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Object Finder

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This essay does not describe an existing computer program, just one that should exist. This essay is about a suggested student project in Java programming. This essay gives a rough overview of how it might work. I have no source, object, specifications, file layouts or anything else useful to implementing this project. Everything I have prepared to help you is right here.

This project outline is not like the artificial, tidy little problems you are spoon-fed in school, when all the facts you need are included, nothing extraneous is mentioned, the answer is fully specified, along with hints to nudge you toward a single expected canonical solution. This project is much more like the real world of messy problems where it is up to you to fully the define the end point, or a series of ever more difficult versions of this project and research the information yourself to solve them.

Everything I have to say to help you with this project is written below. I am not prepared to help you implement it; or give you any additional materials. I have too many other projects of my own.

Though I am a programmer by profession, I don’t do people’s homework for them. That just robs them of an education.

You have my full permission to implement this project in any way you please and to keep all the profits from your endeavour.

Please do not email me about this project without reading the disclaimer above.

Introduction WiFi Approach
Alternate for Static Objects Commercial Finders
BlueTooth Approach GPS Shopping
RFID Approach Summary
GPS Approach Links


I wrote this essay circa 1996, but at some point it quietly disappeared I decided to rewrite it rather than dig through all the backups. Since that time there have been a number of commercial implementations.

The basic idea is you lose your keys, glasses, wallet, TV remote, personal recorder, calculator, ruler… You need something to help you home in on the lost object. You key in the name or number of that lost object and it gives you some idea of the direction to look. A tag on the object itself might beep or flash.

The most difficult application would be to invent something to find eyeglasses. Whatever you attach to them has to be small, light and unobtrusive. Eyeglasses are also the most commonly misplaced object. They are also especially hard to find when you don’t have your glasses to see to find them.

Alternate for Static Objects

A related problem is to help you find books, cooking equipment, spices, food, camping equipment etc. that you stored away carefully, but forgot where. You put RFID (Radio Frequency Identification) tags on each item and record where you put them when you stored them away. You could label your bookshelves and storage boxes and kitchen cabinets with a Dymo label. When you need to find something, the computer tells you the Dymo label name and the RFID. You can then rapidly go to the right bin and scan by RFID.

Some of this material might be stored in a storage locker or garage. The advantage of this approach is it handles thousands of times, however, it does not handle items that have been moved from their official place.

BlueTooth Approach

Another approach is to use tiny BlueTooth transmitters and Blue Tooth smartphones with special software as the locator. There are three classes of BlueTooth 1: range 100 meters, 2: range 10 meters and 3: range = 1 meter. Obviously class 3 will not work. Apple iPhones are class 2. Class 1 would take too much power. For example, the StickNFind system requires a iPhone 4S and above, iPad 3 and above (including iPad Mini and iPad Air), The New iPod Touch (5th generation and above), Samsung Galaxy S3 (Amazon Simple Storage Service) and above, Samsung Note II and above and any device running Android 4.3 or 4.4. A cheap Android phone is in the order of $85.

RFID Approach

RFID tags cost about $0.50 USD each. They are small, light and flexible. They could be attached to glasses and clothing. However, I have not seen any RFID-based finders. Perhaps the sensor unit is too expensive. It must put out sufficient power to be reflected back since the tags have no power of their own. RFID technology allows cheap, compact tags, but not sound or flashing. RFID does not require batteries in the tags.

I have written several RFID companies. None returned my queries, not even a perfunctory dismissal.

One person suggested using a USB (Universal Serial Bus) smart card reader. However, its range is perhaps only 8 cm (3.15 in). Further, it will tell you the number on the card, but not the direction to it.

An RFID hobbyist told me to give up on RFID because it does not have enough range. You have have to be almost on top of the tag before you could detect it.

GPS (Global Positioning System) Approach

You might also use it to help you find a parked car. With GPS, it can tell you where it is. It might work by having a hidden GPS unity in your car, or it may be a hand held unit that remembers where you car was and guides you back to it via GPS.

The Tile App has a feature to help find stolen objects as well. It works by commandeering all the finders in your area to also search for the stolen item the next time they are used. This would only work if you had multiple Tile App users per block.

WiFi (Wireless Fidelity) Approach

Before you dismiss me as nuts, I am not suggesting putting a full blown Ethernet WiFi receiver inside every device that needs to be tracked. For the forseeble future that would be too costly and too bulky, however, the cost and size are shrinking rapidly.

What I am suggesting is putting ordinary finder technology inside the WiFi router box. It need have absolutely nothing to with WiFi. This is just where you house it and how you buy it, as a feature, not a device. I am further suggesting building in receiver technology at the factory inside easily lost objects such as digital recorders, remotes, calculators, portable GPS units, cellphones, eBook readers, DVD (Digital Video Disc) Cases, eyeglasses etc.

