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I started this project (heh, have yet to finish it, but that is a whole 'nother story) to build an electric vehicle using bicycle parts, and decided to build the machine using a recumbent design. A couple of steel garage sale bikes, a bit of welding, and I had my frame. The seat was a fishing boat seat picked up from Walmart. Since I am planning on attaching an electric motor, there isn't any pedals or chain, but one could easily see how such a system could be attached in place of foot rest.

Do some googling on homemade recumbent bicycles - they are very easy to make, you don't even need to know how to weld or braze to put one together (one of the bents I saw out there was held together with bolts, screws and pipe clamps!). Go around on a bulk trash pickup day (if your city runs them) and you will find many, many bikes simply being thrown away. I used two bikes, a 26" (for the rear) 10 speed, and a 20" for the front fork assembly. Other tubing came from the same bikes as they were cut up. If you wanted a longer frame, steel electrical conduit could be substituted.

I have seen some weird homemade designs out there - including one made out of wood! I would imagine, if you had the skills, workspace, and a bit of money, you could design and build one using aluminum tubing and/or carbon fiber. You could probably JB-Weld and/or pop-rivet the thing together (provided you mixed the 2-part precisely to get the maximum strength bond).

So far, I have spent very little money on my project - I would wager you could build an equivalent steel framed bent (factoring in extra parts and such, not counting tool needs, of course) for under $200.00 (and that is probably too high an estimate). If you needed something lighter, it could be done, but it would take more scrounging and probably a trip to scrap metal yard to get some aluminum tubing cheap enough (unless you got lucky and someone was getting rid of an old aluminum mast antenna). Get the beater bikes and cut off/grind the bearings and such, attach them together using epoxy and kevlar string (think of "lashing an axe head" onto an handle, then liberally applying several coats of epoxy resin to the kevlar lashing).

Once again, do some googling on the subject - many people have successfully built homemade recumbent bicycles for very little or no money involved. You won't likely find a "how-to" guide, but you will find plenty of pictures, advice, and other documentation to get your ideas and creativity flowing toward building your own.

I hope you take this post to heart - good luck!

Right here...

Cheap VR

Huh????

This is a truely F-d up definition, if there EVER was one - case in point:

The Acer NT-150 Set-top Box

Let's see:

1. For use by one person at a time - check.
2. Uses a video display and keyboard - check (it has a wireless keyboard, and it hooks to your TV or to a SVGA monitor).
3. Contains an Intel x86 compatible microprocessor - check (it uses an AMD 586/133).

Hey - look! - it's a set-top box, too!!!

What idiot wrote this definition, anyhow?

Not my idea, but I have never seen an implementation of it, so I wrote a how-to a long while back on building it:

Cheap VR Issue 3

Basically, it works like a joypad, only larger, where you "lean" in the direction you want to "go".

BTW, don't bother emailing the address contained in the issue - it don't work anymore, instead, email to phoenixgarage addy...

First off, realize this:

If you want "pro" quality - expect to pay "pro" prices: ie, $1000.00 and up - this will be for a glove alone, mind you. 3D tracking tech will add to the cost, starting at around $1000.00 (give or take a few hundred) for magnetic tech (AC or DC pulsed), but since you say you want to use this with a PDA, I assume you won't need this, and only want flex sensors.

Will you need abduction sensing (ie, the fingers and thumb both flex, as well as move sideways, allowing for the lovely "Spock" gesture - this sideways motion is called "abduction")? If so, add a lot more to the cost of the glove - this kind of sensing is tough to do. It sounds like you might, if you want to do regular typing, and not "chording".

5DT sell good tech, but expensive - not really a great money-saver for a homebrew project. Hacking together a power-glove interface might be possible (I have done a simple parallel port one for my computer), but the power-glove can be difficult to find, though you might check Ebay (look for "Power Glove", note the space, as well as "Powerglove"). If you find one, you might try removing the flex sensors from the glove, and sewing them onto a lycra glove, for lighter weight and ease of use. The sensors are simple resistive flex sensors, you could probably build a simple interface for them instead of using the Powerglove's system, which is bulky. If you need abduction, you could place sensors between the fingers as well.

Also, go to my website. I have a lot of links that you might find useful - though they are a bit out of date, and I need to update them badly - very badly... In my Cheap VR Issue 2 I discuss how to build an optical style flex sensor glove cheaply, which you might find helpful.

