USB through 'Miniature Slip Ring'

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orbitronics
 
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USB through 'Miniature Slip Ring'

Post by orbitronics »

Hello beautiful Mike and Co!

I am keen on using the "Miniature Slip Ring - 12mm diameter, 6 wires, max 240V @ 2A" in a project - it seems perfect for me but i wanted to ask your opinion first:

if i twist two of the wires and assign D+ and D- to them from a USB, should be work ok? My bandwidth in the project tops out at around 5 MB/s which made me wonder what you think the bandwidth could top out at when using such a rock and roll means to carry a differential signal?

I realise the adafruit page says 28 AWG while the datasheet says 26, both work in terms of gauge but impedance matching is something i don't fully understand, and I assume the thing that could stop it from working.

Hopefully my finished project will be on display at UIST or SIGGRAPH.

Thanks !

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adafruit_support_mike
 
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Re: USB through 'Miniature Slip Ring'

Post by adafruit_support_mike »

Hmm.. it can’t hurt to try, but I’d hesitate to bet on it.

Slip rings can inject noise into a signal as the contacts slide across the rotor plate. OTOH, millions of VCRs worked just fine with a fast-spinning read/write head and slip ring connections.

Low-speed USB (USB-1.0) operates at 1.5 Mbps, and full-speed (USB-1.1) operates at 12Mbps. There are no rates in between.

The nature of your rotating contact will be an issue, but trying won’t cost you more than the price of the slip ring and a chopped-up USB cable.

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orbitronics
 
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Re: USB through 'Miniature Slip Ring'

Post by orbitronics »

I just ordered a bunch and will try them out as you suggested.

I do use the FT232HQ on asynchronous 245 FIFO mode to get at least 5MB/s as that is the bandwidth the software spits out - though i still can't figure out how to properly measure the actual bandwidth through a usb bridge.

I'll let you know how it goes

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