Craig E. Steiner USA Signal Project "Stoplight bulb internal controller" Back to full resume | PDF version of this page Overview Developed the firmware that operates inside a LED-based stoplight bulb. The code detects when LEDs in the bulb are burning out and increases the brightness of the remaining LEDs. Also detects when the bulb is activated during the evening to auto-dim the LEDs to prevent the bulb from being blindingly bright at night. http://www.usasignal.com. Approach Perform A/D on the current being consumed by the LEDs of the bulb. If the current being consumed has fallen below a certain level (indicating LEDs burning out) then use the D/A to increase the current on the remaining LEDs so that the net brightness remains the same. If the total current selected by the D/A exceeds a certain level, self-kill the bulb to avoid the bulb actually burning up from the high current. Monitor the net brightness of the LEDs. If the brightness falls below a specified minimum level, self-kill the bulb so it gets replaced rather than operating at below-standard levels. Log changes made to the current in an attempt to maintain a constant brightness so that bulb failures can be analyzed to determine their source. Develop Windows to permit communication with the bulb, specifically to download bulb failure log information. Technology Microcontroller used was Philips P89LPC932. Microcontroller firmware developed in assembly language using Pinnacle 52 IDE. Windows application developed in Visual Basic 6.0. Craig Steiner's Role Sole designer and developer of the microcontroller firmware. Sole designer and developer of the Windows application. Contact Project Customer/Reference    Paul Calixto USA Signal, Inc. 15167 Business Ave Addison, TX 75001 Phone: 469-522-0820 Email: (Available upon request) Contact Craig Steiner Vault Information Services 8174 S. Holly PMB #272 Littleton, CO 80122 Phone: 303-439-0909 Email: csteiner@vaultbbs.com (C) Copyright 1997 - 2008 by Vault Information Services LLC. All Rights Reserved. Information provided "as-is" without warranty. Please see details. Contact us for usage and copy permission.