1. Science and Engineering Festival Some Robotic STEM Ideas
Craig Shelden

2. Robot Connections with STEM
Combines disciplines
Engineering
Math
Technology
Scientific Method
Makes abstract ideas real.

3. Thoughts on Programming
Clear Problem Statement
Pseudocode
Draw out what’s being attempted
Words First.
Program – Test – Program – Test ---> Repeat
Value of default settings… ?
Make things easier to program…
Make students think through every block they program
Approaches vary with goals and Team choices

4. WeDo Programming

5. Sailor Max Basic boat movement Basic boat movement with sound effects
basic_boat.wedo
boat_sounds.wedo

6. WeDo – Complex Capability with Sailor Max
Motion and sound with tilt sensor
Motion and sound with tilt triggered by proximity sensor
storm.wedo

7. WeDo – NXT-G Connection
Similar:
Syntax
Coloring
Left – to – right program flow

8. NXT-G Simple Area Measurement
Given a circle… How to measure its area using a robot?
Circumference = 2πr
Area = π r2 r
Pause Here…

9. NXT-G Simple Area Measurement
Given a circle… How to measure its area using a robot?
Circumference = 2πr
Area = π r2
One approach might be to:
measure all the way around the circle
calculate the radius
calculate the area
Area = C2/(4 π) r

10. One Circle Measuring Solution

11. NXT-G Simple Area Measurement
Given a circle… How to measure its area using a robot? Other ways….
Circumference = 2πr
Area = π r2 r
Are there other ways?

12. NXT-G Simple Area Measurement
Given a circle… How to measure its area using a robot? Other ways….
Circumference = 2πr
Area = π r2
Cross on a diameter and determine measurement…. r

13. NXT-G Complex Robotic Behavior - Sumo

14. Consider This Program Architecture
Define Variables
Monitor Sensor # 1  Variable # 1
Monitor Sensor # 2  Variable # 2 …
Act
Act (Values)
Act
Record desired data
See one of the sumo programs

15. Subsumptive Programming Architecture
See one of the sumo programs
Source: Brooks: A Robust Layered Control System for a Mobile Robot

16. NXT-G – Data Collection and Analysis Area Measurement

17. NXT-G – Data Collection and Analysis Area Measurement
How to measure the perimeter and area of an arbitrary closed shape?
Pause Here…

18. NXT-G – Data Collection and Analysis Area Measurement
How to measure the perimeter and area of an arbitrary closed shape? Consider Descartes’ method:
INSTRUCTIONS
Beginning with any vertex, list the coordinates of the vertices in order, moving counter-clockwise around the polygon. List the first pair again at the end.
Find the diagonal products from left to right.
Find the diagonal products from right to left.
Sum each column of products.
Find their difference and divide by 2.
This is the polygon’s area.
Could we do this by driving a robot around the shape?
From Area the Easy Way

19. NXT-G – Data Collection and Analysis Area Measurement
X new = X old + ΔX
Y new = Y old + ΔY
Need to generate (x, y) pairs as the robot follows the line around… But unlike the plotted curve, the robot does not know what the next pair will be. Need to find a way to remember the last point and calculate the next one. Just a little trigonometry… and a compass.
(X old, Y old)
North
Distance
(X new, Y new)
Heading ΔX ΔY
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
Inspired by Area the Easy Way

20. NXT-G – Data Collection and Analysis Area Measurement
X new = X old + ΔX
Y new = Y old + ΔY
Need to generate (x, y) pairs as the robot follows the line around… But unlike the plotted curve, the robot does not know what the next pair will be. Need to find a way to remember the last point and calculate the next one. Just a little trigonometry… and a compass.
Distance
(X old, Y old)
North
Heading ΔX ΔY
(X new, Y new)
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
Sine and cosine provide positive and negative factors that scale the sides of the right triangle.
Inspired by Area the Easy Way

21. NXT-G – Data Collection and Analysis Area Measurement
Show development of the path as the robot follows along the orange curve.
X new = X old + ΔX
Y new = Y old + ΔY
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
Sine and cosine provide positive and negative factors that scale the sides of the right triangle.
Inspired by Area the Easy Way

22. NXT-G – Data Collection and Analysis Area Measurement
Show development of the path as the robot follows along the orange curve.
X new = X old + ΔX
Y new = Y old + ΔY
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg) ΔY ΔX
Sine and cosine provide positive and negative factors that scale the sides of the right triangle.
Inspired by Area the Easy Way

23. NXT-G – Data Collection and Analysis Area Measurement
Example path showing generated (x, y) pairs as the robot follows the line around.
X new = X old + ΔX
Y new = Y old + ΔY
North
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
(X2, Y2)
(X1, Y1) ΔY
(X0, Y0) ΔX
Sine and cosine provide positive and negative factors that scale the sides of the right triangle.
Inspired by Area the Easy Way

24. NXT-G – Data Collection and Analysis Area Measurement
Example path showing generated (x, y) pairs as the robot follows the line around.
X new = X old + ΔX
Y new = Y old + ΔY
North
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
(X2, Y2)
(X5, Y5)
(X1, Y1) ΔY
(X3, Y3)
(X4, Y4)
(X0, Y0) ΔX
Sine and cosine provide positive and negative factors that scale the sides of the right triangle.
Inspired by Area the Easy Way

