Prevent theft or missing of mobile phones

arunbabu3189how would be pairing wrist watch and a mobile phone using bluetooth and make the both to vibrate and siren when they are kept apart by a fixed distance be possible. this would help to prevent theft or missing of mobile phones.can anyone give idea for this project?i'm very much interested in this

This is a good idea! [Therefore moving it to a new thread!]

nice idea ..but the watch must be implemented with bluetooth which may be not possible ..

Why not possible friendster?

the battery of a watch is very low power use, and the transmission range will only be 10m, about 30ft.so if a thief gets mobile beyond the 30 feet then it may be useless..


To implement this we can use a high power cells Class Maximum Permitted Power
<a href="https://en.wikipedia.org/wiki/Milliwatt" target="_blank" rel="nofollow noopener noreferrer">Watt - Wikipedia</a>(<a href="https://en.wikipedia.org/wiki/DBm" target="_blank" rel="nofollow noopener noreferrer">dBm - Wikipedia</a>) Range
(approximate) Class 1 100 mW (20 dBm) ~100 meters Class 2 2.5 mW (4 dBm) ~10 meters Class 3 1 mW (0 dBm) ~1 meter

But that's what is supposed to make the watch vibrate isn't it?

The presence of the other one as detected by the watch and the mobile is the supposed normal condition

the absence is abnormal and that would raise an alarm. i.e if one gets out of range of the other both are supposed to raise an alarm(u dont know which might be stolen). This way u wont need much trasmission power(beyond 10m). If more than 10m apart, detection wont be possible and an alarm would be raised.

Wasn't that the whole concept??

Yep, I believe trigger by absence is the concept here. This is a pretty nifty idea.. will keep my eyes on it.

As an alternative, it might be possible to look at passive or semi-passive RFID. Atleast that might be easier to implement on a watch. Most of the power would come from the mobile too.

Just my 2 cents.

yes a nice idea, we can also start a timer in phone as soon as it goes out of range for say about 1 hr. If this phone and watch comes in range again the timer will stop. Main purpose of timer is we can initiate an event after 1 hr. for e.g we can place a deactivating circuit which will make phone useless.

just gave my thought, all comments welcome.

ashAs an alternative, it might be possible to look at passive or semi-passive RFID.

Yep, RFID will be a nice solution to the Thread.i had posted a detailed on RFID into SEMINAR TOPIC SECTION ,on my blog ,you can have a look .;-)
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How about an audible alarm & light? It would use a lot less power than vibration. Most watches/phones already have the capability of both so it would only require the proximity detector. Although I must admit ever since cell phones came out I no longer where a watch since my phone has a clock. Product research would be needed into that. I like the smart chip idea in the watch so that the phone will not operate.