EGR 450 - MANUFACTURING CONTROLS
               DRAG RACE TIMING SYSTEM
 
 

SYSTEM DESCRIPTION:

This system is a Drag Race timing system centered around a micro-controller. The system consists of the Christmas Tree (the three yellows, the green and red lights), the fault sensor (checks to see if a racer started racing before the green light), the finish line which stops the running timer, and the display (which shows the time). The micro-controller is used to track the racers time final time, calculate the avg. speed for the 1/4 mile and then display it. The timing circuit is accurate to the hundredths of a second, and the speed display shows the avg. speed over the 1/4 mile track based upon the 1/4 mile time in whole miles/hour.
 

    Photos of System:   Track       Electronics


SYSTEM PURPOSE:

To show that complicated systems can be controlled by inexpensive micro-controllers. This project was completed to prove the feasibility of a full blown drag race timing system being controlled by a simple micro-controller. If a processor with more memory was used for a full scale project a second lane could have easily been added. This particular micro-controller and board costs less than $100. The sensors run about $200 per complete set. The AB sensor's I used for this project do not necessarily need to be used. An equally accurate, and less expensive option would be advisable if this system were ever to go to production. These are readily available, but a different type of sensor would most likely be used on a full scale unit. This demonstration display shows that a complicated system can be managed very accurately for less than $500.


SYSTEM INFORMATION:
 

This project was built using an HC11 EVBU (Evaluation Board) with a Motorola M68HC11E9 52-Pin PLCC/CLCC Processor with the standard 512 bytes of EEPROM.  In addition to the HC11, two Allen Bradley sensing units were acquired. These specific units are not necessary for this project as other sensing options could be accommodated easily, however the AB units were chosen because they are robust and reliable.
 
Components:
  1. 1 - HC11 EVBU with M68HC11E9 52-Pin PLCC/CLCC Processor
  2. 2 - AB Sensor Units P/N = 42GRF-9002 - Infrared sensing unit with internal relay
  3. 4 - AB Fiber Optic Leads for AB Sensors  P/N = 99-504-1 C
  4. 1 - Frame or Table to build system on
  5. 1 - Contact Switch with Common, NC and NO leads
  6. 2 - Circuit Breadboards
  7. 3 - Yellow LEDs
  8. 1 - Green LED
  9. 1 - Red LED
  10. Wire Leads
  11. Wire
  12. 4 - Cathode 7 - Segment Displays
  13. 1 - BCD Display Driver   P/N = 74LS47 Generic
  14. 1 - Hex Inverter P/N =74LS04
  15. 4 - TIP 31C
  16. 2 - Terminal Strips
  17. 1 - Modem Serial Cable
  18. The program MCP.asm
  19. An Assembler (Freely Available from Motorola)
  20. A Terminal Emulator
        THE INPUTS TO THE SYSTEM ARE ALL LOCATED ON PORT-E OF THE HC11 EVBU.
PORT E IS ADDRESSED AT $100A

PORT E / 0    PIN 43    INDEXED AT = $01    ; LOGIC HIGH ON THIS PIN BYPASSES THE BUFFALO MONITOR PROGRAM ON RESET.  THIS PIN IS TO BE DRIVEN LOGIC LOW DURING PROGRAMMING, AND SWITCHED TO LOGIC HIGH DURING OPERATION.

PORT E / 1    PIN 45    INDEXED AT = $02    ; LOGIC LOW ON THIS PIN INDICATES THE FAULT LINE HAS BEEN CROSSED.

PORT E / 2    PIN 47    INDEXED AT = $04    ; LOGIC LOW ON THIS PIN INDICATED THE FINISH LINE HAS BEEN CROSSED.

PORT E / 3    PIN 49    INDEXED AT = $08    ; LOGIC HIGH INDICATED THE START BUTTON HAS BEEN PUSHED.
 

SENSING SYSTEM:

The sensors used in this system are Allen Bradley components. The sensing system is comprised of two AB infrared relay units. Attached to each of these units are two fiber optic leads. The emitting side of the sensor emits a infrared pulse down one of the two fiber optic leads. The second lead is connected to the receiver side of the AB unit. When the system is powered and the receiver is receiving the pulsed beam, the relay inside the AB switches. In our applications when the beam is detected a 5VDC or Logic High signal is sent to the HC11. When the beam is broken, the signal switches to 0VDC or Logic Low. The Switching time for the relay is 5 ms which is more than adequate for our needs.

Photos of the AB Units, Leads and Mounting:

Photos of the Switch:      AB Bottom     AB Front    AB Top  Leads Close -Up   Beam Path
 

        THE INPUTS TO THE SYSTEM ARE  LOCATED ON PORTS B AND C OF THE HC11 EVBU.
PORT B IS ADDRESSED AT $1004.  PORT B DRIVES THE 7-SEGMENT LED DISPLAY.

