USB StatusBox

A USB status indicator is constructed from some surplus telephone displays (Lite-On ST2225A), an arduino clone, and a photo display box. This is a work in progress.

Early testing of the prototype StatusBox with 1 boarduino and 4 displays.


Current StatusBox with 1 freeduino and displays mounted in a photo box. (Lid is off.)

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Current status:

• Completed the case top.
• Wrote the first display application. Displays transaction counts from a production imaging service at work.
• StatusBox appeared in the Make Magazine blog here.
• Fellow Make Magazine blog reader Tim Watson emailed to say he had built a couple of very similar displays. Check out his server monitor and weather station (also on the make blog).

Last Updated: October 11th, 2008

Construction

• StatusBox picture/video set on Flickr.

Arduino Code

The arduino code was designed to handle n display units. In this case 4 displays are used. The code allows each display to be addressed individually but also supports arbitrary scrolling between displays. The commands are sent to the arduino using my radio protocol. This allows the unit to be used with a USB connection or a simple radio connection without changing the software.

The commands currently implemented by the StatusBox (sent in 'Message Data' above) are shown below. There are two sets of commands, standard commands (UpperCase) which use the built in alpha and number fonts, and raw commands which don't use the fonts. The alpha font is currently 128 ascii characters. The number font is 16 Hex digits plus another 16 characters for a total of 36 characters.

The lights in the displays are organized in 5 banks which must be continously updated to keep the displays lit. The displays share common latch and clock lines but each is given its own data line. No additional multiplexing or external parts are needed!

Ardunio Code: available here.

Dotnet Code

I wrote a quick utility to test the arduino code by sending commands from a Windows form application. The application appears below.

As part of the first StatusBox application I wrote an StatusBox IO library that wraps the serial (USB) communications. The library provides a simple functional API.

Dotnet Code:

• Test Application.
• IO Wrapper.

Wiring

The wiring schematic for the StatusBox is shown below. Each display has its own data line (D4 through D7) but the clock, reset, power and ground lines are shared and wired in daisy-chain fashion. Only the arduino clone and the 4 displays are used, there are no other components. Power is supplied by the arduino USB connection.

Sources

I stumbled across these surplus telephone displays and how to use them on the Serial Wombat website. I also used the RobotRoom website. Many thanks to my fellow experimenters for sharing!

• The "Boarduino" used in the prototype can be found at Lady Ada.
• The "Freeduino" used in the final version can be found NKC Electronics.
• The displays were available from All Electronics for $1 (how can you go wrong?) but they're no longer in stock. I found some more for $6 at Excess Solutions.
• The photo display box was purchased at Hobby Lobby. They have many photo boxes suitable for repurposing as cases. The frame I used was $19.95 but was on sale for half price.

This material is Copyright © 2008 Craig Buchanan. All rights reserved. This page may be freely linked to.
Please send comments or questions to mailto: buchananc@acm.org.