Hi
This is pretty straight forward You need One serial over Bluetooth module 3 volt powered The ability to write some software in Android Or J2me Some understanding of the Bluetooth stack and serial ports
Knowledge of C++ , C other langauges associated with micro controllers A good understanding of embedded architecture
Lots of articles on the net re this
An electronic lock and some permanent power , Chargeable back up batteries
I dare say you have seen the automatic doors principle that works on magnetism
The Lock device works in a similar fashion to that of an ordinary serial port
The Users phone is sent an application via email or can download You would set this up via your own design statistics such that you can also send them a key which is an encrypted token if you like which would allow permanent access use only once access or what ever you decide to set
When the visitor comes into close contact with the lock the Bluetooth device then pairs with his / her mobile phone The token that you have sent to you pre agreed is transmitted to the lock
The key is the part that is transferred to the lock which you pre preprogram in also could be pre programmed into the lock via Bluetooth exactly the same as you would send a file to another pc or to a phone or Bluetooth enabled printer each time you organise for someone to come and visit your premises whilst unattended by yourself
This is transferred using a protocol we term as Bluetooth over serial port
See here for more details on the bluetooth stack
http://www.palowireless.com/bluearticles/stack.aspWe call this a virtual port and its so named because the Bluetooth stack simulates real hardware serial ports except over software and RF
After receiving the key the lock's Bluetooth transmitter/ receiver then decodes this key and opens the door Its actually quite easy to do
However pitfalls are You must have a manual override like any other lock otherwise if the unit fails or your locked out
Its actually a very good idea and can also be implemented using smart card technology as well which would be far safer
Similarly you could do exactly the same with wifi access and also sms access allowing you yourself more control as the owner but that’s money every time you use this facility meaning 30 pence per transaction ( in this case every time you unlock the door )
Its really not to far different from coded locks except that obviously Bluetooth is free and its done via RF Also similar to RFID same principle
Dangers if designing yourself you must encode the bluetooth stream using some type of encryption otherwise anyone could hack into bluetooth Another pitfall also Ypu key which you agree before hand i.e your password must also be encrypted
Those are the BewaresHence I like the idea, have thought on this many a time, but still prefer good old mechanical locks They are still always the best and by far the safest
The other beware is bluetooth can and is used to hack mobile phones Email is not safe and sms is not garanteed delivery service although it will get there but when !! in all apsects of the word so you could argue yes Make phone call when at the door Servers go down as well
Back up your application with hi tech security cameras You always want photos of who is entering , leaving your unattended premses ( Strongly adviseable ) Some people are not as trustworthy as you think Never assume they are
More importantly Theres a lot of nasty companies out there who will simply change thier mobile phones bluetooth stack or the implementation of this to attempt to controll the Market place The age old story of greed unfortunatley, otherwise I would have done this a long time ago make no mistake It is that clever
Also read the following ( More interest rather than anything else)
10 inventors who didnt get mega rich (typical this as well )
http://www.bbc.co.uk/news/magazine-23179103
