1	2007 NMRA Jamboree
2	Unique Electronic Devices You Can Make!
3	Introduction – About me: Retired from public education An active model railroader for less than four years Electronics, ham radio, woodworking, computers & programming have been hobbies for decades Model railroading is a nice way to utilize those other interests in one hobby Primarily interested in using my electronics skills to enhance what can be done with a model railroad & teaching others to do the same!
4	Objectives Provide an overview of “hobbyist” microcontrollers Show how microcontrollers are programmed and connected to interact with railroad equipment Demonstrate various devices & projects that utilize microcontroller operation (Hopefully) Excite you with the possibilities and enable you to begin experimenting!
5	Hypothesis 1 We all have an interest in how things work and many of us have enough knowledge of basic electronics to know that something can be done… we just need a bit of help putting all of the parts together to make it happen!
6	Hypothesis 2 We Know About: Batteries & power supplies Track wiring & motors DC & polarity Voltage & amperage & resistance LEDs (what an improvement we have seen in the last 5 years!!) Series / parallel circuits Switches – SPST (on/off), SPDT, DPDT, transistors Programming
7	Hypothesis 3 Inexpensive microcontrollers allow us to optimize the basic electronics and programming knowledge that we have so that we can do some amazing (and personally satisfying) things!
8	“Hobbyist” Microcontrollers They have been around for about 15 years Usually dedicated to a single purpose Small Inexpensive (lately!) Programmed in BASIC Programming requires nothing more than a computer with a serial or USB port
9	Highly Recommended: PICAXE Designed in the UK for use in schools SUPERB support Free manuals, tutorials and software Active & helpful forums on their web page & elsewhere on the web Book: “Programming & Customizing the PICAXE Microcontroller” PICAXE manuals, especially “section 3- Interfacing Circuits” are super in helping to put it all together on your railroad
10	PICAXE Best choice in terms of: Capability Ease of use Cost Support dave@davebodnar.com info@trainelectronics.com
11	First Project: Flashing Crossing Lights Design objectives: Alternately flash two red LEDs Operate from battery power Alter timing and other characteristics from software
12	First Project: Flashing Crossing Lights Then we will modify the circuit to: Start from a button push Do other “flashing” things by making minor changes in hardware & software
13	Flashing Crossing Lights Parts: Cost: < $10.00
14	Flashing Crossing Lights Other items needed: Software from www.PICAXE.com Any Windows PC with serial port (or USB to serial adapter) programming cable Needs only 3 wires - can use an old mouse cable Soldering iron & wire cutters, etc. A Solderless Development Package is available from www.phanderson.com for < $20.00 2 to 5.5 volt power supply (3 @ AA cells)
15	Flashing Crossing Lights
16	Flashing Crossing Lights
17	Flashing Crossing Lights
18	Flashing Crossing Lights Program 1: Note: the program remains in the chip’s memory until it is manually erased or overwritten.
19	Flashing Crossing Lights Program 2: Note: “start” is just a label telling the “goto” where to go.
20	Flashing Crossing Lights Program 3: modified to flash 10 seconds and turn off for 10 seconds
21	Flashing Crossing Lights Hardware modification for button or reed switch activation:
22	Flashing Crossing Lights Program 4: modified to flash 5 seconds on each button push
23	Flashing Crossing Lights on Steroids! Program 5:
24	Lighthouse or Airport Beacon Design objectives Gradually brighten a bulb or LED to near full brightness Momentarily flash to full brightness Gradually dim till off Delay for a set time Repeat Able to use LEDs or incandescent bulbs
25	Lighthouse Beacon
26	Lighthouse Beacon Parts Adds one resistor and one transistor to the flasher circuit so that the PICAXE can control a high current bulb The most significant changes are to the software
27	Lighthouse Beacon – 4 LEDs
28	Lighthouse Beacon – Halogen Bulb
29	Lighthouse Beacon Pulsed Width Modulation
30	Lighthouse Beacon Program #6
31	Lighthouse Beacon Transistor makes it possible to drive a very bright bulb Substitute a motor for the bulb and you can control a train’s DC motor! Size of motor only limited by the size of the transistor
32	We Can Now Control Lights Motors Turnouts Relays Most electrically power devices
33	Actions Start Based on Time Switches of all kinds Toggle switch Push button switch Reed switch & magnet Any type of sensor
34	Detecting Events My favorite way to detect trains is with a pulsed infrared detector Pulses of IR are sent out at a rate of 38,000 pulses per second (38 KHz) The detector only responds to IR at that frequency
35	Pulsed IR Detector Creating 38 KHz pulses with the PICAXE is simple pwmout irled, 25, 52
36	Pulsed IR Detector A single 3 pin chip detects the 38 KHz pulses
37	Pulsed IR Detector
38	Pulsed IR Detector
39	Pulsed IR Detector
40	Pulsed IR Detector
41	Pulsed IR Detector
42	Infrared Object Detection PICAXE sends out pulses, detects them and controls the motor in response to what is “sees” Prototype:
43	Infrared Object Detection Program
44	Infrared Object Detection
45	Turnout Control The mechanism that is used in an electrically operated switch is either a motor or a solenoid This allows us to use the same type of circuitry to control switches as we use with motors.
46	Turnout Control
47	Turnout Control via IR Remote
48	PIC Microcontrollers Advantages: More program memory (10+ single spaced pages of code!) More capable programming languages Faster executing programs Higher chip clock speeds Can directly drive an LCD display
49	PIC Microcontrollers Disadvantages: Require a separate programmer Software NOT free Can be more difficult to work with Less support More research / experimentation required But… Expanded capabilities make it worth the effort!
50	Multi-Scale Train Speedometer Grew out of a discussion about another article for Garden Railways Experimented with “repurposing other things” as a train speedometer (i.e. bicycle speedometer, counter, etc)
51	Multi-Scale Train Speedometer Final design: 4 line x 20 character backlit LCD display Supports scales from 1:1 to 1:220 Common scales identified by name Track-side sensors Counts laps Gives speed in real & scale MPH Option to “beep” out speed English or Metric units
52	Multi-Scale Train Speedometer Wireless option: Uses radio transmitter on a modified car Senses train speed and sends it to the display unit Also can report voltage and current on a battery operated engine
53	Multi-Scale Train Speedometer Voltage and Current can also be included in the packet that is transmitted
54	Auto-Reverse Controller Originally designed to operate the motor on my holiday incline Repurposed the Speedometer by adding a power transistor, relay and additional control buttons
55	Auto-Reverse Controller Grew into a more capable unit: Time between reversing up to 8 minutes Random time option LED readout of time till reverse Timed deceleration point Variable top and bottom speed settings Remembers settings if powered down
56	Auto-Reverse Controller BARC 2 Potentiometers to adjust time / speed 2 Buttons to set options Mosfet to handle high (10 amp+) current motors 3 LEDs to show time & laps completed 176, 172, 167, 163, 158, 154
57	Custom Designs Dual tower lift bridge geared stepper motors TV remote control programming
58	Custom Designs Crossover collision avoidance control Main line & trolley point-to-point cross Sensors operate trolley and stop or start it based on the position of the train
59	Custom Designs Infrared Train ID system Each train carries a small IR transmitter that continuously sends its ID number Trackside receiver “reads” ID and triggers devices based on train that passes
60	Custom Designs Crossing signal activation / control Pulsed Infrared sensors Microcontroller start / stop / timing
61	Your Ideas? Questions?
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