1	2006 National Garden Railway Convention
2	Electronic Gadgets in the Garden
3	Introduction – About me: Retired from public education (science / math teacher then technology training & administration) Garden railroader for less than four years Electronics, ham radio, woodworking, computers & programming have been life-long hobbies Primarily interested in using my electronics skills to enhance what can be done with a garden railway & teaching others to do the same!
4	Objectives Provide an introduction to microcontroller interaction with electronic devices 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 of a 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 in your garden
10	PICAXE Best choice in terms of: Capability Ease of use Cost Support dave@davebodnar.com
11	First Project: Flashing Crossing Lights Design objectives: Alternately flash two red LEDs Starts flashing when powered on or when a button is pushed Battery power Alter timing and other characteristics from software
12	Flashing Crossing Lights Parts: Cost: < $10.00
13	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
14	Flashing Crossing Lights
15	Flashing Crossing Lights
16	Flashing Crossing Lights
17	Flashing Crossing Lights Program 1: Note: the program remains in the chip’s memory until it is manually erased or overwritten.
18	Flashing Crossing Lights Program 2: Note: “start” is just a label telling the “goto” where to go.
19	Flashing Crossing Lights Program 3: modified to flash 10 seconds and turn off for 10 seconds
20	Flashing Crossing Lights Hardware modification for button or reed switch activation:
21	Flashing Crossing Lights Program 4: modified to flash 5 seconds on each button push
22	Flashing Crossing Lights on Steroids! Program 5:
23	Lighthouse 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 accommodate LEDs or halogen lights
24	Lighthouse Beacon
25	Lighthouse Beacon Parts Adds one resistor and one transistor to the flasher circuit The most significant changes are to the software
26	Lighthouse Beacon
27	Lighthouse Beacon – 1 LED
28	Lighthouse Beacon – 4 LEDs
29	Lighthouse Beacon – Halogen Bulb
30	Lighthouse Beacon Pulsed Width Modulation
31	Lighthouse Beacon Program #6
32	Lighthouse Beacon Transistor makes it possible to drive a very bright bulb Substitute a motor for the bulb and you control a train’s DC motor!
33	Motor Control with PWM My first major project with the PICAXE Robot Train Battery operated, PICAXE controlled train Forward / reverse / gradual acceleration / deceleration Stop & reverse when it found magnets on the track Random pause between reversals
34	Digression #1
35	Repurposing Things Gadget to measure track length Grew out of a desire to know how much track I had in my main loop Needed an inexpensive counter that would count wheel rotations during one lap around the layout Remembered using a calculator to do that in a science classroom
36	Repurposing Things Try this on a calculator: 1 + 1 = = = = Reed switch under truck & magnet on wheel connected to “=“ key on calculator Wheel diameter X number of rotations = length of track December 2005 Garden Railways Magazine
37	Digression #2
38	Repurposing Things Laps completed counter Wanted to count laps completed by my “Robot Train” Could have used calculator but they “auto-off” after 7 or 8 minutes Noticed a $4.00 pedometer at Wal-Mart with a 5 digit LCD display
39	Repurposing Things Pedometer for laps completed Extended the wires from the “bounce” switch to a reed switch Each time the train passed, a magnet on the engine stimulated the reed switch and the count incremented Does not automatically shut off or reset like most calculators
40	Digressions Continue…
41	Children’s Hospital Layout Adding a “Momentum Effect”
42	So What's the Problem?
43	Ideas come from strange places
44	The Capacitor Did It!
45	Hazards / Precautions
46	One Capacitor Experiment
47	Problem – it only works in one direction
48	A Non-Polarized Capacitor
49	Children’s Hospital Installation
50	Where Else is this Useful?
51	Where Can You Put the Capacitors?
52	Trailing Car with Capacitors
53	Trailing Car with Capacitors
54	End Digressions…
55	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
56	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!
57	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)
58	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
59	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
60	Multi-Scale Train Speedometer Voltage and Current can also be included in the packet that is transmitted
61	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
62	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
63	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
64	Your Ideas? Questions?
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66	Auto-Reverse Controller BARC
67	Infrared Object Detection Eggliner prototype with commercial detection unit
68	Infrared Object Detection Areas for enhancement 9+ volts needed to operate sensor Relay gave full on or full stop Size makes concealment difficult Rapid oscillation between on / off Option to put beacon on car in front
69	Infrared Object Detection Using PICAXE to build on and enhance Ralph’s idea IR LED flasher (38 kHz) IR sensor – high when it sees 38 KHz Relay / resistor for speed control Timed delay to avoid choppy movement Addition of a beacon on forward train to extend distance (FRED)
70	Infrared Object Detection IR LED flasher (38 kHz)
71	Infrared Object Detection IR sensor – high when it sees 38 kHz
72	Infrared Object Detection Relay / resistor for speed control
73	Infrared Object Detection PICAXE sends out pulses, detects them and controls the motor in response to what is “sees” Prototype:
74	Infrared Object Detection Program
75	Infrared Object Detection
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77	Carnegie Science Center Lights
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79	Ditch lights example Idea from the ECLSTS 2 alternately flashing LEDs Not just on/off One brightens as the other dims
80	Two Wired Back-to-Back Most microcontrollers support only one PWM channel Wiring two LEDs “back-to-back” allows one channel to control one “up” & the other “down” in brightness
81	Potentiometer to Vary Brightness
82	PWM from PICAXE PWM output pin on PICAXE takes the place of the potentiometer
83	Ditch Light Software
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85	Mars Lights Idea from the LSOL forum request 7 LEDs light in a specific order to simulate a Mars light’s pattern One goes dim as the next brightens Utilizes higher speed PIC that can generate its own PWM pulses