Even though this build is relatively simple, I faced a few problems while building:
- The dimensions of the circles are very important. As I did not have access to a laser cutter, the circles have been cut by hand (not by me) and I faced problems while fixing the LED strip and the glass. I had given the dimensions to the carpenter in mm - but carpenter was used to inches and hence there was a slight rounding off in the dimensions. The center circle where the LED strip has to be stuck HAS to have a circumference of exactly 1000mm for the LED strip to fit correctly. The carpenter had made a larger circle and I had to pad the circumference with double sided tape. The outer circles where the mirror and glass had to be installed had the opposite problem - the glass simply did not fit. So I had to manually file the plywood to make the glass fit. My suggestion here would be to get the glass cut first and take it with you when you get the plywood cut. Would make things so much simpler. Luckily the design allows for small problems in the dimensions and you cannot see the faults in the final build
- I had assumed that a 7805 with a heat-sink would be sufficient to power the clock, as I had made a similar circuit before and it worked without any problem. I had not counted on the fact that these LEDs are behind a one-way mirror and consequently have to be much brighter. The first trial run had the processor hanging whenever the rainbow effects came on, the bluetooth module getting disconnected, etc. Thanks to friends on the arduino and fastled forums - I was able to sort this out. Bought an LM2596 module to power the LED strip separately. This module can pump out 3A with a heatsink. While this is still not enough for the 3.6A the strip can pull at full white, the software never turns on all the LEDs to white - so this is not a problem. Furthermore, I have added a night mode to the clock, so that the power supplies and LEDs can cool down at night - and hopefully prolong their life.
- The touch button is still giving some problems - but I think that is more to do with the problems in earthing in my house rather than anything else. Will try it at a friend's house to see if I still get the same problem.
- The proximity sensor does not work through glass. I had thought of installing the sensor behind the one-way mirror, but the glass blocks IR and hence the sensor does not work. I had to install it below the clock - its not big enough to be a distraction or look bad, but is not perfect either.
- Planning - I would suggest you plan all the features before you start building. My wife came up with the idea of converting this to a smart mirror (also) and I had to cut out the LCD enclosure with the limited tools I had at home (a drill and a file) - which was a problem. Had we planned for this enclosure earlier, we could have got a better finish.
- Costs - I had budget around 2,000 INR for this build, but we changed the design mid-way and added more features - so the final cost went over 5,000 INR. But I still love the final result :-)