I have a small Emax RS2205 2600kv 16v DC Motor that is turning a PCB with IC chips that needs to be powered.

Emax motor

I want to send 2 power cable (VCC and GND) from to stationary battery to the rotating PCB.

Here's what I am trying to build:


I can't use slip ring because of the engine will be hitting some high RPM. Though if you are aware of a miniature high RPM (2000+) 2 channel 5v slip ring please recommend.

I couldn't find brushless slternators, nor rotary transformer that are small in size that can pass 5v either.

What is the best miniature lightweight solution for transferring power for such system?

Thank you


I found a wireless charger, it might work, though I'm afraid it might damage the arduino which is going to be placed on top of it, or right next to it

  • 3
    \$\begingroup\$ it is possible to use (electro)magnets and planar coils to generate a voltage on the spinning pcb. you will need some form of regulation to achieve your 5V though. Bonus point : thos coils can double as rpm meter and/or braking system \$\endgroup\$ – Sclrx Nov 10 '17 at 8:51
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    \$\begingroup\$ You could use another small motor (run as a generator) with the rotor locked to the fixed housing and the stator (with coils) attached to the spinning plate/circuit board. \$\endgroup\$ – Jon Nov 10 '17 at 10:20
  • \$\begingroup\$ How much power at 5 V do you need? \$\endgroup\$ – winny Nov 10 '17 at 11:11
  • \$\begingroup\$ @sclrx I found something that can do the job, I linked it in my answer. Do you think the magnetic field will affect the engine or the microcontroller? Also I'm curious, how can it be used as an RPM meter, that might be usefull \$\endgroup\$ – Joseph Azzam Nov 10 '17 at 11:47
  • \$\begingroup\$ @winny enough to power 100 SMD RGB LED, and the microcontroller \$\endgroup\$ – Joseph Azzam Nov 10 '17 at 11:47

I would recommend a wireless charging solution as the probably cheapest solution. You could even embedd the receiver coil in your PCB. Or just buy ready to use transmitter and receiver.

Edit: It is very unlikely that the relatively weak magnetic field (compared to the motor) of the wireless charger transmitter coil will affect the motor. It is a little dependent of the position of the coil. The magnetic field strength gets weaker exponentially with distance.

I cant really recommend any specific products here but there are of the shelf solutions of transmitter as well as Receiver modules if you dont want to develop something yourself. If you are aiming for a new development i would search for application notes of wireless energy transfer controller ICs (Qi standard etc.) as a starting Point.

  • \$\begingroup\$ Wouldn't the generated magnet field affect the rotating engine? Any tips on how to set it up, and do you have any recommendation for pieces to use? I know it's too much to ask, though if you can give me starting point to start researching it would be tremendously helpful \$\endgroup\$ – Joseph Azzam Nov 10 '17 at 11:10

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