Paul's Passcode Contest Entry: Difference between revisions

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=== Contributors ===
=== Contributors ===
* [[User:trailerphi|TP]] - Helped with how to use transistors
* [[User:Traylerphi|TP]] - Helped with how to use transistors
* [[User:Craig|Craig]] - Assisted by being someone to bounce ideas off of.
* [[User:Craig|Craig]] - Assisted by being someone to bounce ideas off of.

Revision as of 16:11, 9 September 2009



This is my entry into the Passcode contest, I am mostly doing this for fun and I doubt it will have any practical application in the end. Essentially I am creating a kind of digital combination lock with a VFD display. Part of the display is going to revolve around a 3v analog meter. It essentially moves a needle up and down (or depending on how it is oriented, left and right) as the voltage varies from 0 to 3v. By wiring up a potentiometer to an analog input on my arduino and to the 3v meter, I can have a knob that moves the needle over a row of numbers and then when the user pushes a button I can record the number associated with the value of the potentiometer.

That is the first half of the lock, which is really simple and straightforward. To make it a little more complex and give it a bit of something to show off (and truthfully to play with my VFD) I am going to see if I can work out a way that when you select a number with the Potentiometer / button / 3v meter setup, it will display the numbers you have selected, separated by periods.

So an example operation:

  1. Turn potentiometer to 1
  2. Press the "Select" button
  3. The number 1 appears on the VFD followed by a period.
  4. Press the clear button, the number 1 goes away.
  5. Turn the potentiometer to 13 & select
  6. The number 13 appears on the VFD followed by a period.
  7. Turn to 21 & select
  8. VFD displays: 13.21
  9. go to 4 and... VFD: 13.21.4

Maybe at some point I could incorpate other features into the lock to make it more of a game, but for now this is my current plan.

Project Manager



  • TP - Helped with how to use transistors
  • Craig - Assisted by being someone to bounce ideas off of.

Project Status

A quick summary of the project's current status. The widget has been programmed and the case is being painted. Etc.

Parts involved with this entry

  • Arduino w/ Protoshield
  • Itron FG95H1 VFD
    • I need at least 7x PNP transisters that can withstand 12v current coming from an ATX power supply. I picked up some cheap radioshack ones, one burnt out and another burnt my finger... I think I need something I can attach a heat sink too.
  • Analog 3v Meter
  • Potentiometer
  • Push Button


  • Find some better PNP transistors that I can either attach a heatsink too, or have a better current rating than my current ones.
  • Print out a new background for the analog 3v meter.

Project Updates

None Yet