Hi everybody !

I am working on a project where I want to make a platform to spin thanks to 4 embedded DC motors. So the supplying has to be wireless.

My problem is that the current limitation of the wireless receiver is to low. Then, when I control the motors (with labview connected to the embedded arduino nano by bluetooth), if the PWM value pass 80, everything stops for a second and the bluetooth is disconnected.

So I would like to find a wireless receiver that can provide more than 1100mA. Do you know if I can find one ? For now, I use a wireless android phone charger. Maybe I can override the current limitation by modifying it ?

Thanks for reading, don't hesitate if you have any question or advice

 

You can get more power from conventional circuits by raising the voltage on the driving end and making the "antennas" (if that is what they are called) much larger.

Might it be easier to make a transformer with a pot core and place it in a shaft in the center of the platform where there are two coils within the pot core, one being stationary and driven with high frequency AC, the other coil rotating with the platform? I

https://en.wikipedia.org/wiki/Rotary_transformer

 

Thank you for your answer. Okay, I think I understand.

I am not sure that the stationary emitter is supplied by high frequency AC. It is just connected to a computer with a USB cable with a little electronic circuit... For now, we are using a basic wireless supplier bought on amazon or aliexpress.

We will first try to put two receivers instead of one, to see if we can get more power. If it doesn't work we will follow your advice and try to make the antenna larger.

Thanks

 

For completeness: for a given antenna size you can obtain more power by raising the frequency.

 

Can we see a picture of your platform and motors?

 

I would think that if you wired two of these in parallel you would have a fair chance of getting the output current you want.

https://www.ebay.co.uk/itm/Qi-Wirel...Android/253510345925?var=&hash=item3b0664e4c5

Many are available on ebay with specs claiming an output of 1000mA. I would not be surprised if that 1000mA is only achievable under optimum conditions – bear in mind that the unit spaced further from the charging base will have a lower output due to the reduced magnetic coupling.

 

Can we see a picture of your platform and motors?

Sure !

Sorry for the (huge) delay, I'm working on serveral projects at the same time... here are some pictures

I changed the resistors just before the motors so now, we can send a PWM command of 255 (100%), but the platform is still slow as the current in the motors is low... the problem is still here.
We bought a more powerful power supply, maybe it will work... We will test it next week

Thank you for your answers !

Quentin

 

I have been close to writing something about:
Why is contact less energy transfer chosen when something so simple, but old-fashioned, as a slip ring may be able to handle the task.

 

I have been close to writing something about:
Why is contact less energy transfer chosen when something so simple, but old-fashioned, as a slip ring may be able to handle the task.

Hmmm that's a good idea. I don't know actually. I am just trying to make everything work with what I have. The project was already started when I arrived. If the wireless is definitly not working I'll suggest it.

But I have got an update. I tried to use two coils instead of one and I really can't understand what is happening... I drew something to explain, in the attached files.

Thanks for your help