This document describes a wireless sensing network that uses optical tags attached to physical objects to locate them. The tags are awakened by an AM-modulated light beam from a flashlight-like interrogator. When awakened, the tags produce a response that allows the object to be identified. The tags have a battery life of up to 10 years. The system could be used to locate items in libraries, DVD/CD stores, and factories for troubleshooting.

1. 2006_ 創新應用案例

2. 無線感測網路用於實體物品尋找
• Finding specific objects is important, especially in
digital age.
• CD’s, DVD’s, DV’s are scrawled onto
homogeneous containers.
• The simplest but stupid way to find particular file is
to insert and check it one by one.
• A label tag attached to these objects and can be
found by a flashlight.
• The flashlight awakens each tag by AM-modulated
beam, and tags produce appropriate response.
• the life span of a tag can be up to 10 years.
應用 明：說
IDEA FIND ：
Source: Hongshen Ma and Joseph A. Paradiso,
“The FindIT Flashlight: Responsive Tagging Based on
Optically Triggered Microprocessor Wakeup”, MIT Media Laboratory
• RFID is not affordable to the application because of its power
and radio coverage
• Many situations is suitable for finding an object physically,
such as library, record/DVD/VCD store, movie studio, and so
on.
• When trouble shooting in a factory, a mechanician may
highlight components interrogated.
• Charactering objects enables combinations of retrieval.

3. 營運模式
• 供應端 • 需求端
System integration
唱片行
製片廠
終端使用者
Mesh node
Sensor node
interrogator
software
OEM
應用服務商
電視公司
物件尋找系統
圖書館找書
公司檔案室
工業
Trouble shooting

4. 內容
• Microprocessor
– PIC12LC509A from Microchip
– When woken up, compares the
message from photo detector.
– Light LED if the message is correct
– Wake up within 22ms
• Photo detector
– Triggers the tag to wake up when hit by
interrogation beam.
– With High-pass filter to eliminate the
effects of ambient or 60Hz light
• Coded message transmitter
(interrogator)
– A diode laser
– A laser lens defocusing light to reduce
the pointing accuracy
– Laser can be replaced with LED
硬體