JVRSJ Vol.10 No.2 June, 2005

ラク楽実践 VR

日本ではあまり見かけないような気がするが，Web をみると Advanced Realtime Tracking GmbH( そのまんまの名前だ ) というドイツはミュンヘン近郊の会社らしく，フランホーファー研究所のサイトにも写真があるので，ヨーロッパでは流行中なのかもしれない．液晶シャッタ

ラク楽実践 VR

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眼鏡にも，偏光眼鏡にも，必ずといっていいほど，白い実のなった枝がついていて，スクリーンや画面の上方に赤外カメラがついている．
Advanced Realtime Tracking GmbH: http://www.ar-tracking.de/■コラム

お役立ち SHOP 情報（USA）

U.S.Store Introduction Report

Robert W.Lindeman
Computer Science Dept., Worcester Polytechnic Institute

Doing research in the field of VR often requires creative solutions to specific hardware problems. Usingthe "engineering method" of building several, incremental prototypes involving hardware and software,evaluating and improving the design with each iteration, can be aided by being able to quickly acquire basic
hardware components.
In the USA, there are several good online sources for ordering electronic parts of all kinds. Most places
offer different shipping options, including overnight shipping. In addition to parts, some places also carryequipment for outfitting a lab, such as variable power supplies, soldering irons, oscilloscopes, or staticmats. As with all shopping, it is a good idea to compare prices on different parts from different sources.
For example, when building our latest advanced prototype device, we purchased about 70% of the parts
from one vendor, 20% from another, and 10% from a third. This "comparison shopping" is an especiallygood idea for the most expensive parts of a given prototype, such as microcontrollers, clock crystals, andbreadboards. Because most places have a section on their Web sites where they list "Current Specials" orsomething similar, we can often reduce the (already low) cost of the parts significantly. These places also
have free printed catalogs you can order if you prefer. The main online shops that we use are Digi-Key Corp.
(www.digikey.com), Jameco Electronics (www.jameco.com), and All Electronics Corp. (www.allelectronics.com). Others exist, so it is best to search for others if you need some specialty parts not found at these places.
After a few design iterations using breadboards, it often becomes attractive to build a more-robust prototype
using a Printed Circuit Board (PCB). There are some good online options for creating prototype PCBs atvery reasonable prices. We have had great success with Advanced Circuits, Inc. (www.4pcb.com). The cost ofa single, two-layer PCB in quantities of one is around $35. Submission of the Gerber files (standard outputfrom PCB CAD packages) can be done online when the order is placed, thereby automating the entire
process. In addition, their telephone support is excellent, so it is possible to ensure the proper result.
In addition, a well-known chain of physical stores called RadioShack (www.radioshack.com), often carries
more-mainstream electronic parts. If there is a need to get a part more quickly than overnight, this may
be a good source, as you can just walk in and purchase. Located all throughout the US, the parts carried at
any one store varies, so it is always better to phone them first before visiting. We have found such parts as
rugged plastic boxes, gender changers, serial connectors, and audio cable. It is a bit more expensive thanordering from the Web or a catalog, but may be more convenient.
In closing, there are a number of surplus stores that often carry interesting items that may be of interestto VR researchers. One in particular, American Science & Surplus (www.sciplus.com), I have found to be agreat source for odd items, such as vibrating pager motors, LEDs, variable power supplies, and much more.
They have a very entertaining monthly catalog describing the items available each month. A creative person
can find many devices that inspire new ideas for use in VR by reading this catalog.

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