

How to Build a HUD for your Car - eksith
http://bwongtech.blogspot.com/2013/02/how-to-build-hud-for-your-car.html

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diminoten
It doesn't solve the #1 problem all HUDs have to solve - view obstruction.
That's a _very_ significant portion of your view being effectively removed by
the scotch-taped + suction-cupped piece of glass which _should_ be
transparent.

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millzlane
There is a reflective tape you buy specifically for cars that came with HUD
from the factory. You could also measure the tach signal for a tachometer too.

([http://www.ebay.com/itm/Head-up-display-OBD-II-
HUD-S-200-Typ...](http://www.ebay.com/itm/Head-up-display-OBD-II-
HUD-S-200-Type-reflector-sticker-film-one-piece-/140778303797))

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Cookingboy
From the pictures it looks like the projection is focused on the film (also
true for OP's link), where as in newer HUDs (such as my 2013 BMW) it looks
like the projection has infinity set as the focus thus achieving the result of
it looking like it's floating in a distance, and I don't need to adjust the
focus of my eyes to look at the contents of the HUD. But I have not reviewed
the tech spec, it just seems this way and the videos/pictures in OP's link and
your link look way too jarring.

~~~
tb
OP uses a fresnel lens and gives instructions on how to focus the HUD at
infinity to avoid this problem.

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ChuckMcM
Pretty cool, next up use a Raspberry Pi with a pico projector and you've got
all the data you ever wanted to distract you :-). I've noticed that some of
the HUDs on the market actually put the display fairly low on the windshield
so it is above what you would normally consider the dashboard but in terms of
what it is obstructing in the view its where your eyes would be looking at the
hood of the car.

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Amadou
Has anybody experimented with a pico projector? I've been thinking that a HUD
would be a fantastic application since some (most?) pico's have infinite
focus. Some of the newer ones are pretty bright too - especially if you only
need to illuminate a couple of square inches instead of a couple of square
feet.

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ChuckMcM
I've got two of them (both from Woot). One is 10 lumens the other is 15. Both
are fabulous when camping, they are pretty easy to watch indoors at a couple
of feet in all lighting conditions (10 - 18" diagonal) and mildly amusing in a
dark room at > 100" in size.

They do get warm so having them on the dash would either require some forced
air cooling or a different mounting system. Paired with a webcam they let you
reproduce the 'put a controller on anything' [1] stuff that Microsoft showed
off.

[1] [http://www.kurzweilai.net/wearable-projection-system-
turns-a...](http://www.kurzweilai.net/wearable-projection-system-turns-any-
surface-into-a-multitouch-interface)

~~~
Amadou
Have you tried taking one out to the car and shining it up on the windshield
during the day? Without any special windshield coatings you'll get a double-
image, but at least you can get an idea of how visible and focused it would be
under normal driving conditions.

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damian2000
There's a recent update to this here:
[http://bwongtech.blogspot.com.au/2013/06/car-hud-
version-11....](http://bwongtech.blogspot.com.au/2013/06/car-hud-
version-11.html)

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hawkharris
Is this legal? My understanding is that most states have strict regulations
concerning any kind of light being projected from / on your windows.

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eksith
I'm sure there are some jurisdictions in which this would be illegal.

In some places, certain "traffic aides" are outlawed E.G. Radar detectors.
While it could be argued that this doesn't help you evade police, the fact
that it's an extraneous (potentially distracting) "thing" attached to the
windshield could be a legal hiccup.

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gknoy
I am less than keen on the idea of a loosely-fastened sheet of glass sitting
in front of my face. In an accident, that can't be very safe.

~~~
eksith
That's very true. To be fair, this is highly, highly experimental so first
iteration will be the proverbial ducktape and cardboard solution.

I think future versions will have the device embedded directly into the dash
and fastened someway to prevent dislodging in a crash. There are
polycarbonates that can take the place of glass to serve as both projection
surface and combiner (though these might be pricey).

Once attached using solvent, these are very sturdy. So sturdy, in fact, that
they're used in high capacity fish tanks.

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nether
You can also buy a GPS-based one on Amazon:
[http://amzn.com/B005X4QCAA](http://amzn.com/B005X4QCAA)

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ISL
Cool!

For a poor, but effortless, way to try out a HUD, the OBD app Torque has a HUD
mode that inverts the display. Put your phone on your dashboard while driving
at night, and you get a HUD-like effect (with a different focal plane).

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hudibras
I know somebody* who occasionally puts his phone on the dashboard like this to
watch movies while driving.

*me

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ISL
Please consider not doing that on public roads. The rest of us are out there
too.

(that said, I bet it works great. A movie in the mirror is still a movie)

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omegant
This is great, it shouldn´t be very difficult to adapt this design to an
airplane, with an ipad with a navigation app or something similar.

