Head worn VR displays and
Stereography for monitors in general
Using lenticular lenses
Using parallax blocking masks
One of several methods of using cardboard boxes:
Flatscreens can be used for head worn equipment.
A screenful for this adapter:
The above images can also be seen without a cardboard adapter by crossing your eyes at them
until you see 3 pictures horizontally, and then focus on the middle one. It's hard for some people
without an adapter though. Also, an improved adapter splits the screen in half with two wide images,
one above the other. That is much better, giving a natural panoramic view (some optics required,
and it doesn't apply to these pictures, above.)
A single flatscreen may be used for any VR goggle system, and reducing lenses are recommended
3D shutter glasses are available for high refresh rate monitors, and these are very simple to drive also,
but flatscreens are even less likely to refresh fast enough than tubes. (140 Hz rate recommended).
Local Positioning Systems
The "North Pole" or "Lighthouse"
(what should we call this one?)
In the design of a Sonarvision project, a
benchmark was necessary
so that a robotic explorer could map the terrain, the topography of a
murky lake, in that case. This single positioning fixing station is
an active transmitter which provides a receiver with an indication
of it's relative position. This device is simple and useful in navigating
physical, arbitrary, and virtual landscapes. This is how it works:
Stacked on the Pole, there is a small omnidirectional speaker facing downward
and at a cone. Also there is an infrared strobe that flashes in synchronization
with sharp pulses that are generated by the speaker. These pulses are so
sharp that they may not be audible, except that they cause other parts of
the pole to resonate. The distance from the pole is calculated by the difference
in arrival time between the inaudible sound and the flash of invisible light,
by a binary counter which is reset by the light, and latched by the sound.
Also, between pulses of light and sound there is a rotating cylinder with
a vertical opening on one side, and an infrared light source constantly on
inside it. The vertical crack in the cylinder, when it is facing "north", triggers
the distance mechanism to emit it's light and sound pulses. By counting the
time between the sharp infrared pulse and the peak of the one received as
the rotating crack faces you, you determine the direction of yourself relative
to the Pole. The maximum distance is limited by the range of the light and sound,
and affected by the rotation speed of the Lighthouse. 1 RPM gives simple
1100 feet range, and a 1 second sampling rate.
This system can be used more effectively as part of a Head Worn 3D display
to determine your position in a room many times a second. The receiver on the
"helmet" would be simple, but provide only distance and direction information.
What more is needed is information about the direction you are facing; a compass
can provide that information... and how high your point of view is above the floor
(which will change if you duck). While writing this I suddenly realized that measuring
tilt would be a good idea also, but at the moment I have not thought of a simple
If a VR room uses a lot of radio signals it may be a good idea to shield it with
screen to avoid interference. A head display could "easily" be driven wirelessly
with 3 TV channels for separate high definition RGB 3D video.
The light pen/magic wand 3D GUI.
A pulse oscillator generating 40KHz IR pulses
AND sound pulses is compatible with
common IR receiver modules and provides the same distance information that the
Lighthouse/Pole does. In a VR room, four corners may have infrared receivers and
small electret microphones to receive this distance information and accurately determine
the position of the light pen. The light pen is turned on by it's "mouseclick" button.
Holding down the button is used for drawing in VR. The smaller dimensions of a typical
room allows a faster sampling rate: 1 millisecond for every foot of room length (3ms/m).
Centimeter resolution can be expected. Logical output of this device should be ZYX
and code should be less than 1Kilobyte. Using radio instead of IR will eliminate the
need for multiple (IR) receivers.
The recommended sound format for head worn VR equipment is headphones with
sound that was sampled using a dummy head with microphones inside of it's realistic
ear lobes. This is the natural physical encoding for the most realistic 3D sound.
(Also: when sounds are heard underwater, this fails, and a correction would be to
use very large artificial earlobes in the sampling/recording process. The speed of
sound in water is variable but averages 1 mile per second; in air, 1/5 mile per second.)
There is a complicated problem with this when you are free to walk around the VR room,
and in that case at this point "cheesing out" with multiple speakers may be the simplest solution.
Simple options are : Infrared, Ultrasonic, Radio. Radio is easy within room range.
Clock crystals generate frequencies for transmitting- the 4 pin kind input 5 volts and output RF.
The tuners from old VCRs give wideband reception for video, data, and sound,
easily exceeding many "wide band width" standards; many need only power and voltage-controlled
frequency selection as input; NTSC tuners may cover 50-800 Mhz.
and output separate or combined baseband audio, video, and color signals (which are not strictly
bound to those kinds of signals. The "video" signal has a 3 MHz minimum bandwidth).
Radio Interference is not legal so using shielding may be necessary.
The simplest way to get lots of data onto a wire is just put current into it, turning it on and off as
fast as you can. Coaxial wire is technically the most broadband type, and using it is a good idea
because it is shielded and doesn't cause interference, which is always likely when things are
turned on (1) and off(0) very fast. The simplest way of coding data is like morse code, using
dots and dashes for 0 and 1, and links used that way are not speed critical.
The simplest way to have a network is to have one cable connected to everything, and whatever
wants to talk has the option of first saying what it wants to talk to, then sending data as fast as
it can or wants to. Then it may say it's done.
If the sender does not specify a receiver, then all receivers will have to look at the data and see
if it can use it. If not, then it ignores the data. That might waste processing time for the receivers,
so it's better to briefly address the indended receiver and then send raw data to it and then say finished.
An example of the simplest data network in common use that I am aware of is MIDI. It works similar to as
described above, with moderate bandwidth (32.5Kbps), and only in one direction (from the sequencer to the
Recommended standard simple protocols for networking are:
CAN - Controller Area Network (very simple streaming bidirectional and most similar to Dreamatron protocol)
X.25 - A packet protocol much simpler than TCP/IP
Fiber networks that I have seen do not live up to expectations. Technically they should be able to
handle 1000 GHz but in experimentation I could not get beyond 2MHz and rarely see 10Mhz bandwidth
on them. Coaxial cable has had average fiber beat for decades, and amateur 100Mhz is trivial.
These things aren't all necessary for any project, nor are they the simplest or only ways to do them.