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Closed-loop VR setup for Rancz Lab
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Investigate through hole slip rings to support rotary stage communications and air flow #1

Closed glopesdev closed 1 year ago

glopesdev commented 2 years ago

The communication between the rotary stage and the base requires a slip-ring with a through hole allowing air flow to sustain free ball movement. If the VR computer is to be placed outside the platform, this will be one of the main challenges to overcome.

ederancz commented 2 years ago

SPINNER suggested by Jon Newman: ONIX commutator BOM Emailed Spinner today, waiting for a reply.

TODO: minimal and ideal specs (RF, number of channels, number of power lines; dimensions; potential alternatives to a through-hole?)

ederancz commented 2 years ago

A questionnaire from Spinner was received today with the somewhat cryptic subject: Hybrid rojo. RF communication analogue and digital lines plus power ones : RFI ? Sorry for the atrocious formatting.

Thank you for your RFI. + RFQ. for 1 pc. of an hybrid rotary joint ( coaxial rojo ,  + slipring) , hollow shaft - through-hole diam. 12,7 ? mm It should support RF communication and have several analogue and digital lines , plus a few power ones (~25V, ~2-3A).   Specification details RFI. :

A general characteristics : a Which hollow shaft - through-hole diameter mini.  ? b Which rotation speed  Nominal ?  /  max. ? c Which environnement condition :  protégé ? non protégé ? d Which duty cycles mini. ?   B RF communication : a How many channels (Tx. , respectively Rx.) ? b for each channel :           i. Which useful frequency band ?                  ii.      Which power : 1 Peak max. ? 2 CW. max. ?

C analogue lines :   a how many lines ? b The specification ?

D digital lines : a how many lines ? b The specification ?   E few power lines (~25V, ~2-3A).: how many lines ?

RoboDoig commented 1 year ago

https://www.rotarx.com/en/slip-rings/usb-slip-rings/

RoboDoig commented 1 year ago

Of the companies I've contacted about hybrid slip rings (rotarx, moflon, senring) all are able to supply a slip ring with 5+ USB lines and power lines + through-hole for airflow. I don't have a firm price for all of them but we are looking at about $500 so far.

One further consideration is that USB 3.0 standard slip rings use an optical fiber for signal transmission and are not compatible with through-holes. In case we need USB 3.0 the slip ring would also require an airflow union which rotarx can provide.

ederancz commented 1 year ago

I suggest we keep it simple for now and go with USB2 slipring options, with the assumption that we can find suitable USB2 cameras for pupil tracking. In future updates, the addition of fibre optic channels (rather than USB3) would be interesting.

RoboDoig commented 1 year ago

Closing issue as slip rings are purchased and tested.