I bought this inductive QI charger which is designed for cell phones, but also charges my Nexus 7 tablet. The only problem is that the tablet needs to be precisely centered to be charged, which takes a bit of effort to get exactly right, and if it’s bumped off center it stops charging. So I built this frame that sits over the top of the charger and holds my tablet exactly centered over the charging coil.
It’s made up of 3 layers of laser cut plywood, one around the charger, and two identical ones to frame the tablet. It even has nice finger slots to make it easy to remove, a feature I identified as necessary in my cardboard prototyping stage….
You can download the files from Thingiverse @ https://www.thingiverse.com/thing:2734516