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https://github.com/mignon-p/treeornament

A circuit board Christmas ornament, shaped like a tree, designed with KiCad.
https://github.com/mignon-p/treeornament

christmas kicad leds oshw

Last synced: 7 months ago
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A circuit board Christmas ornament, shaped like a tree, designed with KiCad.

Awesome Lists containing this project

README 

          
This repository contains the [KiCad][1] and [Gerber][2] files for a

PCB Christmas ornament shaped like a Christmas tree.



![photo of ornament](photo.jpg)



The little tree has candy canes on the silkscreen, ornaments made out

of exposed copper, and a trunk made out of exposed FR4.  The garland

is made out of resistors, and the lights are LEDs, powered by a micro

USB connector on the back.



You can hang the ornament on your tree by putting a string through the

hole at the top of the ornament.  Or, you can use it as a standalone

decoration, in which case the USB cable in the back acts as a sort of

"[kickstand](kickstand.jpg)" to hold the tree up.



This README should contain enough information to build the ornament.

However, if you want more detailed, step-by-step instructions with

pictures, I've also written

[an Instructable on how to build the ornament][17].



## Bill of Materials



* USB Micro B connector, qty 1.  Würth part number 614105150721.

  Digi-Key part number [732-5958-1-ND][3].



* 1/8 watt resistors, qty 14.  Make sure the length of the resistor is

  around 3.3-3.6 mm.  The minimum resistor value you should use is 150

  Ohms.  However, I found that to be too bright, so I eventually

  settled on 1k Ohm resistors.  Especially if you use different LEDs

  than I did, you should experiment to see what resistor value gives

  you a brightness that you like.  For 1k Ohm resistors: Stackpole

  part number CF18JT1K00.  Digi-Key part number [CF18JT1K00CT-ND][4].



* 3mm LEDs, qty 14.  Just about any 3mm LED should do, but I used

  color-changing LEDs to [add a bit of motion][13] to the ornament.

  When soldering the LEDs, make sure the short leg of the LED goes

  into the square pad, and the long leg of the LED goes into the round

  pad.  For color-changing LEDs: SparkFun part number [COM-11448][5].

  Digi-Key part number [1568-1196-ND][6].



* Optional: 3.3µF 0805 ceramic capacitor, qty 3.  These probably

  aren't essential, but since decoupling capacitors are considered to

  be a good idea, I added pads for three capacitors on the back of the

  board.  (Though if you're using ordinary LEDs, you really don't need

  them, since the current will be constant.  I only added them because

  I'm using color-change LEDs, which probably use PWM to fade through

  the colors.)  Unlike all the other components, these are

  surface-mount, so they're a little trickier to solder.  It helps if

  you have a second person to hold the capacitor in place with

  tweezers, though it's [possible for one person to do it][22].

  Samsung part number CL21A335KPFNNNG.  Digi-Key part number

  [1276-6461-1-ND][7].



* Optional: string to hang the ornament.  Just about any string should

  do.  I used [Hemptique red cord][8].



And, of course, you'll also need a USB charger and Micro B USB cable

to power the ornament.



## Circuit board



Most fabs should work fine, although you'll probably want a fab that

offers green soldermask.  (That rules out OSH Park, unless you want

purple trees!)  I went with [EasyEDA][9] because they are inexpensive

and offer green soldermask.  (However, it appears that EasyEDA is

spinning off their circuit board manufacturing to the site

[JLCPCB][18].)



I went with a PCB thickness of 1.0mm, because that's what

[the datasheet for the USB connector][10] recommends.  (With a thicker

PCB, the pins of the USB connector won't protrude all the way through

the board.)  I chose the more expensive [ENIG][11] finish, because I

thought that would look better on the exposed-copper ornaments.



If you're not making any changes to the board, all you need to do is

zip up the files in the `gerber` directory, and upload the zipfile to

EasyEDA.  After uploading the zipfile, these are the options I chose

on the EasyEDA site:



![screenshot of options](easyeda.png)



Note that in the KiCad files and Gerber files, the "front" of the

board is actually the back, and vice-versa.  This is because EasyEDA

adds a customer ID number to the front of the board, but I wanted the

number to be on the actual back of the board, where it doesn't disrupt

the esthetics of the ornament.



I recommend ordering more boards than you need, because some of the

boards will have cosmetic defects.  (They still work fine

electrically, but just don't make an ornament that looks as nice.)  In

particular, the FR4 appears to have some red writing on it in places,

so every now and then that will show up in the trunk of a tree.



Another way to solve the problem of the red writing on the FR4 is to

paint the trunk.  (e. g. with flat brown [Testors enamel paint][16])



## License



This design is licensed under the

[Creative Commons Attribution-ShareAlike 4.0 International license][12].



Some of the footprints in `myLibrary.pretty` are based on footprints

in the [KiCad library][14], which is licensed under the

[KiCad library license][15] (which is now also CC-BY-SA-4.0, with an

exception).



## Other circuit board trees



I'm not the only one to have had this idea.  Here are some other folks

who have made tree-shaped Christmas ornaments out of circuit boards:



* [CyrilSneer][19]

* [platisd][20]

* [Circtistic][21]



However, I feel that my version has some advantages:



* More LEDs - My version has 14 LEDs.

* "Cleaner" front - Mine has all the circuit traces on the back, so

  the front is more esthetically pleasing.

* USB Powered - Mine uses a USB charger instead of a battery, so you

  can plug it in with the rest of the lights on your tree.



[1]: http://kicad.org/

[2]: https://en.wikipedia.org/wiki/Gerber_format

[3]: https://www.digikey.com/products/en?keywords=732-5958-1-ND

[4]: https://www.digikey.com/products/en?keywords=CF18JT1K00CT-ND

[5]: https://www.sparkfun.com/products/11448

[6]: https://www.digikey.com/products/en?keywords=1568-1196-ND

[7]: https://www.digikey.com/products/en?keywords=1276-6461-1-ND

[8]: https://smile.amazon.com/gp/product/B007IT72JS/

[9]: https://easyeda.com/order

[10]: http://katalog.we-online.de/em/datasheet/614105150721.pdf

[11]: https://en.wikipedia.org/wiki/Electroless_nickel_immersion_gold

[12]: https://creativecommons.org/licenses/by-sa/4.0/

[13]: https://youtu.be/PZnlEJhb-sY

[14]: https://github.com/KiCad/kicad-footprints

[15]: https://forum.kicad.info/t/kicad-library-licensing/7856

[16]: https://www.testors.com/product-catalog/testors-brands/testors/enamel-paint/enamel-paints

[17]: http://www.instructables.com/id/LED-Circuit-Board-Christmas-Tree-Ornament/

[18]: https://jlcpcb.com/quote

[19]: https://forum.kicad.info/t/christmas-ornaments-designed-with-kicad/8674/2

[20]: https://www.hackster.io/platisd/a-christmas-tree-pcb-ornament-8bc03b

[21]: http://circtistic.com/

[22]: https://youtu.be/cBgmY16goX0