Brian Lough

PCB3 - The Christmas Tree shaped PCB

It's beginning to look a lot like a PCB

It is a PCB in the shape of a Christmas Tree with 12 charlie-plexed LEDs reverse mounted to shine through the board. The board is controlled by an Attiny 13 and is powered by a Cr2032 coin cell battery.

Available to buy on my Tindie store!


General Documentation

This is the documentation that I would have included in the package if you requested it. There are some basic solder tips and information about the different tree modes project page for some log entries about the project etc


Github - This is the code the tree ships with. Chips are all pre-programmed.

More detailed solder instructions

Coming soon to the link

LED orientation

For LED orientation here is a template where the LEDs are spread out pretty well, it only makes use of 4 of the 5 colours though (The white LED, which is a 6th colour, is for the star). It is mirrored so when you are soldering the LEDs on the back you can solder them as you see them here.

Micro USB Breakout

I honestly didn't expect anyone to order this, but basically anyone who could did!

First thing to say is however you work the Micro USB, never plug the mirco USB and a battery in at the same time!

For attaching it you have a couple of options, here is all the VCC and ground pin on the board marked, any of these can be used for the micro USB. Red is VCC and black is Ground

Battery clip slots:
These are the 3 larger pads at the base of the tree, the one above the 4 header pads and the two either side of them. These can be used but then you cant really use the battery, an OK choice if you definitely aren't running off battery or using the battery holder as a stand.

SAO header:
These are the 4 pads at the base of the tree. When looking from the front the top left is VCC and the bottom left is GND. These are a decent option but it might be hard to solder wire in there and get the battery clip on. If you used thin wire it should be possible though.

ISP pads:
If you aren't interested in reprogramming the boards you could use the ISP pads, the 6 squares above the battery slot on the back of the tree. Another negative about this one is that it's passed the switch (so is connected to the circuit regardless of the state of the switch

Bodge USB to Coin cell adapter:
I played around with the micro USB adapter a bit and came up with this bodge, and it actually works well! This would be my preferred option as it gives good flexibility

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Its just a single stripped wire bent back on itself on each side. The one on the top is connected to GND and the one on the bottom is connected to VCC. Make sure to insulate the pads in the middle with some tape or you will have a short!