How do you activate your augmentations in Deus Ex Human Revolution?
Solution 1:
When I played on the Xbox 360, they were mapped to the D-Pad. This appears to be the way they are mapped on the PS3 as well. The orientation of the augments on the display indicated which one was activated by which direction on the pad.
On PC, it's the function keys (F1-F4). You might want to check out this keyboard layout page. It lists the controller layout on consoles, and I assume the default keys on the PC.