Attiny Fairy lights USB phone charger

tl;dr

Last year I noticed that poundland were selling IOS and android phone chargers that had fairy lights wrapped around them. I thought this was a cool idea and bought some, I decided to upgrade mine because why not. Join me below to see what upgrades I made.

Hardware

  • Attiny85 SMD
  • 2N2222 SMD transistor
  • Weld USB male plug
  • IOS fairly light charging cable

Paracord

So after reading THIS article on making artisan USB cables I thought I would have a go and make myself some custom cables. My first upgrade to the cheap poundland charging cable was to cut off the molded male USB A plug and replace it with whats called a “weld” one. Not only do they look a lot nicer they allow us to then paracord the cable (follow this guild I wrote HERE) I used a Christmas themed paracord to really complete the look.

Adding smarts

Its all well and good having static lights wrapped around the charging cable but wouldn’t it be even cooler if the lights pulsed or flashed. It was while I was building my last project (Tiny glowstick) that I came up with the idea with putting a SMD attiny85 into the USB male port itself, I would need to 3d print a cover for it but that wasn’t an issues since I now have a 3d printer. I found some tiny SMD 2N2222 transistors to run the lights, All was left was to design a tiny PCB to tie it all together. I had had thought of just dead bug soldering it inside the USB plug but it would have been a nightmare. To fit it in I just soldered the normal 4 USB wires into the plug then placed the PCB over the top then using solid core wire bent down from the PCB to the VCC and GND USB wires, Then all you do it solder the fairy lights VCC and GND to the other end of the PCB.

When laying out the PCB I got the SMD transistor footprint messed up, Basically I didn’t check to see it the footprint matched my symbol so 2 of the pins were reversed. This wasn’t a problem because all I had to do was flip the transistor over and solder it on its back. I have since fixed the boards layout issues so the board files below will be ready to use without modification.

3D printing

This is a project that wouldn’t be possible without 3d printing. The case took quite a few iterations before getting it right. The hard part was trying to come up with away to stop the case sliding backwards and forwards when inserting the USB port. I went with added a small notch to the inside that went into a hole in the metal USB case.

I also added a notch to ether side of the case so the lid would have something to lock into, I then just super glued the 2 half’s of the case together

Files

https://github.com/facelessloser/tiny_usb_charger_board

Video

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