HDMI over Cat6 switch? - Page 1
Forum section: electronics / projects

author: zigenz
author_rank: Newbie
timestamp: March 28, 2020, 07:52:30 am
content: Hi all,So given I'm now house-bound (Mrs. pregnant, so not taking any risks), I'm looking for a little distraction project.When we built our house, I plumbed Cat6 everywhere, all routing back to a switchroom. My boys like playing the XBox360 and PS4, which both live in the switchroom, and the video goes over Cat6 using one of these:https://www.aliexpress.com/item/32972733236.html?spm=a2g0s.9042311.0.0.7c304c4ddWqvTI(which works beautifully).There are two TVs in the house that the boys regularly play on, and it gets annoying having to swap them over manually (i.e. taking the receiver from one unit to another) all the time, as well as swapping the HDMI input on the transmitter (less of a problem as they MOSTLY play on the PS4). Ideally, what I am hoping to do is as below (red line = HDMI cable; blue line = Cat6 cable):Note that for the HDMI Switch, I am using the following:https://www.aliexpress.com/item/32961247582.html?spm=a2g0s.9042311.0.0.5c744c4dgcDnFrI'd like to develop is the "Magic Switch" as pictured, and this is what I am hoping for some guidance on. I'm doing some OpenWeave development at the moment so it should be fairly straightforward to integrate "Hey Google" actuation as well.As far as recon goes, I popped the covers off the HDMI over Cat6 extender I am using - main components are (unsurprisingly) a power stage, line magnetics, MCU and video unit. Picture is below:Power is supplied on the TX side (12V), and it uses (some variant of?) PoE to power the RX side. I measured the line voltages on the RX side, and it doesn't seem to be congruent with typical PoE (no expert however, so could be wrong) - no line-line voltages exceed 12V, . I looked up the datasheet for the GSV5100 (video unit), and all I found was the following:http://www.gscoolink.com/en/?ac=cp_show&id=16. I'm going to email the guy for a datasheet now; hopefully I get some purchase from these guys.SO: Given my background,the control and management side of things is easy, however the signal part is tricky. My first thought is to pull the power off using conventional magnetics use 8 channel analog switch with sufficient signal bandwidth, and then recouple the DC using conventional magnetics again. I could be (i.e. probably am) entirely wrong however.Any thoughts / guidance MOST appreciated!Cheers,Z

author: roman.isaikin
author_rank: Contributor
timestamp: March 28, 2020, 07:24:58 pm
content: You probably need HDMI matrix switch, seems like there is a lot to choose from. Would be cool to DIY this, but at these data rates - not sure if it could be done. Especially since all the good stuff is under NDA.

author: The Soulman
author_rank: Super Contributor
timestamp: March 28, 2020, 08:41:32 pm
content: These cheaper hdmi over cat extenders don't adhere to any Ethernet or tcp standard.Easiest solution is to get another set and use a hdmi splitter to feed both simultaneously.

author: zigenz
author_rank: Newbie
timestamp: March 31, 2020, 04:10:47 am
content: I get what you guys are saying re. the switches etc. - but I'm not keen on that for two reasons. Firstly, it's not as clean to integrate my desired automation functionality, and secondly, well, it's no fun.Anyway, I found the following which I suspect will take care of the switching part:https://www.diodes.com/assets/Databriefs/PI3DBS16412-Product-Brief.pdf. Looks like Pulse also make suitable magnetics:https://www.mouser.com/datasheet/2/336/HD8004FNL-911375.pdfSO it seems as simple as:Bob-Smith terminated magnetics on the signal coming in75-ohm impedance controlled, length matched, differential pairs from the input magnetics feeding in to the PI3DBS1641275-ohm impedance controlled, length matched, differential pairs feeding out of the PI3DBS16412 onto two sets of magnetics for the outputsa radio-enabled micro (prob go with a Nordic nRF52840) to facilitate control of the PI3DBS16412 and OpenWeave automationsome means to switch the power between the two outputs (thinking pairs of low Rds-on mosfets)It's all low-power stuff, so hoping I can just siphon-off some of the PoE power for this box.Any other recommendations? Board layout? 2.4 GHz antenna options / placement? Etc.?Cheers,Z