Xmas tree star topper

Christmas is nearly here and its time to get out and decorate the tree and what is a Christmas tree without a tree topper show stopper.

Video

Origin

This build is based on a Christmas Star project by Irina Ogienko.

In the comment section for this project, a user called dimmel published a set of printed circuit boards that were in the shape of a star. It also allowed the final unit to sit on top of a christmas tree.

Schematic

The project is built around a ATtiny2313 microprocessor. It uses a 74LS145 3 line to 8 line decoder/driver to reduce the number of I/O pins required.

PCB

The PCB layouts have been designed by dimmel using the Sprint Layout software. Since I was making my own boards, I used the Sprint software to print the PCB patterns directly onto the toner paper and used the toner method to make the boards. The Star PCB is double-sided while the Control PCB cab be single-sided.

Assembly

Start by assembling the Star PCB. Ensure you correctly orientate each LED. Solder the legs to both sides of the PCB if your board doesn't have through-hole plating.

The Control PCB should be straightforward to assemble. I used IC sockets and programmed the ATtiny2313 using my AVR ISP Programmer V2 before inserting it.

Mounting the control PCB

A plastic hollow cylinder with an inside diameter that fits your Xmas tree is joined to the Star PCB using double sided tape.

The control PCB uses nylon spacers to position the control board over the cylinder. I glued the spacers to the Star PCB.

I used pin headers to wire the two PCBs but that is optional. You can also just directly solder the wires on the PCBs.

Software

I used avrdude to upload the hex file to the ATtiny2313 cpu using my AVR ISP Programmer V2 programmer.

Conclusions

Merry Xmas and a Happy New Year to all 🎄🎅