This document describes a series of thought experiments using simulated vehicles with increasing complexity to explore principles of intelligence and behavior. The vehicles are modeled after brain cells and neurons, using light sensors to simulate sensory input that differentially drives wheels based on excitatory and inhibitory connections, allowing behaviors like phototaxis, obstacle avoidance, and oscillation. Experiments are suggested to observe and analyze the behavior of each increasingly sophisticated vehicle.
4. Vehicles
1984 - Valentino Braitenberg,
cyberneticist, neuroanatomist and musician
publishes a series of thought
experiments.!
These explore the principles
of intelligence by building a
series of successively more
complicated creatures.!
5. Vehicle 1: Getting Around
• This
vehicle has
one sensor and one
motor.!
• Light
activates the
sensor and makes
the motor go
faster.
Vehicle 1
6. “A motile E.coli propels itself from
place to place by rotating its
flagella. To move forward, the
flagella rotate counterclockwise and
the organism ‘swims’. But when
flagellar rotation abruptly changes to
clockwise, the bacterium "tumbles" in
place and seems incapable of going
anywhere. Then the bacterium begins
swimming again in some new, random
direction.”!
“Swimming is more frequent as the
bacterium approaches a chemoattractant
(food). Tumbling, hence direction
change, is more frequent as the
bacterium moves away from the
chemoattractant. It is a complex
combination of swimming and tumbling
that keeps them in areas of higher
food concentrations.”!
http://www.cellsalive.com/animabug.htm
9. Getting Started
1. Start the Arduino IDE!
2. Input and save the program!
3. Select: Tools > Board > Arduino Uno!
4. Verify the program!
5. Connect the robot with the USB cable!
6. Select: Tools > Serial Port > COM*
or /dev/tty.usbmodem***!
7. Upload the program!
8. Disconnect the robot!
9. Switch the robot on!
10.Press a button to start the robot
10. V1 Experiments
1.Press any button to start/stop the
robot!
2.What happens if you cover its eyes?!
3.Shine a torch into its eyes.
Does it speed up or slow down?
11. Vehicle 2a: Fight or Flight
• This
vehicle has two
sensors and two
motors.!
• Light
drives the
motors differentially.!
• The
+ is an excitatory
connection.!
Vehicle 2a
• It
flees from
the light.
12.
13. V2a Experiments
1.Leave the robot connected and start
the Serial Monitor. !
2.Shine a torch into its eyes.
What’s the largest output value?!
3.Cover its eyes.
What’s the smallest output value?!
4.Can you steer it with the torch?
14. Vehicle 2b: Fight or Flight
• It
has positive
phototaxis, directed
movement towards a
light.!
• It
rushes towards the
light.
Vehicle 2b
15. V2b Experiments
1.Can you steer it with the torch?!
2.Which is easier to steer?!
3.Which is more fun?
16. Vehicle 3a: Love
• Light
inhibits the
motors, causing it to
come to rest and bask
in the sunshine.!
• The
- is an inhibitory
connection.!
• This
Vehicle 3a
time, the
uncrossed connections
turn the vehicle to
face the light.
17.
18. V3a Experiments
1.Can you steer it with the torch?!
2.Place the robot under a table,
in the dark. How does it behave?!
3.Does it try to get out from under
the table?
19. Vehicle 3b: Love
• Vehicle
3b shies away
from the light that
calms it.
Vehicle 3b
20. V3b Experiments
1.Can you steer it with the torch?!
2.Place the robot under a table,
in the dark. How does it behave?
21. Vehicle 3c: Love
• In
vehicle 3c both
excitatory and inhibitory
connections are summed at
the motors.!
• If
the excitation exceeds
the inhibition the wheel
moves forwards.!
• If
Vehicle 3c
the inhibition
overcomes the excitation
it moves backwards.
23. Vehicle 4: Values and
Special Tastes
• Vehicle
4 adds another
sensor to detect the
range of an obstruction.!
• It
has a single brain
cell, or neuron, that
fires if an obstruction
is too close.!
• This
Vehicle 4
stops the robot and
puts it into reverse.
24.
25. V4 Experiments
1.Use the Serial Monitor to look at
the output from the range sensor.!
2.Modify the println() to look at the
thresholded value. At what range
does it change?!
3.How good is this robot at avoiding
obstacles?
26. Vehicle 5a: Logic
• Neurons
can perform
internal computations.!
• The
left neuron fires
only if the left input
exceeds the right. Vice
versa on the right side.!
• With
Vehicle 5a
two negative
inputs, the motors need
a positive bias.
27.
28. V5a Experiments
1.Use the Serial Monitor to look at
the l,r values.
Are they ever on at the same time?!
2.Is this robot easier or harder to
steer?
29. Vehicle 5b: Logic
• Neurons
can be
oscillators.!
• The
output cycles
between -1 and 1!
• This
signal can be
used to turn heads
Vehicle 5b
30. V5b Experiments
1.Use the Serial Monitor to look at
the oscillator output.!
2.Is this robot better at avoiding
obstacles?
31. Summary
• The
artificial
neurons we have
been developing
are inspired by
real neurons. !
• Excitatory
and
inhibitory inputs
are summed at the
dendrites.
• If
a critical
threshold is reached,
the neuron fires
along its axon.