Finally, think about this - there was (is?) a company out there that sold a glove that had simple metal bits sewn in, that when touched together completed circuits (I think it was called the Pinch Glove or somthing). This kind of system would be easy to homebrew - just don't try to sell it or claim it as your own tech, etc (you know, the whole IP bit). Simple buttons or rivets could be but on the tips of the fingers, wires soldered on, some added to the palm of the hand - add some switch debouncing, and a simple custom programmed PIC or Basic Stamp, connected to a serial interface (Max-232) - and there you go - instant gesture recognition system!

Finally, a word about your statement:

So that I can hit a real-size virtual keyboard in air and type faster. Who really needs to see the buttons?

Actually, try "typing" for a length of time with you arm in the air, and you will see why doing any "virtual" movement hasn't really caught on:

It is tiring.

Indeed, the best way to type virtually, so that you wouldn't tire, would be to simply keep the arms in a "rest" position, hanging at the side of your body.

One reason this tends to be tiring is that there is nothing to work against, like on a real keyboard, or in the case of VR manipulation of objects; a real object that has weight. We, as humans, like to rest our body parts as we work, which is why not many of us work for long periods standing all the time (and which is why being a store cashier really sucks). It is why we have chairs, etc.

I suggest you look into chording keyboard systems, and apply this tech to a "pinch" style glove - such a "keyboard" would actually be very useful in a real world "wearable computing" situation...

Want to know more about homebrew VR (and in turn, hooking up the Powerglove, and building your own glove device) than you can stand?

Click here...

Worldcom - Generation Duh!

How did they get around the VPL/Mattell patents?

For those that don't know, VPL made the VPL DataGlove, back in the early 90's. They also worked with Mattel to create the Nintendo PowerGlove. Unfortunately, their patent on using a glove-type input device kinda locked everything up - very few ways around the patent have ever been found. Most alternative glove input methods have been either klunky (one is a very intricate mechanical waldo like device that is fitted to the hand and uses hall-effect sensors to gauge the angle of the joints - very accurrate, but also hard to put on and take off, and expensive - not that the VPL DataGlove was cheap), or focused on other methods (such as detecting fingers touching together, rather than finger angles).

The only thing I can figure is that they either bought the patent rights, or are licensing them. Either way, I would much rather see a glove based on the fiber optic technology of VPL, rather than the flexible stress sensors the PowerGlove uses (and it does look like that is what they are using)...

If anyone wants more info on glove devices, etc for VR and such (PowerGlove interfacing to PC, etc), check out my website...

Worldcom - Generation Duh!

I am sure not going to win any points for this POV, but I think these displays are DOA.

A limited FOV, the need to not move the head too much, and a high price tag - effectively puts it out of reach of consumers, and should even make the IS department of any company who might have a need for such a display to do a double-take.

One person here mentioned a CAVE solution, or an ImmersaDesk-style system. Such systems would be better for many of the same apps, but both are still quite pricey. This same poster thinks that such systems will become affordable for the home user (I imagine he was speaking of the ImmerasDesk system) in the near future, coming in at around $500.00! This person has never priced LCD projectors (and I think high-end CAVE systems use CRT projector systems, just to get the high refresh rates needed for the stereo shutter glasses) apparently - prices for these devices, which would be an intregral part of any such system - haven't come down much in the past 10 years. Indeed, what seems to be apparent is rather than keeping the older tech around from the early 90's (which would be more than adequate for home projector use), and charging less - projector companies tend to dump it, and only sell the latest, thus keeping prices high (an ok projector will run you a minimum of around $1000 - used, you might get away with $800).

So, what does that leave for the average consumer? CAVE/ImmersaDesk systems are out and this DTI tech is out. Both mainly from a cost standpoint - prices that are not likely to come down at all in the near future for either system (barring some breakthrough in display tech - and even then the price will be high because it is *NEW* and *EXCITING*).

Only two possible affordable solutions - Shutter Glasses, and HMD's.

Shutter glasses are available now, and supported by several graphics cards, and they are cheap - however, while they allow more freedom of movement of the head, they still only have a limited FOV - due to the monitor. They are, and will continue to be, the choice for most people - only due to cost and ease of use.

