Sensing the World Intro to Robots

What are our senses and what organs do we use to enable these senses? Human Senses: What are our senses and what organs do we use to enable these senses? All work basically the same – receptors transmit signals to the brain for further processing. fingers hairs on skin skin ears inner ear tongue nose eyes Intro to Robots

Robots need senses and so we give them sensors Robot Senses Robots need senses and so we give them sensors sensitive to light, temperature, touch, distance to another object, etc typically electromechanical Proximity sensor: Infrared, sonar, laser differ in sensitivity and cost Scribbler has two IR emitters and one detector. Exercise: Find out how IR Proximity Detection works Intro to Robots

Scribbler Sensors Plus two more IR sensors underneath Intro to Robots

Scribbler Sensors: Light: three, located on the front of the robot, detect the levels of brightness (or darkness). Proximity: two tiny lamps ("headlights“), IR emmitters, light from these, if reflected by an obstacle bounces back and captured by the IR sensor Line: Underneath the Scribbler are two pairs of tiny holes. IR emitters and detectors, detect lines on the floor. Stall: internal sensor detects if robot is stalled or stuck when it is trying to move; ie, motor is turning over but wheels aren’t moving Intro to Robots

Getting to know your sensors: Start up your environment and execute joyStick(1). changes to 1 if the robot stalls changes to 0 if no object in front of robot 1 if it “sees” a thick line under the robot; 0 otherwise brighter the light; lower the number Most sensitive sensors Intro to Robots

How Sensitive is Scribbler? A lot more light sensitive – range(0,999) – than object sensitive (0/1) or line sensitive (0/1). This means we can expect it to be hard for Scribbler to do anything really sensitive. Intro to Robots

Exteroceptors and Interoceptors: Note that Scribbler can sense light using its light sensors. These are exteroceptors – external sensors. Scribbler can also understand it has stalled. This sense - that its wheels are not moving but its motors are – is the result of internal sensing or interoceptors. Intro to Robots

Proprioception with Scribbler Stall: Just because you give a command for the robot to move doesn’t mean it will actually happen. Time: We have already used wait() and timeRemaining and so many other functions have a TIME parameter. All computers have clocks 2.0 MHz CPU tells you how fast the CPU is and this depends how how fast its internal clock ticks. In computers, time is speed. Battery Level: Scribbler can also sense that its battery is low and it is time to recharge. forward(1, 2.5) Intro to Robots

Find out what a computer “clock” is. Check out Google and Wikipedia. Exercise: Find out what a computer “clock” is. Check out Google and Wikipedia. Intro to Robots

What is a Computer Program? A program is made up of two things – program code (instructions) and program data. This is also true of programs running on the robot. Is this how your own brain works? Does it have “code” and “data”? Which is which? What “data” does your robot work with? Is the chair that the robot bumped into also part of the robot’s program? obstacle = getIR(‘left’) if obstacle == 0: print ‘obstacle found’ else: print ‘no obstacle’ Intro to Robots