Anyone built a Pi-KVM? HDMI/CSI adapter question

TangoEchoAlpha · 1 Sep 2021 at 13:41

Wondering if anyone has built a Pi-KVM on the forums? I am thinking about it as a project, so I could VNC into my work laptop from my main computer. Really it has to be a KVM solution as I can't install any extra software/run any software on the work laptop.

I'd be very interested if anyone has done it - in particular, which HMDI to CSI-2 bridge you used. The official docs suggest to use a HDMI/CSI adapter based upon the Toshiba TC358743XBG chipset and links to an adapter on AliExpress. I would rather buy an adapter/bridge more locally if I can and was wondering if something like the Waveshare HDMI to CSI adapter on the rainforest would work?

Or can I use any CSI/HDMI adapter? If anyone can suggest one to get from the usual Pi places, would be very grateful

jrwagh333 · 3 Sep 2021 at 08:40

Have you taken part in the Kickstarter for the HAT? Looks great.

TangoEchoAlpha · 3 Sep 2021 at 09:07

jrwagh333 said:
Have you taken part in the Kickstarter for the HAT? Looks great.

I'd seen it, but not backed it yet. Have you put in a backer pledge then?

jrwagh333 · 3 Sep 2021 at 09:14

Unfortunately it's too rich for my blood. I'm going to try and do it DIY

TangoEchoAlpha · 3 Sep 2021 at 09:17

jrwagh333 said:
Unfortunately it's too rich for my blood. I'm going to try and do it DIY

Yes, I felt the same. I'll quite happily donate / Patreon the Pi-KVM project if it turns out to be something I find useful, but felt that HAT was a bit pricey. Same for the TinyPilot, great idea but also more than I'd like to spend on a home KVM. I guess relatively speaking though, it's still cheap compared to a 'proper' IP KVM.

TangoEchoAlpha · 3 Sep 2021 at 19:13

@jrwagh333 I have just ordered one of these:

https://www.ebay.co.uk/itm/USB-C-PWR-Splitter-/203570218304

As Pi Hut and Pimoroni were sold out. Looks like one guy making them and perhaps the interest in Pi KVM of late has used up all his stock?

I've also got a HDMI/CSI2 adapter, went for the Waveshare one - so once the splitter arrives I should be in a position to try it out

jrwagh333 · 4 Sep 2021 at 08:20

TangoEchoAlpha said:
@jrwagh333 I have just ordered one of these:

https://www.ebay.co.uk/itm/USB-C-PWR-Splitter-/203570218304

As Pi Hut and Pimoroni were sold out. Looks like one guy making them and perhaps the interest in Pi KVM of late has used up all his stock?

I've also got a HDMI/CSI2 adapter, went for the Waveshare one - so once the splitter arrives I should be in a position to try it out

Had my eye on that USB splitter from PiHit, but like you said it keeps going out of stock.

Please let me know how you get on

Buffalo2102 · 4 Sep 2021 at 15:58

I built one to use in the same way as you - remote into work laptop which is completely locked down.

I used the Waveshare adapter you mention above and it works well.

jrwagh333 · 4 Sep 2021 at 16:32

Is it possible to link the adaptor please?

Buffalo2102 · 4 Sep 2021 at 16:37

I guess it should be OK since OCUK don't sell anything like it.

https://www.amazon.co.uk/dp/B095KJ2181?ref_=pe_27063361_487360311_302_E_DDE_dt_1

TangoEchoAlpha · 4 Sep 2021 at 17:07

Buffalo2102 said:
I guess it should be OK since OCUK don't sell anything like it.

https://www.amazon.co.uk/dp/B095KJ2181?ref_=pe_27063361_487360311_302_E_DDE_dt_1

Thanks for that link, of course it would be cheaper than the one I ordered - https://www.amazon.co.uk/gp/product/B08TBD68MH

Looks like exactly the same item :confused:

Buffalo2102 · 4 Sep 2021 at 17:19

It's gone up since I bought it too.

TangoEchoAlpha · 4 Sep 2021 at 17:25

Buffalo2102 said:
It's gone up since I bought it too.

Thought I'd chance my arm with an Amazon chat, see if I could get a credit for the difference. Nope, but they would be happy for me to return the one I have and place a new order with the cheaper one. Sadly common sense with Amazon policies did not take place

Buffalo2102 · 4 Sep 2021 at 17:26

Nice try though.

TangoEchoAlpha · 4 Sep 2021 at 17:33

Buffalo2102 said:
Nice try though.

I did make the point about the cost to Amazon in terms of processign the return and a new order, even played the 'environmental impact' card. Customer rep wasn't having any of it, be he's good at poker is all I'll say

What solution did you use for powering your Pi-KVM? I was getting ready to splice two cables together, but if that power adapter arrives then it might be a more elegant solution for not a lot of cash.

Buffalo2102 · 4 Sep 2021 at 17:39

I bought one of these - https://www.amazon.co.uk/dp/B07DS2RJY1/ref=pe_27063361_487055811_TE_dp_1

Then cut the power to the USB data leg. You could just tape over the power conductor in the connector but I though that was too fiddly and too unreliable.

TangoEchoAlpha · 4 Sep 2021 at 17:48

Buffalo2102 said:
I bought one of these - https://www.amazon.co.uk/dp/B07DS2RJY1/ref=pe_27063361_487055811_TE_dp_1

Then cut the power to the USB data leg. You could just tape over the power conductor in the connector but I though that was too fiddly and too unreliable.

Do you not get any low current warnings on your Pi? I ask as I had looked at other similar Y cables, but couldn't find any that were rated for ~3 amps like the official Raspberry Pi 4 power adapter?

The Pi-KVM project also recommends one of these if you don't want to start hacking cables, like a data 'condom' to prevent juice jacking, but this one removes the power pins - https://www.amazon.co.uk/PortaPow-USB-Power-Blocker-Cased/dp/B094FYL9QT

Buffalo2102 · 4 Sep 2021 at 17:52

I get an amber warning for undervoltage detected but I've been using it for around 10 hours a day, 5 days a week for more than a month now and haven't had a single hiccup with it. YMMV I guess.

TangoEchoAlpha · 4 Sep 2021 at 17:57

Buffalo2102 said:
I get an amber warning for undervoltage detected but I've been using it for around 10 hours a day, 5 days a week for more than a month now and haven't had a single hiccup with it. YMMV I guess.

Thanks, useful to know. Will wait and see if that £3 adapter turns up, otherwise I'll get a Y cable or get my soldering iron out (probably the latter)

TangoEchoAlpha · 5 Sep 2021 at 18:56

@jrwagh333 The USB C adapter is back in stock on Tindie

https://www.tindie.com/products/8086net/usb-cpwr-splitter/