
NOTE: This is only a short text version ment as a back-up in case the web page dies. I suggest that you use the link instead of this.


{PowerGlove FAQ}

Forward

Mattel PowerGlove FAQ version 0.3, [date]. 

Written by jet@well.sf.ca.us (j. eric townsend). 

Significant help and input from: 

Randy Shedden (randysh@microsoft.com), Linda Jacobson (lindaj@well.sf.ca.us),lots of people on the WELL, sci.virtual-worlds, and of course, the glove-list. 

The FAQ is still in a very rough state. Please send changes/adds/deletes to jet@well.sf.ca.us. 

All sorts of product names are probably trademark by the appropriate vendors. 

Comments in the form of [DO YOU UNDERSTAND THIS? -JET] are notes to myself, let me know if you have something to replace the note with. 

A current version of this file can be obtained from ~jet/public on the WELL or netcom. It will also be posted to USENET's sci.virtual-worlds, the WELL's vr conference and various mailing lists at sporadic intervals. 

If you are reading this via a World Wide Web (WWW) client here might be an interesting place. 

This is probably the last version of the PowerGlove-specific FAQ. It will probably be consumed by a HomeBrew VR FAQ, if things go well. (I recently (Jul 94) changed jobs. Much of my free time is consumed with work here at General Magic, Inc., making the world a safer place for personal communicators.) 

DISCLAIMER 

This document does not constitute an endorsement of any of the products, services or groups listed. 

It's not my fault if you get hurt, suffer loses, or get into trouble because of anything you read in this document. 

Please read the distribution restrictions in the Introduction. 



Introduction

This document assumes you have a basic familiarity with the terms and concepts related to virtual reality and also with USENET and the Internet with its related tools (telnet, ftp, mail). 

This document is written in TeXinfo, which means it is equally easy to read in source form or print out a nicely formatted copy. But wait, there's more! You could convince your site admin to install the powerglove faq into the emacs info database, and read it with emacs info or xinfo! If you don't want/can't info or print this document, you'll be able to read through with little, if any, difficulty. (For more information on texinfo, poke around in GNU emacs or ftp the texinfo package from /pub/gnu on prep.ai.mit.edu.) 

This document is copyrighted by J. Eric Townsend as documented on the opening pages and cover. Permission is given to non-profit corporations to redistribute this document in electronic or printed form as long as the document is distributed in its entirety. Permission is given to online services such as the WELL, Mindvox, and others to store this document for distribution to subscribers only if equal access to this document is provided to non-subscribers. (See the WELL's gopher server for an example, where this document can be accessed by gopher from systems the WELL does not own or control.) Permission is also given for USENET sites to redistribute this document to other USENET sites. 

Any for-profit distribution of this document is strictly prohibited, including CD-ROM compilations or inclusion in any other published work where a fee is charged. 



What is a PowerGlove?

In 1989 Mattel (yes, the toy company) introduced the PowerGlove, a handtracking device based on a glove. The PowerGlove was intended to work with the Nintendo Entertainment System (NES) in place of a regular controller. The PowerGlove can track motion of the glove in three-space, finger position, and has a set of buttons/switches on the top of the wrist. 

It has two modes "hires" and "lores". In "hires" mode, the PG reports the position in threespace, the roll, and configuration of fingers along with the SELECT, START, A, B, CENTER and ARROW CLUSTER switches (which are a part of the NES standard controller). In lores mode the glove reports position on the hand on the x and y axis and the buttons (thus emulating a NES controller completely and allowing one to use the glove with non-glove-specific games). 

The lores mode also allows the users to select one of fourteen (?) built-in programs that associate different sets of motions with the NES controller outputs of up/down/left/right/select/start/A/B. Each program also has its own translation of finger movements to control inputs. 



Why use a PowerGlove instead of <foo>glove

PowerGloves originally cost around $100, if you're lucky these days you can find them usually under $30 at a Toys R' Us on the remaindered rack. Most of the gloves on the shelves have been bought up, some by speculators. (I keep hearing rumors of people with 40-50 gloves in a closet who trickle them out a few at a time.) If you don't know what a Dataglove costs, you probably can't afford it. 



What are the big problems?

Several problems face you if you want to use a PowerGlove as a VR input device. These aren't technical problems (although there are those as well), mind you, but real-world problems. 

There is no official hardware or software support from Mattel, and the gloves are no longer being produced. Of course, there is no official hardware or software support from any third party companies either. 

Contact Nintendo for information if you like, but the person who answers the phone probably won't even know what a PowerGlove is. 

On the up side, everything you will use was probably written or designed by a fellow hacker. 



What are the technical problems?

The ultrasonic sensing is done with inexpensive microphones so it is difficult to place the sensing array directly on a computer monitor and get a clean signal. A somewhat common fix is to hang the sensing "array" on a wall that has a low ultrasonic reflection rate. People are using anything from towels to ultrasonic anechoic foam to dampen the noise. 

This detailed list of problems is from Randy Shedden: 





1.In order register your hand position, you must point your knuckles at the receiver array. It gets tiring holding your hand up for extended periods. 

2.The only information about hand orientation that get is rotation. (This is also called roll.) In flight technology, if you raise one wing while you lower the other, this is called rolling the plane. Ascribing this behavior to your hand, if you raise your little finger while lowering your thumb, this would also be called roll. If a plane moves it's nose to the left while the tail moves to the right, the plane is said to yaw. If you do the same thing with your hand, the ultrasonic transmitters would point away from the sensor array and you would lose all orientation information. If a plane lowers it's nose while the tail is raised, the plane is said to pitch. If you do the same thing with your hand, again you lose all orientation information. So, while the VPL DataGlove can track yawl, pitch and roll. The PG can only track roll (commonly called rotation). 

3.The information about how your hand is configured is not very accurate. As mentioned above, the material that covers the thumb and fingers has different electrical resistance depending on how much it is flexed. So, when you have a finger fully extended, the material is not flexed at all. When you have a finger fully clenched, the material is flexed to it's functional limits. This is expressed in terms of a degree of flexure (bentness) for each digit. This degree is one of 4 integer values. 

0 means the digit is fully extended. 

1 means the digit is a little bent 

2 means the digit is more bent than straight and 

3 means the digit is fully bent. 

4.For each digit, this resolution isn't very good. Aside from that, it is hard to flex the material to reproduce the desire degree of flexature. For instance, it is not a trivial matter to do a gesture that requires that the ring finger be at state 1 (a little bent). This digital (no pun intended) value is also hard to maintain once you have it, because moving the neighboring digits can have an effect on the flexure of the digit in question. Try bending your middle finger without also bending your ring finger. Additionally, Only the thumb and THREE of your fingers are tracked at all. For some reason, the PG doesn't keep track of your pinky. In comparison, the VPL DataGlove gives much better resolution on ALL of your digits and material (a small fiber optic cable) is much easier to use than the bulky PG material. 









Resources

If you are interested in the various mailing lists, you'll want to grab the canonical list of mailing lists from news.answers on USENET. (Or, failing that, from the author arielle@taronga.com. Don't bother her unless you need to, she's very busy and too nice to bother with trivial problems.) 



The PowerGlove mailing list

The PowerGlove mailing list is dead. (It fell on its head.) 

Modulo buying/selling used gloves, there was no glove-related traffic. I'll attempt to put *every* bit of knowledge in this and future versions of the FAQ. Once I've cleaned out the huge amount of crud from the archives, I'll p                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        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