Handy Board

1. Handy Board

2. Why the Handy Board • Designed to be the controller of small, mobil robots • Has many features that make it ideal for robotics projects • Integrated motor drivers • 32K bytes of memory • LCD screen • Integrated battery pack • Interactive C • Small size • Sensor connectors for digital and analog sensors

3. Handy Board Specifications • Motorola 6811 microprocessor with system clock at 2 MHz. • 32K of battery-backed CMOS static RAM. • Two L293D chips capable of driving four DC motors. • 16 x 2 character LCD screen. • Two user programmable buttons, one knob and one piezo beeper. • Powered header inputs for 7 analog sensors and 9 digital sensors.

4. Handy Board Specifications • Internal 9.6v nicad battery with built in recharging circuit. • Hardware 38 kHz oscillator and drive transistor for IR output and on-board 38 kHz IR receiver. • 8-pin powered connector to 6811 SPI circuit. • Expansion bus with chip selects. • 4.25 x 3.15 inches.

5. Handy Board

6. Expansion Board Specifications • 10 additional analog sensor inputs; • 4 inputs for active LEGO sensors (reflectance sensor and shaft encoder). • 9 digital outputs. • 6 servo motor control signals with power supply from the Handy Board's internal battery. • optional external power for servo motors.

7. Expansion Board Specifications • connector mount for Polaroid 6500 ultrasonic ranging system. • pass-through connector for the Handy Board's LCD screen.

8. Expansion Board

9. Charging • Adapter plugged directly into board. trickle-charge. (12-14 hours) • Adapter plugged into the Serial Interface/Battery Charger board with “NORMAL CHARGE” selected. Trickle-charge (12-14 hours) • Adapter plugged into the Serial Interface/Battery Charger board with “ZAP CHARGE” selected. Zap Charge mode (3 hours. DO NOT LEAVE IN THIS MODE)

10. Downloaders • Two primary components to Interactive C • 6811 downloader program • Interactive C application • Program named “pcode_hb.s19” must be present in the handy board to use Interactive C. • Bootstrap Mode • Turn off the board and then turn it on while holding down the stop button. When the two power LEDs go out it is in bootstrap mode.

11. Interactive C • A subset of C • Includes control structures, local and global variables, arrays, pointers, integers and floating point numbers • Data types • Int 16-bit integers • Long 32-bit integers • Float 32-bit floating point • Char 8-bit characters • No switch statements

12. Using IC • IC will perform any valid C statement • 2+2; • {beep(), sleep(2.0);beep()}; • Main function • If main function is present it will be run when the Handy Board is reset

13. Using IC • IC commands • load <filename> compiles and loads “filename” to the Handy Board • unload <filename> unloads “filename” and re-loads remaining files • list files, list functions, list globals lists files, functions or globals presently on the Handy Board • kill_all kills all currently running processes • Ps prints the status of currently running processes • Help displays a help screen of IC commands • Quit exits IC

14. Library functions • DC Motors • void fd(int m) turns on motor m in forward direction • void bk(int m) turns on motor m in backward direction • void off(int m) turns off motor m • void alloff() turns off all motors • void ao() turns off all motors • void motor(int m, int p) turns on motor m to power level p (p ranges from 100 to -100 or full forward to full backwards)

15. Library functions • Sensor input • int digital(int p) returns true false value of sensor in sensor port p • int analog(int p) returns value of sensor in sensor port p (value between 0 and 255) • User Buttons and knobs • int stop_button() returns value of STOP button (1=pressed,0=relesed) • int start_button() returns value of START button (1=pressed,0=relesed) • void stop_press() waits for STOP button to be pressed, then relesed and then issues a short beep and returns • void start_press() waits for START button to be pressed, then relesed and then issues a short beep and returns • int knob() returns the position of the knob as a value from 0 to 255

16. Library functions • Time Commands • void reset_system_time() sets system time to zero • long mseconds() returns system time in milliseconds • float seconds() returns system time in seconds • void sleep(float sec) sleeps for sec seconds • void msleep (long msec) sleeps for msec milliseconds

17. Library functions • Tone Functions • void beep() produces a 500 Hertz tone for .3 seconds • void tone(float frequency, float length) produces a tone at frequency Hertz for length seconds • void set_beeper_pitch(float frequency) sets the beeper tone to frequency Hertz • void beeper_on() turns on the beeper • void beeper_off() turns off the beeper

18. Library Functions • Process Functions • int start_process(function-call(…), [ticks], [stack-size]) returns an intiger process ID assigned to the new process • int kill_process(int pid) returns a 0 if the process was destroyed, 1 if the process cannot be found • void hog_processor() adds additional 256 ms to currently running process • void defer() process swaps out imediately after this function is called

19. Analog and Digital Sensor Inputs • Two banks sensor inputs • nine digital sensor inputs • seven analog sensor inputs

20. Sensor Circuitry • Each port is a 3-wire sensor (power, ground, signal) • 47K resistor provides half of a common voltage divider circuit • Default 5 volts when no signal is present

21. Sensor Inputs • Digital Inputs • True/False (Vsens>2.5/Vsens<2.5) • Analog Inputs • Range from 0 to 5 volts • Converted to 8-bit number • 0 to 255 decimal

22. Switch • Simple switch circuit -contact switch

23. Voltage Divider • Simple voltage divider circuit • Light sensors • Reflectance sensors

24. Reflectance Sensor • Emitter led • Current limiting resistor • Detector/photoresistor • Concept directly applies to Break beam sensors

25. Optical Distance Sensor GP2D12 • Modulated IR emitter • Projects a spot of modulated light onto target surface • Detector assembly • Light from the spot is focused by the detector lens • The focused light hits a special linear position-sensitive detector element

26. Optical Distance Sensor • The angle of incidence changes depending on the distance the light spot on target surface is from the Lens/Position Sensitive Detector

27. Hamamatsu UVTron • Sensor • Detects radiant energy int the 185-260nm range • Pulses when it absorbs radiation. • Driver Circuit • Monitors pulses from sensor and signals high when a set number of pulses have been detected.

28. Gears • Uses • To reverse the direction of rotation • To increase or decrease the speed of rotation • To move rotational motion to a different axis • To keep the rotation of two axis synchronized • Tradeoffs of increasing/decreasing speed • Gearing for high speed reduces torque • Gearing for high torque reduces speed

29. Gears • Gear Ratios • Representation of the size difference between the two gears 2:1 (two to one) • The smaller gear has to spin two times for the larger gear to spin a single time • Gear Trains • Combination of multiple gears • Produce larger gear ratios • Change axis of rotation • Synchronize gears

30. Lab • Ferguson room 18 • Equipment • Computers • Voltage Supplies • Voltage Meters • Oscilloscopes • Soldering equipment • Wave Generators • Manuals located in workbench drawers

31. BrainStem™ • 40 Mhz RISC processor • 5 channel, 10 bit A/D • 5 digital I/O lines • GP2D02 Driver • 1 MBit IIC port • IIC routing • status LED

32. BrainStem™ • 10, 1k TEA files • RS-232 serial port • reflex architecture • 4 concurrent TEA processes • 4 high resolution servo outputs • Onboard 1 Amp, 5V power regulation (low dropout)

33. TEA • Tiny Embedded Application • Exact subset of ANSI C • Runs on the TEA VM (virtual matine)

34. References • Robotic Explorations A Hands-On Introduction to Engineering by Fred G. Martin • http://handyboard.com/ • http://www.cse.unl.edu/~bradleyk/lego.htm

35. Questions