1	"Microprocessor Controlled Engines" Microprocessor Controlled Engines It is much easier than you may think
2	Objectives: Introduce the basics of programming and using microprocessors to control lights, motors and other devices Explore the use of simple microprocessor based controllers in garden railway applications Allow time for discussion and questions
3	Microprocessor Control BASIC Stamp www.parallax.com “PICAXE microcontrollers are exciting, low-cost, re-programmable chips that can be used as low-cost 'brains' in many kinds of electronic projects. “ www.picaxe.com
4	Microprocessor Control PICAXE 08M is an 8 pin integrated circuit that can be used to control lights, sound boards, motors and other devices It is also able to “sense” Touch Light Motion other things in its environment
5	Microprocessor Control The key to its simplicity is the capability to program it in BASIC rather than a more complex and difficult to learn language All software and documentation are free Extensive support and sample programs are available Chips range in price from less than $4.00 to around $20.00 Even the simplest chip is VERY capable!
6	Flashing Crossing Lights First Project: Flashing crossing lights Objectives: Flash two red LEDs alternately Pause and repeat Battery power Alter timing from software
7	Flashing Crossing Lights 7404 based LED flasher circuit
8	Flashing Crossing Lights Parts:
9	Flashing Crossing Lights Other items needed: Any PC with serial port (or USB to serial adapter) programming cable needs only 3 wires can use old mouse cable Soldering iron & wire cutters Software from www.picaxe.com
10	Flashing Crossing Lights Circuit Diagram:
11	Flashing Crossing Lights
12	Flashing Crossing Lights
13	Flashing Crossing Lights Software:
14	Flashing Crossing Lights Software – modified to flash 10 seconds and turn off for 10 seconds
15	Flashing Crossing Lights Hardware modification for button or reed switch activation:
16	Flashing Crossing Lights Software – modified to flash 5 seconds on button push
17	Flashing Crossing Lights on Steroids!
18	Lighthouse Beacon Design objectives Gradually brighten a bulb or LED to near full brightness Flash to full brightness briefly Gradually dim till off Delay for a set time Repeat Provide for LED or halogen lights
19	Lighthouse Beacon
20	Lighthouse Beacon Parts Adds one resistor and one transistor to the flasher circuit The most significant changes are to the software
21	Lighthouse Beacon LED circuit diagram:
22	Lighthouse Beacon Pulsed Width Modulation
23	Lighthouse Beacon
24	Lighthouse Beacon Halogen bulb circuit diagram adds a voltage regulator and larger transistor
25	Infrared Object Detection Eggliner prototype with commercial detection unit
26	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
27	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)
28	Infrared Object Detection IR LED flasher (38 kHz)
29	Infrared Object Detection IR sensor – high when it sees 38 kHz
30	Infrared Object Detection Relay / resistor for speed control
31	Infrared Object Detection Picaxe sends out pulses, detects them and controls the motor in response to what is “sees” Prototype:
32	Infrared Object Detection Software
33	Infrared Object Detection
34	Crossing Gate with Lights & Sound Objectives: Detect passing train with 38 KHz pulsed IR sensor Lower crossing gate with servo Flash crossing lights Sound crossing bell Continue till 10 seconds passes without detection
35	Crossing Gate with Sound Hardware: Picaxe for control 38 KHz IR transmitter and detector Inexpensive bell module Amplifier and speaker Radio control airplane servo LED lights for crossing Battery or solar power
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37	"' 0=38 kHz pulse chip..." ' 0=38 kHz pulse chip – ' 1=LED – ' 2=LED – ' 3=input from IR receiver – ' 4=Servo control symbol flashdelay = 15 init: high 0: low 1: low 2 servo 4, 100 start: b3=0 low 0 '38kHz on pause 3 if pin3=0 then train: high 0 pause 100 goto start: train: high 0 high 1: low 2 for b1=100 to 190 step 1 pause 15 b2=b2+1 if b2< flashdelay then skip1: toggle 1: toggle 2 b2=0 skip1: servo 4, b1 next b1 loop1: b3=b3+1 pause 250 toggle 1: toggle 2 low 0 pause 3 if pin3 = 0 then loop1: high 0 pause 250 low 0 pause 3 if pin3 = 0 then loop1: if b3<9 then loop1: ' only stop if no IR for 9 loops high 0 for b1=190 to 100 step -1 pause 15 b2=b2+1 if b2< flashdelay then skip2: toggle 1: toggle 2 b2=0 skip2: servo 4, b1 next b1 goto init:
38	Robot Train Objectives: Complete speed and direction control Start gradually and accelerate smoothly to top speed Detect magnet on track (reed switch) Decelerate Pause Reverse Repeat
39	Hardware – H-Bridge Motor control is accomplished with an LM293D H-Bridge chip The LM293D can provide up to 1 amp of current Three pins on the LM293 will be connected to the PICAXE. Two are used for direction control and the third, called enable, for speed.
40	Robot Train
41	Other projects: User programmable Morse beacon PWM / remote control track power control speedometer block detection / control Your ideas? ? ?
42	Questions ? ? ?
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