PORT B / 0    PIN 42    INDEXED AT = $01    ;    BCD 1 // LOGIC LOW = ON
PORT B / 1    PIN 41    INDEXED AT = $02    ;    BCD 2 // LOGIC LOW = ON
PORT B / 2    PIN 40    INDEXED AT = $04    ;    BCD 4 // LOGIC LOW = ON
PORT B / 3    PIN 39    INDEXED AT = $08    ;    BCD 8 // LOGIC LOW = ON
PORT B / 4    PIN 38    INDEXED AT = $10    ;    CH 1 (LED 1) // LOGIC HIGH = ON
PORT B / 5    PIN 37    INDEXED AT = $20    ;    CH 2 (LED 2) // LOGIC HIGH = ON
PORT B / 6    PIN 36    INDEXED AT = $40    ;    CH 3 (LED 3) // LOGIC HIGH = ON
PORT B / 7    PIN 35    INDEXED AT = $80    ;    CH 4 (LED 4) // LOGIC HIGH = ON
 

Basic circuit schematic: 7- SEGMENT LED SCHEMATIC

Photos of  7- Segment LED:     FRONT  BACK BOTH DISPLAYS
 

PORT C IS ADDRESSED AT $1003.  PORT B DRIVES THE "CHRISTMAS TREE" OF LED LIGHTS.

PORT C / 0    PIN 09    INDEXED AT = $01    ;    NOT USED
PORT C / 1    PIN 10    INDEXED AT = $02    ;    NOT USED
PORT C / 2    PIN 11    INDEXED AT = $04    ;    NOT USED
PORT C / 3    PIN 12    INDEXED AT = $08    ;    YELLOW 3 (TOP YELLOW)
PORT C / 4    PIN 13    INDEXED AT = $10    ;    YELLOW 2 (MIDDLE YELLOW)
PORT C / 5    PIN 14    INDEXED AT = $20    ;    YELLOW 1 ( LOWEST YELLOW)
PORT C / 6    PIN 15    INDEXED AT = $40    ;    GREEN
PORT C / 7    PIN 16    INDEXED AT = $80    ;    RED

Additional Note:  In order to utilize Port C as outputs, the Register DDRC at $1007 needs to be set to the value of $FF. The normal reset mode for Port C is all inputs. Until $FF is written to DDRC at $1007, the lights will be lit dimly. This is because a CMOS device's (like the HC11) inputs nominally float to 2.5VDC when not being driven. Until the DDRC configures Port C and $00 is written to Port C at $1003 the lights will be in an indeterminate state.
 

Basic circuit schematic: LED LIGHT SCHEMATIC

Photos of LED Christmas Tree:   Christmas Tree Front   Back BOTH DISPLAYS
 
 

ADDITIONAL PINS

In addition to the pins mentioned above, there are several pins that are used that do not fall into the above category. The reason mentioning these pins here is that they are not switched via the HC11, these are the Ground and VDC +5V. Digital Logic High on Pin 26 gives a constant +5VDC supply to the HC11. This can be used to drive logic, but can NOT be used to drive any of the displays. The voltage drop of more than a few milliVolts will put the HC11 into a reset state.

Vdd = VDC +5V       PIN 26    ; Special note, the logic high is interrupted by a reset, thus this pin can NOT be used to bypass the BUFFALO routine via PortE/0.

GND                         PIN 01    ; Note that this pin is connected directly to ground. Simple LED's can be grounded here, however the 7-Segment display should be connected to the EVBU's source's ground.

Photos of Ideal Power Source // Ground Location:  Ideal wiring uses the EVBU's power port.
 
 

SYSTEM CONSTRUCTION NOTES:
Basic circuit schematic: LED LIGHT SCHEMATIC

Photos of LED Christmas Tree:   Christmas Tree Front   Back BOTH DISPLAYS

Basic circuit schematic: 7- SEGMENT LED SCHEMATIC

Photos of  7- Segment LED:    FRONTBACK BOTH DISPLAYS

HC11 I/ MAP :  HC11IO.html

Hex Inverter Wiring Diagram: Hex Inverter

BCD converter and 7 Segment LED component diagrams: BCD and LED components

Wiring of AB Sensors:  Note: The wiring diagram is on the back of the sensor. The common of the relay is used to drive the input of the HC11.  5VDC is applied to NO, and DCGND is applied to the NC wires. This will supply 5VDC to the HC11 when the beam is sensed. Standard 110VAC is used to power the sensor units.

Each of the completed display units are to be plugged into the EVBU on the noted pin numbers.

All switches and relays must either provide a connection to 5VDC (Logic HIGH) or GND (Logic LOW).  No used input pins can be unconnected from a logic source. If this is not done the input will not be predictable.

Remember, the inverter chip on the display requires logic LOW to drive the display, whereas the TIP31's need logic HIGH to turn the display ON.

5VDC on pin 43 // Port E 0 - Will bypass BUFFALO and run the program in EEPROM directly.
 

PROGRAM CODE:
Assembly Program:    MCP.asm
 The Master Control Program for the Drag Race Timing System - Use a text program like notepad to view.


Partial Code:     Directory Listing of Partial Codes

 This directory contains useful subroutines I created.


Memory Map:    Memory_Locations.txt

The master list of memory addresses used in my program.
Compiled Binary:    MCP.s19
Native format for the HC11. This file can be directly downloaded into the HC11 EEPROM and run.
Program List:       MCP.lst
The MCP with line numbers included for easy reference. Contains extra information not found in MCP.asm, but can not be compiled in this format.