Change History

Change Date Description
06-18-2019 Updated RPi photos page with image of yard turnout servos and trackage diagram.
06-11-2019 Schematics updated; ServoInterconnect and Mainboard sheets. Changed two connectors for existing layout wiring. T18/T23 and T22/T19 changed to T18/T22 and T23/T19. Spare servo ports T28/T29 assigned to turntable lead track turnouts.
06-08-2019 Added links to YouTube videos on RPi photos page. Clips show operation of grade crossings, semaphore, and turnouts when run using RPi test code.
06-04-2019 Updated RPi photos page with images and adjustment procedures for semaphore and turnout servos. Schematics updated. Servo interconnect and Mainboard, semaphore lamp resistor.
05-28-2019 Schematics updated; GradeCrossing and Keypad sheets. Control signals for sound modules removed from shift register and assigned dedicated bits on the PP2 GPIO expander hat. These sound module control signals are then passed through a ULN2803a. This serves to invert the control signal, the sound module inputs are active low (0), and also to provide pull up to prevent stray sound activation during RPi startup and shutdown.
05-23-2019 Schematics updated; Mainboard and Keypad sheets. +12 volt added for ITTC sound modules and existing holdover position panel LEDs. These panel LEDs include an integral resistor for 12 volt operation. Added ULN2803a on Keypad sheet to drive the panel LEDs. Added 12 volt power module, J4 connector, and capacitors to Mainboard sheet.
05-20-2019 External board schematics updated, added resistors. Rpi photo page updated to show gate servo clevis detail, gate servo mounting, grade crossing external boards, and completed mainboard.
05-01-2019 Code updated to See DnB_RpiCode for details. Schematics updated for sensor related wiring changes; semaphore lamp drive, external boards interconnect page.
04-09-2019 Code updated to See DnB_RpiCode for details. Updates to schematics for shutdown button and general layout.
02-02-2019 Updated RpiPhoto page with images showing block detector circuits.
01-30-2019 Updates to SensorInterconnect and SupportCircuit schematics to clairify connector/transformer wiring.
01-02-2019 Updates to Mainboard and SupportCircuit schematics for use of external amp/speaker unit.
12-30-2018 Code updated to See DnB_RpiCode for details.
12-19-2018 Updated GradeCrossing, Mainboard, and SupportCircuits schematics to clarify J3 polarity relay connections.
12-15-2018 Added RPi mainboard component placement sheet to schematics.
11-25-2018 Code updated to See DnB_RpiCode for details.
11-24-2018 Updated all RPI circuit schematics to revision B. Sensors now use 2N5778 IR darlington transistors instead of the VS1838B. Schematic sheets reorganized to better group related circuits.
11-10-2018 Code updated to which supports 2nd 1x4 keypad. Changes to CLI options; see DnB_RpiCode for details.
11-08-2018 Updated the D&B RPi Schematics page; servo signal measurements, block detector details, and links to supporting PDF documents.
11-07-2018 Updated RPi schematics. 2nd 1x4 keypad added for manual Holdover track selection. Keypad indicators rewired.
11-03-2018 Code updated to Updated D&B RPi Code page with additional program descriptions.
10-28-2018 Added new section and initial pages for Raspberry Pi version of the control program. These pages are work-inprogress and are subject to frequent changes.
2-20-2012 Added MP4 version of all video clips to permit viewing on additional browsers and phone devices.
12-30-2006 Updated hardware schematics. Reorganized and consolidated propeller I/O pin usage. Moved grade crossing LED's to I/O pins to facilitate direct pulse width modulation by propeller chip.
12-06-2006 Added schematics and descriptions for propeller based hardware.
11-29-2006 Added pages for Parallax Propeller based redesign of the control electronics. Added software flow charts for Propeller code.
11-11-2006 Converted web pages to non-frame fromat in preparation for next phase of project.
2-03-2006 Added two photos to Photos Page 5. Added ten photos to Photos Page 6.
12-15-2005 Updated semaphore code to move arm at a more prototypical rate.
12-11-2005 Added video clips to the "Ride The D&B" page.
12-07-2005 Added a new clip to the "Ride The D&B" page. Also added "Boil That Cabbage Down" by the Smothers Brothers; railroad pretzels and vicious puma's.
11-24-2005 Added a new page; "Ride The D&B". This page contains video clips that were created using a wireless video camera mounted on a flat car.
5-03-2005 Added the turntable version 2 updates. Version 2 includes changes to the hardware and electrical design. Software changes include code optimizations, the use of 8x micro-stepping, and adjustments to timing constants. Additional code description text was also added.
4-27-2005 Added video clips to the Turntable and Video Clips pages.
4-23-2005 Added link in index to video clips page.
4-18-2005 Added video clips to grade crossing page.
4-16-2005 Updated the grade crossing code and description pages with version 2 of the program code. Added a flow chart of the train detection logic.
3-06-2005 Added some progress pictures of the backdrop to Photos Page 5.
9-05-2004 Updated More Photos Pages. Rearranged and added pictures of El Capitan.
8-15-2004 New progress photos added to More Photos Page5.
6-19-2004 New progress photos added to More Photos Page4 and Page5. Added links to mirror server. Non 24 hour uptime for now but no advertising banners or bandwidth limitations.
6-16-2004 General html updates to improve performance and correction of broken links.
3-28-2004 Added More Photos page 4.
2-16-2004 Code correction and new functionality added to the Turntable code. Included a gear backlash movement into the initial home sensor find operation. This results in more consistent turntable bridge positioning from session to session.