Why bother?

How might it work? It would work much like other finders, except that its has a big screen to communicate with the user to select what is lost (possibly with photo) and to tell the user where it is (possibly with a map of the home) or with more meaningful words like under the couch in the den.

Commercial Finders

There are now hundreds of finder models. Most come from China. Some are as cheap as a dollar each. Most are designed for finding keys. The fob is too big to attach to glasses or a TV remote or a calculator. The cheapest ones work by whistling.

The trouble with ones where the keys make a noise is they get triggered by mistake all the time.

Commercial Finders
Vendor Price Notes
DX $15 for 4 receivers. Free shipping to Canada and USA. Specialised for keys. Not suitable for glasses. Press one of four buttons to trigger a beeper on the keys. Range 20 metres (21.87 yards)
The Tile App $19 per year per receiver Uses Apple IOS device as the finder. Receivers must be replaced annually. Receivers are rather large about the size a scrabble tile so you could not attach one to your glasses, but they are still smaller the competition designed only for finding keys.
FOFA $25 per pair FOFA (Find One Find All). To find glasses they use a chain than goes between the temples with a fob in the middle. Each fob acts as both a finder and receiver. You press a button 1 to 6 to select which device you want to find. Each fob contains a loud beeper. The fobs are not waterproof.
Sharper Image $17 for a finder and two receivers. US only The fob you attach to your keys look like buttons. They are smaller than usual. They have a range of 12.19 metres (13.33 yards).
EyeWhere $30 for finder/receiver pair. Specialised just to find one pair of glasses. Works by clipping a rather large fob to the temple of the glasses. The Borg would love them.
Search for key finders Search for fob-style finders Search for sticker-style finders

GPS Shopping

electronic product image recommend electronic⇒Bushnell Back Track Original G2 Bk/Orto electronic home
asin B006U3ZJAM
dim 7.49 × 8.99 × 1.90 cm
2.95 × 3.54 × 0¾ in
This product is not in stock at any of the Amazon stores. This little unit contains a GPS receiver, but contains no maps and has only the most rudimentary screen. It runs off two AAA batteries. There are variants in dozens of shapes and colours, most more expensive. This model comes in black, orange and silver. What possible use is it? You put in on your keychain and when you park your car you press a button to tell the unit Remember this spot. Then later, when you want to find your car, you press another button and an arrow appears that keeps pointing at where your car is (or at the next intermediate point on the way to your car.) If you use it in the woods, it will guide you back to where you started your hike. You can use it any time you need to get back to some starting place. You could use at an exposition to find your way back to the entrance. You could use it to find your way back to your hotel in Japan. Its bigger brothers behave like hiking GPSes without the maps. Specs.
American flag Canadian flag
Canadian flag Canadian flag
German flag Canadian flag
Spanish flag Canadian flag
French flag Canadian flag
Italian flag Canadian flag
UK flag American flag
India flag American flag
UN flag other stores American flag American flag American flag
Greyed out stores probably do not have the item in stock
electronic product image recommend electronic⇒GPS Tracking Device, BayTracker BT-2000 RealTime Spy Tracking Deviceto electronic home
asin B00LWE49GO
This device is not for navigating but for spying. It quite small — easy to conceal. You must set up a GSM/SIM data cellphone account for it and pay the monthly texting fees. It sends its position in periodically over the cellphone network. You could use it to locate your vehicle if it is stolen. You could use it to track where your teenage children drove and how fast. You could put it in a briefcase to track its whereabouts. You could use it to track the whereabouts of your pets, equipment, Alzheimer’s patients… It is battery powered, but it can also be hooked up to a car battery. It has a hidden microphone for covert operations. Basically it is a remote-controlled phone. 60-day standby battery.
American flag Canadian flag
Canadian flag Canadian flag
German flag Canadian flag
Spanish flag Canadian flag
French flag Canadian flag
Italian flag Canadian flag
UK flag American flag
India flag American flag
UN flag other stores American flag American flag American flag
Greyed out stores probably do not have the item in stock


For finding keys, there are hundreds of inexpensive solutions. Just pick one that looks nice. For finding other things like TV Remotes, you need a small, flat and stickable receiver. All but one of the schemes I found with small receivers require a BlueTooth phone to run the finder application. If you don’t have one already, that is a fair extra expense. Though perhaps I should look into the cost of a second hand one without a connection plan.

3M RFID finder manual
Allbe1: multipurpose sensor
Arduino With Bluetooth
Chipolo: ultra thin BlueTooth finder
Electronic Leash
StickNFind: tiny fobs BlueTooth finder
TrackR: bluetooth finder combined with crowdsource GPS. Requires GPS cellphone
WalletTracker: BlueTooth finder, 100 foot range, chaotic pricing, many models, read Amazon reviews

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