Hacker News Reader

Comment by astrodust | Hacker News Reader

I've often wondered about this as well. A Raspberry Pi 2 seems to have enough horsepower to act as a very capable KVM type unit, and has an Ethernet port.

How hard is it to digitize analog VGA or interface directly with HDMI and encode to something like VNC using the GPU if necessary?

View on HN

I've been fiddling with this idea for a while and have basically come to the conclusion direct VGA capture isn't worth the trouble. There are VGA to HDMI converters available for about $20-$30 that do the job surprisingly well. There used to be a number of VGA -> digital chips available (TI TVP7002, etc) but they've all been EOL'd or NRND (Not recommended for new designs.)

For HDMI/DVI capture at this scale, the best option seems to be an FPGA based system. There are several boards available that have the necessary hardware but are expensive (relative to a 1-port IP-KVM), power hungry, or large (or all of the above.) The Digilent Zybo may have enough to pull it off (and has the ARM cores to boot) but is still a bit on the pricey / power hungry side. I'm hoping the new Snickerdoodle Zynq based boards will be able to do the job (with an add-on board)

Regarding using the Pi2, it might work, especially if it can be fed via the camera interface. The lack of USB-OTG (linux gadget support for KB / Mouse / Mass Storage) limits the usefulness somewhat.

I've been hopeful about the Beaglebone Black / X15 due to the USB-OTG and the tons of extra IO.

The other board of interest is the Dragonboard 410C - it can supposedly capture at 1080p60 (more than enough for the average system you'll stick a KVM on) but I'm not sure what that means explicitly (yet.) It does have USB-OTG (though it can't do USB Host / Device simultaneously.)

There is a board that'll pull hdmi to the CSI port. It's abou 150 euros, but there have been success reports, up to 60 fps

http://www.auvidea.eu/index.php/theme-styles/2014-12-30-22-3...

Regarding emulating a USB device, first thing that comes to mind is possibly using a micro of some sort that can act as a usb device, like an arduino or teensy. it's a bit hackish, but sending things over SPI should get more than ample speed for keyboard/mouse emulation, and there's code written already for a lot of micro platforms to do both.

This is currently under development but need some funding.

https://www.nexlab.net/product/rasky/

Rasky is a low cost open source (hardware and software) KVM over IP built on top of the well known RaspberryPI model 2B featuring VGA video capture, USB keyboard and mouse emulation, remote control both by web (ajax VNC) and VNC, remote relay switches and digital inputs.

I'd prefer a 8-48 port version at <$50/port.

http://y-salnikov.github.io/vcaptfx2/ is cheap

I have a bunch of $200-300 devices (from blackmagic for hdmi, or raritan for vga) to do this. It's doing 48 ports, with good OS/security, for $10-50/machine, which is hard.

Reply on news.ycombinator.com