A free HUD (head up display) for your car
If you would like a fee HUD, there is only one requirement, apart from owning a car. iHUDlite (not to be confused with a different app called iHUD) is a app for the iPhone. As with many apps, it comes both as a free version and a pay for version. It works very simply. It uses the GPS capability to of the iPhone to determine your altitude, direction and speed. The clever part comes in the way in which the display can be configured.
One of the options is to choose to display the speed only (in one of three different colours) and then to reverse the display, as a mirror image. The iPhone is placed on the dashboard and the image is reflected off the windscreen.
Having tried the software, I found it works well at night, but the image is far too weak to be clearly seen in daylight. Also, the glass in my windscreen is double-glazed, giving me two images. The other problem is stopping your iPhone sliding around on your dashboard. I am off to the Pound Shop tomorrow to get one of those non-slip mats you can put on your dashboard. The app also has a database of the speed cameras in the UK, but I have yet to try this feature out.