HMD's are still rather pricey - but one can get an HMD today for around $1000 dollars that works quite well. Still, this is rather expensive for most gamers, who have already shelled out this much and more for their system likely - and don't have much left over for exciting 3D. What to do, what to do...

Homebrew, anyone? Why has EVERYONE (ok, that's an exageration - but not by much) forgotten about homebrew VR? Once, way back in the early 90's - if we didn't have a custom 3D display tech, we built it ourselves, using cheap (and cheaper today!) Casio hand-held TVs and Fresnel lenses, cobbled together in a plastic frame. The PowerGlove allowed us to reach into our worlds, and a lightweight boom mounted system allowed us to look around (some of us got adventurous, and used strings, LED's, ultrasonics ripped from PG systems, and other tricks for tracking - but the boom arm was the most accurate).

Today, homebrew VR has all but died - a few people still play the game, but most went on to other things. But look at what is available! We have free, open-source, GPL'd display engines! Low, low cost HMDs on the used market (one can pick up a used Forte VFX-1 for about $400 on eBay - Victormaxx Stuntmasters can be had for around $50). One could buy a couple of StuntMasters and home-brew their own HMD, with good res and a 60 degree+ FOV (the point of immersion), for under $300. We have fast, low cost computers and extreme 3D cards only dreamed about by the pioneers of the early 90's. Heck, one can run Rend386 or Avril on a normal PC of today, rendering standard VGA, and see frame rates well over 150 FPS. The code to both of these tools is available, and other code is available to do similar tasks under Linux and other OS's - using today's graphics cards...

What has happened? Why aren't we satisfying the urge to explore our own 3D worlds?

In a way, we are - witness things like Q3A and UT - both are networked virtual environments - the only thing lacking is full immersion, with full tracking. I can't understand why these players aren't clammoring for a fully immersed experience, or at least why some of them haven't built their own HMD systems, or why they would rather sit in front of a monitor playing a game, rather than being *in* the game. Q3A and UT offer the possibility of extreme VE immersion only dreamed of in the Rend386 days - yet donning a homebrew HMD, reaching out with a PowerGlove, and catching a spinning bannana is still something that neither UT or Q3A can quite match...

On a final note I would like to offer a link to my website, where I am trying to inform the public about homebrew VR, and today's possibilities:

PhoenixGarage.ORG

All you have said is very true - but one thing you left out (or maybe only hinted about, if you read between the lines, so to speak), is one of the main reason motion sickness occurs:

One set of senses are telling you one thing, while another is seeing (or perceiving, perhaps in the wrong way) another.

Case in point, for the poster: He is obviously well immersed in the game, but most of his body is motionless - however, his eyes are perceiving that he is in motion. These two conflicting inputs (that of the eyes seeing motion, but his inner ear telling him he's not moving) help cause the motion sickness he experiences.

How to help? Don't get immersed - have a frame of reference for your eyes that show them you aren't moving as well. Either sit farther away from your monitor, so that you see the edge of the screen, use a smaller monitor, or run the game in a window.

A similar way to get sick is to ride an amusement park ride with your eyes closed in the late evening. Kinda the reverse of what the poster is experiencing.

You talked about lag. In a fully immersed setup (High quality, 60 degree FOV or greater HMD, etc), lag can cause severe difference in inputs, if the lag is large enough. Say the screen is updating as you turn your head left, then you quickly turn your head to the right. The screen may still display the images of what you were doing when you were turning your head to the left, as you are really turning your head to the right (the Virtuality 1000 game system was notorious for this) - time to spew. Another problem with fully immersed systems can be sensor calibration - this would help cause motion sickness, either by say - an electrolic tilt sensor "sloshing" after physical movement has stopped - and hence displaying to the user they are still moving, or by the sensor being out of alignment with the users actual position - maybe in an extreme case giving the user the image of him looking up, when he is trying to look straight ahead.

From my personal experience, I don't have a problem with immersed or semi-immersed virtual environments, even ones with bad lag. Maybe I have just adjusted, or for some other reason it doesn't bother me. What is strange though, is that I find reading while in an automobile (as the passenger, of course) makes me feel a little queasy - at least enough where I don't like to do it...strange...

Here is a link to a paper done on simulator sickness for the U.S. Army Research Institute, by Eugenia M. Kolasinski:

Simulator Sickness in Virtual Environments