I would contact the host of the presentation and see how their setup works. I copied the information below from a 2010 posting. Hopefully the host has a usb interface for the projector (similar to what some mice have as a transmitter from the usb port)
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So you want to use the projector as the monitor for a computer, but you want to use wireless to join them?
You won't be able to do that using an Airport network. Computer networks can only pass data that's been specially formatted. They can't pass video streams in a form that a monitor or projector can understand.
To do this you need a video sender - a device that accepts a video feed from a TV, DVD or satellite box, then sends it wirelessly to a receiver which you connect to your TV or projector. In your case, you would need an S-Video output on the computer to connect the sender, then connect the receiver to the S-Video input on your projector.
Problem is, video senders don't work as well as cables. You'll get some degradation of picture quality (noise) and possibly some interference from other wireless devices (dropout).
If you want to watch video that's stored on a networked computer, with decent picture quality, you'll need to connect a computer or a network media player directly to the projector using a HDMI or DVI cable.
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