Cameras and TV for presentation

[UtwigMU]

At work we're building new presentation room for 10-20 people. The presenter will prepare some ingredients on the counter in the middle front and in the back. He will also use slides on laptop. I'm thinking good large TV for display but what about cameras and connections. I think an overhead cam and one pointed at equipment in the back, so that attendants can see his hands. This setup might be used in some weeks but not others. The presenters are not very good at computer tech.

So what should I research in cameras? POE security cams with a tiny PC connected to main screen? What do I use for presenter to switch cams?
Some sort of stills/video cams on batteries would not work as they are too complex. The presenter needs to come in, turn everything on, start presenting and then maybe use tablet to control what is on the monitor behind him.

Also how long can HDMI run? I tried HDMI over LAN extender once and it was so-so (OK with HDMI but not when converted to display port.

What is the state of wireless displays, WIDI - I was trying this a couple of years ago with Asus dongle and it didn't work.

I'm asking for points in direction to research.

[VJ]

My first idea would be simple cameras with RCA video connectors and a video selector box, where the presenter just presses the button for the source he wants. Only problem is if that this is complicated if you have hdmi, vga and rca sources, as you would need to switch the video input on the projector as well (not sure how a projector will auto-select an input when there are multiple signals) or need to convert everything to the same type of signal (e.g. with rca-hdmi converters and then a hdmi switch); best not to rely on the autoswitching as a new projector may behave differently. This could of course also be solved by connecting all video sources to the projector and using its remote control to switch the input (but I agree that not all presenters are capable of that ), provided you have enough inputs on the projectors.

In one of the auditoriums where I taught, there was a small control panel on the presenter's desk. It had a touch screen and offered controls for everything: lights, projector, screen, blinds and sources. It was an off-the-shelf solution (customized), but I don't know the manufacturer. However, I don't think it should be that difficult to make a simplified version: most more professional projectors have a serial port which offers control over sources and power; a simple Arduino with a few physical buttons might allow you to make something that has a few relay switches and communicates via a serial port (no touchscreen required even). You would then just have a button for each source (which you can label), and buttons for power on/off. No risk of wrong presses on the remote of the projector. Depending on the number of inputs on the projector, you may not even need a video switch box (but you will need multiple video cables running up there). If you would need more inputs, the Arduino would have to control the video switch box as well... It would completely remove any software aspect for switching video sources... This may be a good thing or a bad thing... Positive is that if you need to use another computer, there still is the capability of switching the video.

edit: about hdmi cable length. From what I read, it depends on the quality of the cable and the source (laptops give weaker signals, decent home cinema amplifiers give strong signals. I use a cheap 12m cable from my home cinema amplifier to my projector without issue, but I've read other experiences. There are amplified hdmi cables to bridge longer lengths, or - as you say - hdmi over ethernet (Did you use hdmi over lan or hdmi over ethernet? Hdmi over lan generates normal network traffic which you can even route through a switch; hdmi over ethernet requires dedicated cables for the video connection, which you cannot pass through a switch). No idea on the state of Widi.

[UtwigMU]

I used HDMI over ethernet (HDMI > Box > 2 dedicated CAT5E cables > Box > HDMI)