How can I implement a HUD in my automobile?

December 16, 2005 2:42 PM

I want a Heads-up Display for my car.

I've done a bit of googling and found some remarks on DIY HUD systems, and I know that some newer vehicles have them, but how difficult would it be to implement a DIY HUD for my car? What would be involved in making it a true HUD (i.e. having it focus in the area "behind" the windshield)?

I think it'd be great to be able to have an IRC channel up during those long car trips. :-*

That, and GPS.

posted by cellphone to technology (5 comments total)

The distance at which the image will appear to be "behind" the windshield is just going to be equal to the distance from the windshield to the projection. So, if you want it to appear to be one foot out in front, you'll need to position a mirror one foot below the glass, at an angle, on which you shine the display image.

IANAOE
posted by odinsdream at 3:13 PM on December 16, 2005

Yeah, the point of a HUD is that it is in focus when you are looking at the road out the window, so you don't need to refocus or shift your eyes to see the readout. A crude way to do this is to put a magnifying lens a short distance from the display. I'm guessing a fresnel lens near the LCD display might do the trick, but I haven't tried it. I've only done HUDs via glass lenses and a point source (making a red dot sight in focus when looking at the target with both eyes).

Also, if you want a reflective surface to display the HUD that is more controlled than the windscreen, these are currently on sale for a few bucks. I have one on order with the vague eventual goal of a car HUD, but it hasn't arrived yet so I can't say whether it would be more or less useful than using the windscreen.
posted by -harlequin- at 4:12 PM on December 16, 2005

I think the simplest thing to do re lenses is just get some and play - to stand in for the LCD screen, just use a printed sheet of paper, then focus your eyes on something in the distance, put the sheet of paper at arm's length right next to the object of your focus, and put a lense or fresnel in front of it and play with the focal distance until the sheet of paper is in focus at the same time as the distant object. Then, whatever you've got in front of the sheet is a proof-of-concept for putting it (or something similar) in front of an LCD and mount the resulting unit so that it reflects in the car windscreen.

No need to use lenses that could ever work in a car HUD, even just playing with small plastic lenses out of toys can allow you to get a pretty good idea of what kind of optics you'll need and the magnitude. Then you can go shopping :)
posted by -harlequin- at 8:45 PM on December 16, 2005

You might want to start by mounting the screen from a laptop on your dash, facing the windshield. You'd need to get a cable so you could mount the rest of it where you could reach it. You may need to reverse the image on the monitor so it comes out right on the window. Your windshield probably has a compound curve which may also distort your projection, but you may be able to compensate.

You will need an easy way to dim it so it doesn't interfere with your view. You might tape off most of the screen and just use a one or two inch strip of that reflectorised glass along the bottom of your windshield for the display. You can also have a flip down display from the top, like a second sun visor. Don't let it block the center of the window.

There is a Raytheon NightDriver aftermarket system that will add an IR camera with HUD display to 'most any vehicle. If you got that you could add in your own visual feed. They might sell the HUD part seperately.

http://www.nightdriver.com/

http://www.amazon.com/gp/search.html/102-7818171-1133706?_encoding=UTF8&node=14023931&index=automotive&merchant=&showall=1&brand=Raytheon
posted by Ken McE at 8:46 PM on December 16, 2005

Err, ken, that's only for the hummer H1 and H2.
posted by lalochezia at 10:32 PM on December 16, 2005