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george

First person viewing glasses - direction sensing

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I'm looking at building a small ROV with a 2 axis panning camera (2 micro servos) I want to be able to have video glasses with a sensor of sorts to tell it in which direction your head is pointing.

I've thought about a 3 axis hall effect sensor - and using the earths flux lines as a reference. But the ones on the market seem to have either too low res - or they have a settling time of just under half a second - which I think would make you feel sick. I've also thought about using 4 photodiodes mounted 90 degrees to each other in a corner cube type configuration, and having a modulated IR LED on a console - the diff quantities of modulated light that each diode would see would put out a corresponding voltage and hopefully see which direction yr head was pointing in. However I feel it would be very difficult to get the actual angles close to what they actualy are in real world conditions, which would make you feel pretty sick pretty quickly. :blink:

I've heard that a few people on this forum have done it - and would like to know what works - and what doesn't, and how successful they are.

Many thanks

Brendon

Edited by george

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I had good success with IR diodes on stalks mounted horizontally across the top of my transmitter diode to diode distance of about 18" The pulse modulated LED emitter was mounted on my VR glasses. It worked very well although I never formalzed the design. (too many interests). A gain control helped get the servo tarcking angle to track roughly the angle between my head and the transmitter. The mental adjustment was easy.

T.I.

Edited by Temporary Insanity

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I have a working gyro-based design in one of my drawers :(

In fact I wanted to improve its precision but I've always had other things to do. The new design is laid on paper but not more.

I really should continue this, but the lack of good vibration-proof mechanics for the camera has not motivated me a lot. I'm also too unsure of what to use as an output signal... I've done it with 2 analog outputs that are designed to be connected to extra channel inputs in my TX. But later I've seen that many new TX's come already fully equipped so there are no more free channels. So with these ones I would have to use the buddy port, which is totally different. Seems there is no universal solution, which is what I first wanted to do..

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I'm glad to see some other people trying this, but the LED/gyro/etc. approach most people usually come up with has proven to be either too expensive, inaccurate, slow, bulky, etc., etc. I was successful using an optical quatrature scanning device I built. I originally did this back in 1993, but I'm sure an off-the-shelf (COTS) optical mouse could now be used as the quadrature input sensor (I will gladly communicate how to do this, if anyone is interrested). Actually, I've been considering re-applying my original design using an optical mouse. I also tilted the cameras up and down using an accelerometer as the input device mounted to the top of my head. Worked quite well!! Hope this helps.

Dr. Mike

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Doc, if you are inferring that the IR LED device that I came up with fits any of your casually offered descriptors ("...too expensive, inaccurate, slow, bulky, etc., etc."), I take direct acceptation.

Thank you,

T.I.

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DrMike

I'd really like to hear more about the optical mouse solution for headtracking. Can you give more details?

Flutter

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Hummmmm... I don't seem to recall ANYTHING about a so-called "IR LED device", so I can't comment on it. However, for progress to continue, it might be best to set the egos aside. My comments were directed to those who have the desire to further investigate and progress the technology.

Dr. Mike

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"...but the LED/gyro/etc. approach most people usually come up with has proven to be either too expensive, inaccurate, slow, bulky, etc., etc"

In what way is an "IR LED" not included in your comment?

In what way was your comment quoted above beneficial to those "who have the desire to further investigate and progress the technology"?

In what way was your comment not a broad trivialization of the efforts "to progress the technology" that have been attempted to date?

When you say "...has proven to be either too expensive, inaccurate, slow, bulky, etc., etc" , to whom has it been "proven?"

...now about that ego thing...

post-6-1079674397_thumb.jpg

Edited by Temporary Insanity

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I've closed this thread. Please take the ongoing discussion off-line. A purely technical discussion can continue in a new thread if needed.

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