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Experimenting with HUD via a mini-projector

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Having investigated all of the options for HUD navigation and the like, I've found all of them lacking. Most require placing a smart phone in a top-of-dashboard cradle with a flip-up screen. The HUD merely reflects the phone image onto the flip-up screen (or in some cases the windshield), which in most cases is not bright enough in daylight. All of these devices look like cheap add-ons.

I also looked seriously at Navdy, which seemed to be the best choice, even though it uses its own nav app. But further research revealed that the company is in the middle of bankruptcy proceedings and that product support would be in the toilet. Plus the device is a bit bulky and unattractive on top of the dash and for power it requires a OBD2 connection and a bulky top-of-dash wire run for the OBD2 cable. So I crossed that option off the list.

So my experiment now comes down to this: a top-of-dash mounted mini LCD projector (with a rechargeable lithium ion battery) that wirelessly mirrors the phone image and projects it onto the windshield. The projectors are not much larger than my iPhone X and some models have a lumens rating of 300, which should be good for daylight projection. I've also ordered a small piece of teleprompter glass to layer on the windshield back surface. This will provide a great reflective but transparent image (I think much better than the conventional reflective films that come with most HUD kits). I haven't yet ruled out the film option if the teleprompter glass doesn't prove to provide the results I'm hoping for.

If it all works, I'll be able to project Waze (or any other nav/driving app) onto the windshield and connect the sound commands via bluetooth to my car's sound system. Of course, Waze is my preference.

The mini projector arrives today, so I'll be able to do some initial tests and determine if it's sufficiently bright in daylight.

Stay tuned for further developments and results. Fingers crossed.
 
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Interesting project, @artsci. The wireless micro projector seems like a great solution.

A Model S owner I met at a Supercharger showed me the Navdy he was using. As you can see from this photo, the unit is rather bulky.

I have some beamsplitter glass in several reflectivity strengths (60/40, 80/20) left over from a project you can borrow if you want.

By experimenting with half-silvered mirrors, I've found that using a light absorbing material like black flocked paper on the reflected surface area (dashboard plane) increases the contrast dramatically.

I'll be following your progress.

navdy01.jpg
 
Just a general FYI
Without additional optics, the image will have the same focal distance as the emitting surface. This is in contrast to a purpose build HUD which produces a virtual image with a focal distance similar to the road. This reduces eye strain and reduces the time it takes to shift focus from the cluster to the road.
 
Interesting project, @artsci. The wireless micro projector seems like a great solution.

A Model S owner I met at a Supercharger showed me the Navdy he was using. As you can see from this photo, the unit is rather bulky.

I have some beamsplitter glass in several reflectivity strengths (60/40, 80/20) left over from a project you can borrow if you want.

By experimenting with half-silvered mirrors, I've found that using a light absorbing material like black flocked paper on the reflected surface area (dashboard plane) increases the contrast dramatically.

I'll be following your progress.

View attachment 270544

Thanks for the suggestion re the flocked paper. I'll get back to you on the beam splitter glass. Also the projector I tried did not sufficient brightness to work in daylight. So I'll be exploring other options.