Originally Posted by Acelius
This looks AWESOME!
it looks so relaxed. you should make a tutorial for this :P
it looks awesome mate, keep it going.
Here's a run down of how I made it.
Wood: approx 1/2" x 12" x 2 5/8"
Magnets: 1/2" x 1/8" N48 Discs
Qi PCB/Coil, either buy direct or yank out of another charger.
I started with a block of walnut which was 1/2" thick, 12" long, and just a little narrower in width than the phone itself (about 2 5/8). I made it narrower than the phone, because my fingers naturally extend past the sides of the phone when I grip it. This makes it relatively simple to center the phone, left-to-right, on the stand. I started by cutting the 12" board down so I had one piece that was 6 1/4" long which would be the face, and the remaining piece would be used as the base as well as some waste area to dial in the hole depths with the drill press.
Next, I had to lay out the holes for the magnets. The metal discs in the phone back are 49mm from the top edge of the phone to the center of the upper-most disc. The 4 discs have their centers at the corners of a 36mm x 36mm square. This began with finding the center-line of my block of wood, and then drawing parallel lines, at a distance of 18mm on either side of the center line.
Then, I drew perpendicular lines at a distance of 49mm + 5/16" reveal (~2 1/4") from the top. And another line, 36mm further down from that.
Lastly, I had to find the center of the square so I could accurately drill for the coil.
Then, off to the drill press to drill the holes. I drill the 4 holes for the magnets first, using a 1/2: Forstner bit. You could also use a brad point bit, or a twist bit, but the entry hole wont be as clean with the latter. Then, I used a 2" Forstner bit to drill for the coil. I drilled each hole about as far as I could go without the spur (center point) of the drill exiting the face of the board.
When all was said and done, the result was this:
The deeper you can get the hole, the better. This really is a game of millimeters. When I drilled the holes initially, a single magnet in each hole wasn't enough to hold the phone. But, with two magnets in each hole, the phone couldn't detect the charger through all the wood. I drilled the the larger hole as deep as I dared, because air has a lower permittivity (easier for EM fields to pass through) than wood. Still, even with a bunch of wood hogged out, the distance was still too much. I had to make the magnet recesses even deeper in the hopes that single magnets would hold the phone, thus allowing the charging coil to sit super low in the block of wood. After having drilled those magnet recesses as deep as possible with a drill bit and not being able to drill any deeper, it was time for a more risky manuever.
That's a 1/2" carbide end-mill chucked into the drill press. I bored straight down, getting the holes to withing 1/32" of the face of the block of wood.
This worked for me and I didn't, at any time, feel that I was in harms way. The wood, router bit, and drill press did not, at any time give any indication of any impending problems. Still, router bits are designed for the significantly higher speeds of a router, and drill presses are only designed for axial loading. If you are going to ever put a end mill in a drill press, please do not induce sideways loading on the bit. Go read up on drill presses and tool tapers and why this would be a bad idea. Do this at your own risk! END OF SAFETY WARNING
Next, I laid out the recess for the PCB of the charger. I took the coil of the charger and affixed it to the back of the PCB using double-sided foam tape. Then put the coil into the hole and traced around the PCB.
Then, with chisels and a router plane, I excavated the waste. You can use a router, drill bits, whatever you want to eliminate the waste. I also cut out a recess for the coil wires that looped up to the PCB, and I also included a 1/2" thick slot to accommodate the USB plug and cable. After this was all done the piece looked like this:
Next, came the base. This is from the same block of wood as the front, so the color and dimensions all match the front block. Both ends received a bevel of whatever angle felt "right". I held the front block on my desk and angled it back until it was pleasing. This then was set as the angle for all the bevels. If I had to guess....it'd be about 15-20 degrees.
I also had to cut a 1/4" in groove, from front to back, to accomodate the USB cable. The base ends up looking like this (as a note, the top face in the picture will be resting on the desk. I turned it bottoms-up to show the groove)
Next, I glued the base to the front using an extra thick/gel super-glue, as this was a fairly difficult piece to clamp. Traditional wood glues would be difficult, but not impossible, to use. Using the same glue, I glued the magnets into their recesses. I made the polarities all line up, so on the face, all the magnets have the same North-South orientation. I don't think this is critical though.
Lastly, I dropped in the coil. It is not held in place with any glue or screws. The coil has a ferrite backer and the magnets end up being close enough to hold the PCB in place. They don't actually contact the magnets, but I doubt it matters as the coil appears to be insulated. The USB cable slides up through the bottom through the channel that was cut earlier in the front block.
Turn it over, plug it in, and you are set.
The only other thing remaining which I plan on doing, is ordering some nano-suction polyurethane material to held hold the stand to the desk. But that's just peel'n stick and should be easy enough for most people to figure out.