System for Engine Location Final Presentation for EE 452 Senior Capstone Project Bradley University ECE Department Adam Weintrop and Paul Wimmer Advisors: Dr. Irwin / Dr. Schertz

2 Outline Background Engine Location Development Conclusion

3 Background AApplications PPrevious Work IInitial Work DDigital Train Control Engine Location Development Conclusion

4 Engine Location Addition to web train controlled over internet Provide local, instantaneous information regarding where the engines are and if they are moving User can see train over internet, but not real time Avoid train collisions, decouple train cars

5 Future Applications At the end of 2-3 years – a fully functional web train At the end of ten years – a system for toxic manufacturing automation At the end of 50 years – a underground mining operation on Mars

6 Outline Background AApplications PPrevious Work IInitial Work DDigital Train Control Engine Location Development Conclusion

7 Previous Work Two previous years have worked on implementing web train Train has already been laid out Previous work ended in disarray  Over voltages destroyed amplifier  Hardware was disassembled with poor documentation

8 Outline Background AApplications PPrevious Work IInitial Work DDigital Train Control Engine Location Development Conclusion

9 Initial Work Majority of time in lab spent trying to operate trains Train operation manual difficult to implement Had train enthusiast help us late in the fall to understand and reprogram the train engines

10 Outline Background AApplications PPrevious Work IInitial Work DDigital Train Control Engine Location Development Conclusion

11 Digital Command Control DCC is way of relaying commands to engines Asynchronous serial communication which includes train identification, command, and error checking

12 Standards DCC Standard DCC is based on period length not voltage levels Allows trains to be self clocking

13 Command Station Menu structure of the command station CChoose which train to operate CChoose speed of the train CChoose direction of the train

14 H-Bridge Microcontroller will flip pin to send to H-bridge controlling the track H-bridge has its direction pin as the input, yielding a unipolar 12V differential output Input is 5V unipolar differential and makes the H- bridge a good choice Op Amps only produce a single output or some only produce bipolar output H-Bridge replaced the broken Lenz LV101 Power Station, a $125 train power supply

15 Outline Background Engine Location Development Conclusion

16 Outline Background Engine Location Development BBlock Diagram HHardware Development HHardware / Software Interfacing SSoftware Development Conclusion

17 Overall Block Diagram

18 Outline Background Engine Location Development BBlock Diagram HHardware Development HHardware / Software Interfacing SSoftware Development Conclusion

19 Train Sensing Optical sensing would be illogical  Numerous sensors  Train track modification  Could be helpful for decoupling Electrical sensing is practical  Sensing can be done away from train layout  Cheaper than optical sensing

20 Train Sensing Methods Cannot determine # of trains if trains are at same location and instantaneous speed “2-bit” method can be designed cheap enough to have the A/D on every track segment, this eliminates analog multiplexers and analog noise “2-bit” Method Expensive and still requires analog multiplexer Can determine # of trains and # of cars 10-bit A/D Requires more software and analog multiplexer Built in the microprocessor board, # of trains 8-bit A/D with variable range ConsProsMethod

21 The “2-bit” Method Three train states are significant in this project Train is off that section Train is stopped at the section Train is running on that section

22 Hardware Schematic Transformer

23 Current Sensors Current changes with train presence and can be detected away from physical track Resistor was used first  Did not isolate the train supply circuit from rest of system  Large values barred sufficient train current, small values did not produce adequate sensing voltage Transformer  Isolates the detection and train circuits  Voltage is independent of energy drawn from train circuit

24 Hardware Schematic High Gain Amplifier

25 Hardware Schematic Rectifier and Filter D1 is half wave rectifier R3,C1,R4 form filter

26 Rectifier and Filter Diode rectifies voltage Filter cutoff frequency  Wanted DC, filter response became too slow Affects entering and exiting trains – “Ghost Train”  Too high of cutoff induces intermittent “Ghost Sightings”  340 Hz was found after experimentation to be a good balance between speed and bandwidth

27 Hardware Schematic Comparators Vrun is about 2.75V Vidle is about 260 mV

28 Hardware Schematic Limiting Rlim limits current into diodes and inverters Diodes limit voltage and HCMOS inverters provide buffering to rest of digital circuit Opto-islolators would provide more protection, but was overkill for this circuit

29 Outputs of Hardware (Active Low) RUN OFF IDLE

30 Outline Background Engine Location Development BBlock Diagram HHardware Development HHardware / Software Interfacing SSoftware Development Conclusion

31 Multiplexing to 4 multiplexer All outputs are OR’d together to combine to have 4 total outputs at one time Select lines are the same for all chips With different chip enable pins on each multiplexer Can sense 2 track sections at a time This can free up several I/O lines to the microprocessor

32 Outline Background Engine Location Development BBlock Diagram HHardware Development HHardware / Software Interfacing SSoftware Development Conclusion

33 Software Implementation Used C code on because  Software contains multiple loops to address multiplexers  Software execution time was not an issue for our system  Desire to learn embedded C

34 Software Plan Want to take information of train status and location and process Hardware outputs are numerous, need to be sorted Output where train is and status First step to more advanced software

35 Track Section 1 Track Section 2 Software Design Current of Section 1 >> Current of Section 2 “11”  Run“00”  Off Current of Section 1 = Current of Section 2 “11”  Run“11”  Run Current of Section 1 << Current of Section 2 “01”  Idle“11”  Run “Ghost Train” Train

36 Situations Ghost Train  Due to time constant of hardware, voltage does not fall rapidly  Idle train is detected where previously running  “Boo!” Software removes ghost trains

37 Software Development Where’s Waldo?

38 Flow Chart

39 Serial Communication Microcontroller will send via serial port train information Receive software on PC written in MATLAB and displays colors on track layout image MATLAB was chosen for its easy to use serial and graphic libraries

40 Serial Receive IDLE TRAIN RUNNING TRAIN

41 Outline Background Engine Location Development Conclusion

42 Outline Background Engine Location Development Conclusion FFuture Considerations CCurrent State

43 Future Considerations Derailed and shorted train allows high current to flow  Software will detect train everywhere rapidly  Serial port buffer fills causing delays in display Display could have direction, speed, distance added

44 Outline Background Engine Location Development Conclusion FFuture Considerations CCurrent State

45 Conclusion Locates up to 2 engines and displays on PC Low-cost system Easily installed and adaptable to other train systems System is readily expandable to support future projects Questions?

46 Questions? – We have answers A/D method?  Need precise A/D  Analog multiplexing  But a train with a heavy load could look like a faster train

47 More Answers Nonlinear amplifier?  More complex than necessary  Can be substituted for high gain amplifier in current system

48 More Answers Speed and Load Detection  Difficult without more accurate sampling method  A fast train could be confused with a heavily loaded train

49 More Answers Precision location for Decoupling  Optical Sensors  Could place decoupling magnet at edge of track section and stop when transition is detected