How to Build a HUD for your Car | Hacker News Reader

How to Build a HUD for your Car

bwongtech.blogspot.com

59 pointseksith21 comments

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.

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...)

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.

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

Exactly, unless the cars already drive themselves, this would always be considered dangerously distracting in the best case scenario.

Hey I'm Bill Wong, the guy that wrote that blog post. The glass on this design was mounted with suction cups (no tape) and placed about where the tree line is in the driver's field of vision. I didn't feel it was obstructive for normal driving, but it did sometimes get in the way when looking or turning left.

I'm still working on this project, and I hope to solve this issue in a future design. Any suggestions on how to securely mount the glass without obstructive supports?

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.

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.

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...

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.

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

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

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.

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.

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.

You can also buy a GPS-based one on Amazon: http://amzn.com/B005X4QCAA

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).

I was going to mention this if someone else hadn't. Also, here is my solution to viewing data from my car http://csmatt.com/notes/?p=5 . I use and love the Torque app (as seen in the last pic)!

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

*me

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)

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.

Reply on news.ycombinator.com