A LED tree that you can blow out

LED Tree - Finished - top view

Finished – top view

A few words of introduction: (maybe not a few, quite a lot actually 😀 )

You must be wondering why I’ve done this fancy and unusual project. The answer is pretty straightforward:  I wanted to make “one of a kind” gift for my friend. Just something you can’t buy in a store , you know what I mean :).

The whole project took me quite a lot of time, mainly because it took a looong time for the PCB,s to arrive from China.

The LED tree from the electronics side is almost 100% analog, you know capacitors transistors and other stuff like that. Because of that I think its safe to say that it is the most complicated blinking LED circuit in the whole world (probably the biggest overkill I’ve ever done 😀 ). But you know, certainly this tree wouldn’t be so fun to build if I’ve used a μC.

The whole tree consists of a 16 individual twisted copper wire branches with LED,s on its ends, each of these LED,s can be blown out separately. I’ve also added a nice fade in effect (LED,s turn on quite slowly after being blown out). But wait, there’s even more: I’ve implemented a simple game! If you blow out all LED,s before they light up again, the PCB’s will start glowing red indicating that you were fast enough :D. It’s not that simple to blow out them all at once as I thought it will be 😛 . If you want to try again, you can reset it with a button.

Anyway, down below in this short post I will show you how the whole thing was designed, how it looks and how it works:


Some photos of a finished tree

Mhhhmm it looks so goooood  😍  …… , just take a look at them:

LED Tree - Finished - top PCB 2

Finished – top PCB 2

LED Tree - Finished - side view 3

Finished – side view 3

LED Tree - Glowing LED,s

Glowing LED,s

LED Tree - Glowing LED,s - top view

Glowing LED,s – top view

LED Tree - Finished - bottom view

Finished – bottom view

LED Tree - Finished - side view

Finished – side view

LED Tree - Finished - side view 2

Finished – side view 2

LED Tree - Finished - top PCB

Finished – top PCB

LED Tree - Glowing LED,s - side view

Glowing LED,s – side view


Short video

Forgive me the poor quality of the vid. [ It has been recorded with a brick 😀 ] .


Schematics & how does it work

Schematic of each LED control block is relatively the same as in the LED you can blow out like a candle projectBut there are some important changes to it.

For example: I’ve used less components to build each LED control block ,there is a special voltage reference just to improve overall stability of the whole circuit , PSU was redesigned to reduce noise and voltage spikes (certainly we don’t want that, when working with analog signals), I’ve also added bypass caps in some places and more…..

To implement a simple game which I’ve described above, I needed to add some logic gates and one JK flip-flop. You can take a look at it down below:

LED Tree - "game block" schematic

“game block” schematic


PCB design

The whole PCB was designed in Autodesk Eagle software. It took me about one or two days to draw the schematic and design the PCB itself . I’m quite happy with this layout, all small components are tightly packed on the PCB. Because of that a small issue appeared: there were no free space left for the silkscreen. So I needed to put component designators quite far from them , it’s not practical but I haven’t found any other way to solve this problem.

The PCB doesn’t have to handle high current,voltages and frequencies, so I didn’t have to care about: copper thickness ,traces width and their shape, substrate type and other stuff like that.
The PCB has a diameter of 100 mm (max. size before manufacturing price starts to grow exponentially 😀 ).

I’ve ordered 5 of these from PCBway for 5$ + shipping. The overall quality is quite impressive for this price. The only thing I’ve noticed is that the silkscreen is slightly offset from the pads.

As I said before, most of the passive components are in 0603 package.

LED Tree - PCB render - top layer

PCB render – top layer

LED Tree - PCB render - bottom layer

PCB render – bottom layer

LED Tree - PCB parameters

PCB parameters

LED Tree - PCB render - vias & holes

PCB render – vias & holes


Soldering the PCB, adjustments and testing

I took advantage of the opportunity to learn soldering some small SMD components (0603 and smaller). As it turned out later, It was quite tricky. I’ve soldered everything by hand , because of that it took me almost a eternity to solder them all …

After putting everything together I just needed to adjust some potentiometers to make it work. It was a pretty straightforward process really nothing special.

LED Tree - Potentiometers adjustment

Potentiometers adjustment

LED Tree - Soldering components on a PCB 3

Soldering components on a PCB 3

LED Tree - Tests and minor adjustments

Tests and minor adjustments

LED Tree - Tests and minor adjustments 2

Tests and minor adjustments 2

LED Tree - Soldering components on a PCB 2

Soldering components on a PCB 2

LED Tree - Soldering components on a PCB

Soldering components on a PCB

LED Tree - Soldering components on a PCB 4

Soldering components on a PCB 4

LED Tree - Soldering components on a PCB 5

Soldering components on a PCB 5

LED Tree - Copper wire branches

Copper wire branches


3D printing some customized M3 standoffs

Really nothing special, I just love to look at my printer when its doing its work, it’s so addicting….

LED Tree - 3D printing parts

3D printing parts


Summary

I hope you liked it, maybe I’ve inspired you to make something creative.

As always, you can post comments down below↓↓ (If you have any questions feel free to ask):