25. NXT-G – Data Collection and Analysis Area Measurement – two plots
(X old, Y old)
North
Distance
(X new, Y new)
Heading ΔX ΔY
X new = X old + ΔX
Y new = Y old + ΔY
ΔX = Dist *Sine (Hdg)
ΔY = Dist *Cosine (Hdg)
Rectangle with Distance = 1 inch
Circle with Distance = 1 inch
Inspired by Area the Easy Way

26. NXT-G – Data Collection and Analysis Area Measurement – two plots
Rectangle with Distance = 1 inch
Circle with Distance = 1 inch
Red arrows indicate error accumulated through each run.
Inspired by Area the Easy Way

27. Mapping with More Sensors

28. Mapping with More Sensors

29. NXT-G – Data Collection and Analysis Pendulum Motion

30. Data Logging
See Pendulum Program pendulum.rbtx

31. Application
Measuring period of a pendulum common exercise for students
Period = 2π √(L/g)
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
12 ½ inches
84 ½ inches

32. Pendulum Data 84 ½ inches Ultrasonic sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity

33. Pendulum Data 84 ½ inches Ultrasonic sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity

34. Pendulum Data 84 ½ inches Light sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity

35. Pendulum Data 84 ½ inches Light sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
Light sensor

36. Pendulum Data 84 ½ inches Acceleration sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
The Acceleration sensor block measures the three axes of acceleration, x, y and z. It returns the readings as signed values ranging from -400 to +400 thus the scale factor is approximately 200 counts per g, so the sensor can measure +/- 2g. Using data wires, it can send out the x, y and z values and a logic signal (true/false) based on whether the x value is above or below a trigger value.

37. Pendulum Data 84 ½ inches Acceleration sensor
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
The Acceleration sensor block measures the three axes of acceleration, x, y and z. It returns the readings as signed values ranging from -400 to +400 thus the scale factor is approximately 200 counts per g, so the sensor can measure +/- 2g. Using data wires, it can send out the x, y and z values and a logic signal (true/false) based on whether the x value is above or below a trigger value.

38. Pendulum Relationships
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
The Acceleration sensor block measures the three axes of acceleration, x, y and z. It returns the readings as signed values ranging from -400 to +400 thus the scale factor is approximately 200 counts per g, so the sensor can measure +/- 2g. Using data wires, it can send out the x, y and z values and a logic signal (true/false) based on whether the x value is above or below a trigger value.

39. Pendulum Relationships
Maximum Light
Maximum Negative Acceleration
Minimum Ultrasonic Range
Exercise taken from Physics with Robotics by William Church, Tony Ford, and Natasha Perova.
Section 4.6 Swinging with Gravity
The Acceleration sensor block measures the three axes of acceleration, x, y and z. It returns the readings as signed values ranging from -400 to +400 thus the scale factor is approximately 200 counts per g, so the sensor can measure +/- 2g. Using data wires, it can send out the x, y and z values and a logic signal (true/false) based on whether the x value is above or below a trigger value.

40. Math Excursion See Pendulum Program pendulum.rbtx Lower the sample
Frequency to
Something near the
Pendulum period.
See Pendulum Program pendulum.rbtx

41. Simple Data Logging
See Pendulum Program pendulum.rbtx

42. Not So Automatic Data Logging
Limitations on data logging…
No way to automatically log variable values
Not all sensor vendors supply data logging capabilities
Log only four sensors
Use Variables
See Heading Log Program heading_log.rbtx
See Data Collecting MyBlocks
data_logging_myblocks.rbtx

43. Variables Much of the programming power comes from the ability to
read values
store values,
change values, and
act based on values.
Three types:
Number – How much?
Text – Say What?
Logical – True or False?

44. Consider This Program Architecture
Define Variables
Monitor Sensor # 1  Variable # 1
Monitor Sensor # 2  Variable # 2 …
Act
Act (Values)
Act
Record desired data

45. Two myBlocks for Data Logging
Technique to log data described in Terry Griffin’s book The Art of LEGO MINDSTORMS NXT-G Programming

46. Data File Header

47. Data Consolidation

48. Sample Data Logging Program
Bang_Bang_multilogger_display.rbtx
See: \data\line_data folder

49. Not So Automatic Data Logging
Technique to log data described in Terry Griffin’s book The Art of LEGO MINDSTORMS NXT-G Programming

50. Thoughts on Programming
Clear Problem Statement
Pseudocode
Draw out what’s being attempted
Words First.
Program – Test – Program – Test ---> Repeat
Value of default settings… ?
Make things easier to program…
Make students think through every block they program
Approaches vary with goals and Team choices

51. Robot Connections with STEM
Combines disciplines
Engineering
Math
Technology
Scientific Method
Makes abstract ideas real.

52. Some Robotic STEM Ideas
Science and Engineering Festival
Some Robotic STEM Ideas
Craig Shelden