I plan to make a slowly rotating dais (around 20cm circumference for USB-powered WS2812B lanterns, or similar small devices. The USB connector can't be rotating, so there needs to be a non-rotating base, where I might also put buttons for manual input. A small stepper rotates the platform.
The question is how to connect the non-rotating base (= "bottom") to the rotating platform (= "top"). I have a couple of ideas:
(1) a splitring for all of the connections.
(2) a splitring for DC power, and an ESP12 WiFi module in the bottom to manage the buttons (and also remote control) and run the stepper, and an ESP12 in the top to run the lamp; the pair of ESP12s communicate as necessary over WiFi.
(3) A pair of ESP12s as above, but a wireless charger transmitter/receiver pair positioned around the motor shaft to supply power to the top part. No splitring required.
I'm considering the pro/cons as below.
(1) splitrings are relatively expensive, and limited. Fiddly mechanics.
(2) flexible, mechanical is fiddly.
(3) flexible, uncertainty about interference, EMF shielding etc.
Any thoughts or advice? Or alternative approaches?
I think I would go for the split ring, as it is simpler in general. For a fixed installation, the ad hoc ability of Wireless Power Transfer is nice but not really required.
However, I am intrigued by the possibility of WPT, since modules can be bought quite cheaply, and I might buy some to experiment with. I would probably consider 433 MHz transmitter for comms.
Update: I've decided to go for the pancake style slip-ring for power transmission, because I think I it will be easier to make robust. (The cheap split-rings I've founded don't have much surface to bond to). For the pancake slip-ring: on the one disk is ring pads printed on a PCB with copper-rings layered on top, and on the other disk some micro motor graphite brushes (I've ordered some 3x3mm) which should be easily mounted in some square tubing on the facing PCB.