The turntable bridge can now be randomly positioned if no commanded activity has been performed for a user specified time interval. To enable this feature, the RandomMove constant must be set to a non-zero value.

An initial automatic move to a turntable bridge position at power up can now specified. To enable this feature, the InitPos and InitEnd constants must be set to non-zero values.

2-07-2004 Minor updated to the mainline code. Added functionality to alternate usage of the Block1 and Block2 holdover tracks when neither are occupied.
12-20-2003 Updated turntable code and description. New command for re-indexing the turntabe to the home position sensor in operate mode. Added code to position the turntable to track one on power up following home sensor seek operation.
10-21-2003 Added turntable page and pictures.
10-20-2003 Updated turntable schematic. Changed RC1 and RC2 resistors from 56k to 39k to eliminate motor step "chirping".
10-09-2003 Added turntable hardware description page.
10-05-2003 Added turntable control schematic. Added October pictures to More Photos Page 3.
9-28-2003 Added turntable and associated tracks to track plan.
9-11-2003 Added pictures to the 'Grade Grossing' and 'More Photos Page 3' pages. Crossing gates now operational., code, and description pages updated to reflect operational code.
8-15-2003 Updated block signal code. Added code to maintain semaphore servo position during long periods of inactivity. Updated grade crossing page, broke up more photos page into multiple pages, and added pictures of grade crossing.
8-08-2003 Updated block signal code, block detector schematic, and block detector hardware description. Changed block detector circuit to a voltage doubler design to improve sensitivity. Optimized block signal code to reduce program size and improve performance.
8-04-2003 Updated block signal schematic. Added alternate circuit for balancing red/green Led intensity using two diodes and a variable resistor.
7-31-2003 Updated mainline code and schematic. Sensors were added to detect train position on hidden hold over tracks. Code was added to illuminate panel indicators based upon sensor input. Removed midway siding code that was added for automatic handling of an occupied siding. Automatic functions interfered with manually entered turnout positioning.
7-29-2003 Updated block signal code. Added code to the signal color setting logic to ensure proper color priority; red (highest), yellow, and green (lowest) are displayed. Updated mainline code. Added logic to set the midway siding turnouts properly if the primary siding route is occupied. Updated yard route code. Reduced storage size of turnout addresses from WORD to BYTE to reduce overall code size.
7-23-2003 Updated block signal code and associated schematic. Signal L8 is now a semaphore signal and uses a R/C servo to position the semaphore arm. Added pictures to 'Block Signal' page and 'More Photos' page.
7-15-2003 Updated block signal code and associated schematic to show the use of diodes for yellow signal color adjustment.
7-07-2003 Updated grade crossing code. Refined time values and added code to stop signal for stationary train.
6-20-2003 Updated block detector schematic. Added missing resistor and updated notes on page.
6-15-2003 Updated grade crossing code, hardware and software description pages, and schematic. Updated file with new code. Added pictures to More Photos page.
6-10-2003 Updated grade crossing code and description pages. Updated file with new code. Updated grade crossing schematic and hardware description.
6-06-2003 Added functionality to grade crossing code for R/C servo control of gates. Updated code and description pages. Updated file with new code.
6-05-2003 Added functionality to grade crossing code to produce a gradual on/off effect for signal lamp Led's. Updated code and description pages. Updated file with new code.
6-02-2003 Added block signal hardware description. Updated block signal page; added pictures and logic table.
5-29-2003 Updated block signal code and code description.
5-25-2003 Updated grade crossing related information. Added disclaimer to initial page.
5-18-2003 Added thumbnails to "MorePhotos" page. Added 7 photos.
5-15-2003 Initiated change history page. Added yard hardware description page and added link in schematic section of index.

Color Bar

Planning and Construction:   Design Goals   Track Plan   Photos   Scenery Base
Basic Stamp Control Electronics:   Main line   Yard   Grade Crossing   Block Signal   Turntable
Circuit Description:   Main line   Yard   Grade Crossing   Block Signal   Block Detector   Turntable   Power Supply   Schematics
Photos and Video clips:   Photo 1   Photo 2   Photo 3   Photo 4   Photo 5   Photo 6   Video Clips   Ride The D&B
Propeller Control Electronics:   Overview   Flow Charts   Program Code   Schematics   Photos
Navigation:  D&B Home Index

Copyright © 2006-2019 Don Buczynski
San Diego, California