If you recall, in the last update I mentioned offhand an idea to integrate an induction coil and charging circuit into the adjustable phone dock mounted to my bike's handlebars. Well I got the spare Qi charging mat in the mail today, and wasted no time prying it open:
I was expecting a more rectangular induction coil as I've seen many devices like this use. No big deal though, the question becomes how to mount the coil and PCB (printed circuit board) in an unobtrusive way. Here was my first attempt:
...But then, if I mount the coil like this, where does the PCB go? I can't just leave it hanging off one side. That would look janky and ugly as hell, I wouldn't stand for it. Surely there has to be a better solution than this. Here's what I came up with:
After peeling away the foam backing from the coil, there was room under the phone for both the induction coil and the PCB. I had to mount the PCB way to one side so the micro USB port is clear of the edge of the phone, since most micro USB plugs are pretty fat to make them easy to grip.
This was my solution for mounting the indicator light. It's not perfect but I can see it fine, which will help me diagnose problems if anything ever goes wrong with this setup. Tired, satisfied and with dried superglue on my fingertips, I took it out for a test ride.
Obviously since my phone is my only camera, I can't take a picture of it in the dock, but it fits. Barely. There is just exactly enough clearance left that the phone, sitting on top of the charging coil and PCB, still fits when the corners of the dock are drawn inward by the securing mechanism.
Do you see those two cables going into the body of the bike? One of them is the USB cable from the finished inductive charging dock. Right now it just goes to a 4 cell 18650 power bank snugly tucked inside the bike's body. That's not an ideal solution obviously, I have to laboriously open up the bike to swap in a charged power bank when it runs out.
The long term solution will be to buy or build a passthru circuit that goes between the battery and motor controller, which leeches 5 volts 2 amps from it solely to power the phone charging dock. Alternatively I could mount a 7 watt solar panel to a pannier above the rear wheel and use that to power it. Thoughts?