, on this basis to open the countdown will static red, exit countdown reminder animation is still static red

2022-11-29: the boost circuit control R3 1K, R4 10K changed to R3 10K, R4 left blank.

Dimensions and working parameters, etc.

Dimensions: 81mm * 23mm * 22mm (manual measurement may result in large errors)

Working temperature: -10~ 60 ℃

Working voltage: 5V

Working current: average 154mA, the instantaneous current of the buzzer is about 410mA, turn off the display standby 8mA

The power supply interface is a 6pin Typec port. Choose a 5V 1A power adapter or one that can output a larger current.

Please keep the RTC battery fully charged for at least 3 days after the first power-on

Do not touch with wet hands

Do not use the computer USB port to power the clock

Oxidation and blackening of copper columns is a normal phenomenon

Scroll time refresh

24-Hour time display

5-Level brightness adjustment or automatic brightness adjustment

Circular breathing light

Travel time error within 2 minutes per year (room temperature 25 ℃).

Rechargeable RTC battery, the battery can run for about 8 months when the clock runs out

Turn off display at night

Countdown