Last year I decided to jazz up our family Christmas cards with LED power, inspired by this article. While I was totally happy with the cards I sent out, I was wanting something a bit more this year so I've decided to take it one step further and create Christmas ornaments for our family that will be sent with this year's Christmas cards.
I had a few criteria that drove my design for the ornament not to mention I had a very short timeframe so simplicity was important:
1. Have the same shape as a typical Christmas ornament (it is an ornament after all).
2. Lots of LEDs, folks in my family love LED blinky things.
3. Battery powered and last as long as possible on battery.
4. Hackable. I wanted the board to be easily hacked by family and friends that were so inclined.
5. Maximize the visual appearance of the front of the board (no through-hole components), I was also going to put a Christmas message on the front in silkscreen.
After a few hours piecing together the schematic, I was pretty happy with the reChristmasOrnamentsults. Ironically when I went to start the board design I ran into a simple but problematic issue of how to evenly place the LEDs on the round board, being the true geek that I am, I wrote a C# app which you can see in the ZIP file attached to this post. It gave me the x and y coordinates for each LED given the radius, origin and degree. Being late at night when I finally got around to laying out the board, this was a true life saver!
Once I had the LEDs placed, I decided to go back and add some blue and white LEDs on the neck of the board to enhance the "blinky" factor. Skip ahead 4 more hours and I had finished the board layout. I always give myself a day or two after the board is done before I come back to it and QA the layout, saves me tons of time staring at a problem and not seeing it! My QA found several issues and once resolved I sent it off to the boys over at BatchPCB.com for fabrication.
Fabrication typically takes three weeks or more but I was nicely surprised when my boards shipped after only 7 days and being the OCD type I am, I had to assembly one of the boards as soon as they came in the mail. It took me about 3 hours to assemble the first board, I was being overly cautious and deliberate in each solder and relearning how to use my hot air rework station. The total time for the first board included soldering up my homemade ATMega TQFP programming board which I used to burn the Arduino Uno boot loader onto the ATMega chips I had leftover from a previous project. I'll post about it in more detail later, I have a few minor tweaks to make to the design before I think I'll be totally happy with it, but it served me well for this project.
With the boot loader loaded, the final test would be attempting to load a sketch on it using my FTDI cable. To my total elation, it loaded the sketch without issue and my blinky utopia began! I was absolutely filled with joy when those LEDs started blinking away, who knew something so trivial could be so satisfying. I learned a lot with this project and I gained some important confidence in my design and layout skills which should serve me well with my next project.
As for battery life, I've adjusted some of the animations so that I could eliminate having all the LEDs on for extended periods of time and found that I was able to leave the ornament on constantly and the batteries died (the board actually froze) after about 40 hours. I thought about putting in a sleep mode after 6 hours of use or something but I think I'll pass and allow the user to just remember to shut them off, heck those inclined could do it themselves!
Well, I'm giving out the ornaments on Thursday (Thanksgiving) so that friends and family can enjoy them on their trees this holiday season, I sure do hope they enjoy them as much as I enjoyed building and designing them! Check out a video of them in action below!
I recently remodeled my office as I'll be working from home full-time starting in March, it's amazing what you can do with $1k dollars at Ikea! Anyhow, love my office setup, especially my desk but I had one nagging issue, I couldn't see the keys of my keyboard easily when the office was dark. My wife subltly suggested I get some sort of light to put underneath my desk to illuminate the keyboard. Ah, how I love my wife and her fantastic ideas...
Obviously, I wouldn't settle for some store bought device, I'm a self-declared "Maker" after all! After several days of tossing around ideas in my head, I decided it'd be super neato to have an RGB LED board under my desk and have it connected and powered by my computer. I'd then have some software sit in my system tray so I could control the board (colors and etc). Yeah, that's exactly what I needed!
So, yesterday I decided I'd set out to build it with only the parts I had on hand, I'm having a baby and thusly on a very restricted hobby budget!
Since I'd be etching the board myself, I knew I'd use through hole components to make life easier and I centered the project around an ATMega328 since I wanted to use serial communication with my PC and the quickest path was to use Arduino programming language (using a FTDI cable). I also wanted to utilize some 5mm common annode RGB leds I had on hand from a previous project but I wanted at least 5 to make sure I had good illumination on the keyboard and I wanted to use PWM to allow color mixing...well, a few 2907A transistors and a dozen or more resistors later I had a schematic I could be proud of.
The layout of the board was easy, I had a 3"x4" single sided copper photoetch board, so I laid all my components out to fit the whole board (I didn't want to cut it). I also learned the hard way that small traces are a pain in the butt when etching your own boards so I set my traces to 24mil, genrously large enough to not create issues during the etch. I didn't get any pictures of the board before it was mounted, sorry. You can always refer to the board image in the zip file attached to this post.
Once I had soldered all my components on the board, I threw in an ATMega328 micro that already had the Arduino bootloaded burned. Hooked up my FTDI cable and my test sketch worked flawlessly. Whew, nothing like going from concept to finished board with no testing to get the nerves going!
With the board testing out good, I set about coding up a C# app to control it. I had previously worked with serial comunications using C# and an Arduino which I talked about in this post so the C# code was really more about figuring out how to get a sys-tray app working as I wanted than worrying with the serial communications. I think it took me about 2 hours from start to finish to get things to a point I was happy with (nice and quick not nice and neat). I'm a developer by trade so I knew all along this would be the easiest part for me.
Well, a very quick project for me, one I'm quite proud of actually. As always I've attached high resolution pictures, eagle schematics, Arduino sketch and this time the Visual Studio solution in the zip below.
Drop me a note if you have any questions about this project, I think it's a fun and easy project for folks to test out thier etching and coding skillz!
Check out the videos below to see the software and board in action!