Best way to get IR focus assist on a 7D?

Hello,

I'm after a means to get IR focus assist without the cost of a Speedlite. I don't do flash photography as such and have no current or future need for a Speedlite. I know there is a transmitter that does the IR focus assist but I cannot find out how well it compares to a Speedlite such as the 430 EX II. As with my question about lenses, this is for taking family photos in low light, without blinding people with the popup flash.

TIA