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Thursday, November 24, 2011

SigmaSecure (Happy Thanksgiving!)

That's right, we had a name change.  Our 2.009 electronic bike lock has made a lot of progress since I last posted.  It's sleeker, more secure, and the electronics are a lot more developed.  Plus, it's no longer just a CAD model! After several weeks of hard work, we got an actual working prototype.  Here are they key features:
  • One piece
  • Spring-loaded hinge design
  • Key-less entry
  • Wireless communication via XBee
  • Solenoid powered dead-bolt
  • Button activated
  • Backup key for mechanical override
The pictures from our technical review were taken down, but here's a Solidworks screenshot:

 I was in charge of electronics, so once we ditched RFID I decided to go with Xbee.  They turned out to be a very convenient solution with longer range capability.  By having an XBee on a low-power mode in a keyfob paired with an XBee in the lock, SigmaSecure can tell when you're nearby and unlock when you press the button. Even better, you can program XBee to signal when it is communicating with another XBee.  With this, we were able to trigger a transistor to allow our 9V battery to power the solenoid.  Since the XBee runs off about 3V, we simply used a voltage regulator to allow it to run off the 9V as well.

Next, we are looking into either using a latching solenoid or motor powered locking system to prevent some failures related to our spring-return solenoid.  Since the final presentation is only 3 weeks away, we are going to quickly make these last-minute changes so that we can end up with a polished product.

Now, back to the festivities at my girlfriends house...

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