Big DIY clock based on LED filaments.
LEDclock project is a simple, yet very big and bright clock based on chinesium 3V LED filaments (designed to look like a incadescent bulb tungsten filament... from the distance, I guess).
- 24 hour clock,
- time setting via two buttons (one for minutes, one for hours),
- long press button to set time faster,
- blinking after power loss to indicate that the time is incorrect,
- RTC calibration with 1 ppm precision (+- 999 ppms),
- slow, gradual enabling/disabling changed screen segments (PWM),
- brightness setting,
- watchdog,
- calibration and brighness storage on the EEPROM.
To increment minutes press upper button, to increment hours press lower button. Long press for fast change Press both buttons long to change mode. Available modes:
- RTC calibration,
- brightness setting,
- normal operation (clock mode). After 5 seconds of buttons not being pressed display will return to clock mode.
Display: Cxxx for positive (making clock faster), Exxx for negative calibration. Press upper button to increase calibration value, lower button to decrease. Allows calibration from -999 to 999 ppm.
Display: b x. Press upper button to increase brightness, lower to decrease. Brightness levels from 0 to 8 are available.
That's great! I am providing everything you need to make one yourself.
Send gerber files to the PCB manufactuer of your choice. Make sure to get 28 milled slots done - it is essential, as LEDs are mounted on the bottom side and are viewed from the top side.
Please see the bom.csv file with all needed components. You can get LED filaments from here https://pl.aliexpress.com/item/4000478265055.html. Make sure to get 3V version!
This project uses pretty much only SMD elements, but all of them can be mounted using basic soldering iron.
Dot LEDs can interfere with the ISP interface (depending on the programmer)! Mount R12 and R13 resistors after downloading FW to the board.
Watch out for LED filaments polarisation. + side is marked by a small hole in the lead - solder this side to the "common" side (the side that is connected to the neighbour LEDs).
To build FW you need avr-gcc along with avr-libc. To download the FW to the MCU you need avrdude.
My suggestion is to use USBasp programmer and avrdude software tool. I've provided needed commands in Makefile.
First we need to set fuse byte to change default 1 MHz CPU clock to 8 MHz:
make fuse
then we can download FW:
make install
Done! The clock should now be ready to be used.
Housing is too big for most 3D printers to fit, so it was designed to be able to split into 3 parts. You need to split 30 mm on both sides. Three pieces can then be reattached by using 4 M4x25 (conical head) and 2 M3x50 screws. Many other screw lengths will do the trick. PCB is attached to the housing using 2 M3x8 screws.
LED filaments give huge brightness but poor constrast - filter is needed. Print 4 times filter.stl, use dark filament for best result, 0.2 mm layer height. Put them into slots on the top side and hold them in place with a little drops of superglue.
Screen without the filters:
Free for non-commercial use and educational purposes. See LICENSE.md for details.
If you like my project and would like to endorse me, you can donate any BTC amount to the address:
3EL4b7g72awqXzzVFQan2h2PmizMhSSYMX
