TrafficStop

view the flickr photo gallery : read the build journal : email the creator

I retrofitted this generic “Blinking Traffic Light” with a USB module and wrote a simple Mac application to monitor my computer usage and reflect the results in by changing the stoplight.

This project was born out of the frustration after being constanty interrupted by people who could not tell that I was already busy. The alpha version of the software detects the number of running applications on the computer using Cocoa’s NSDistributedNotificationCenter and updates the light based on a user-defined threshold.

The application resides in the System-wide status bar and the icon is updated each time the light changes to reflect the current color of the light. Future versions of the software will include the ability to monitor CPU usage, unread email, and more.

This project is not complete by any means. That said, I have dozens of other projects that are nagging at the back of my mind that I would like to get started on. If you think this project is good, and you would like to see more: updated software, source code, build instructions, schematics, custom PCB’s etc. Please feel free to leave a comment below, on the Flickr photo gallery, or email me directly. Your input, suggestions, and encouragement will help push this project further!

Bill of Materials

I have been overwhelmed with the number of requests for additional information on building TrafficStop, and I have promised a number of you that I would make a schematic and printed circuit board available online very soon. Still, many people are anxious to build one of their own.

Below is a list of the items you would need to build a USB controlled traffic signal of your own, as shown in the photographs. I had thus-far refrained from making this information public because the incurred cost is a bit high for such a simple project. This is due to the extraneous components that make up the individual kits.

If money isn’t a concern for you, peep the Bill of Materials below. Otherwise check back soon for the official schematics and PCB layout diagrams.

If you know your way around a schematic you can shave $18 off the cost of the USB Interface Board by buying the USB chip and minimum parts kit without the interface board.

• Random Flashing Traffic Light $21.99
  
• USB Interface Board $28.95
• OP-51 LED to lightbulb relay board** $18.99

This device is rated for Japanese 100VAC current, I would suggest finding a 117V equivalent.

Software

The (very alpha) software is now available for download via googlecode.

There is no official releast download at this point. The repository is presently geared toward developers who would like to continue to improve TrafficStop. If you have a subversion client installed on your computer, you can get the latest code by typing the following from the command prompt:

Mac users:

• svn checkout http://trafficstop.googlecode.com/svn/trunk/mac .

Windows .NET users:

• svn checkout http://trafficstop.googlecode.com/svn/trunk/win .

The schematics and PCB layout: (coming soon)

• svn checkout http://trafficstop.googlecode.com/svn/trunk/sch .

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