Overview | Main | State Machine | Events | IR | Tape | Drivetrain | PWM | Flash | Two Minute Timer | Bump
char getIRstate(char sensor): get the events-based state of a given IR sensor
char checkEvents(void): check for events to pass on to the state machine
The events module polls the low-level modules and converts changes in states of sensors or the robot itself into events that are useful to the state machine. Since it contains the definitions for the interesting ranges of duty cycle values for IR sensing, it also provides a public function to get the state, as opposed to the current value, of any IR sensor.
PSEUDOCODE
(Download Pseudocode .doc 39kb)
char getIRstate(char sensor)
Return the current state of the sensor that was passed in
char checkEvents(void)
Get the current state of the timer
If the timer is not expired and the previous state was not not expired
Set the timer’s state to not expired
Return “no event”
Else if the timer is expired and the previous state was not expired
Set the timer’s state to expired
Return “two-minute timer expired”
Get the current state of the front bump sensor
If the front bump sensor is on and the previous state was not on
Set the front bump sensor’s state to on
Return “front bump sensor now on”
Else if the front bump sensor is off and the previous state was not off
Set the front bump sensor’s state to off
Return “front bump sensor now off”
Get the current state of the back bump sensor
If the back bump sensor is on and the previous state was not on
Set the back bump sensor’s state to on
Return “back bump sensor now on”
Else if the back bump sensor is off and the previous state was not off
Set the back bump sensor’s state to off
Return “back bump sensor now off”
Get the current state of the center tape sensor
If the center tape sensor is black and the previous state was not black
Set the center tape sensor’s state to black
Return “center tape sensor now black”
Else if the center tape sensor is green and the previous state was not green
Set the center tape sensor’s state to green
Return “center tape sensor now green”
Else if the center tape sensor is white and the previous state was not white
Set the center tape sensor’s state to white
Return “center tape sensor now white”
Get the current state of the front left tape sensor
If the front left tape sensor is black and the previous state was not black
Set the front left tape sensor’s state to black
Return “front left tape sensor now black”
Else if the front left tape sensor is green and the previous state was not green
Set the front left tape sensor’s state to green
Return “front left tape sensor now green”
Else if the front left tape sensor is white and the previous state was not white
Set the front left tape sensor’s state to white
Return “front left tape sensor now white”
Get the current state of the front right tape sensor
If the front right tape sensor is black and the previous state was not black
Set the front right tape sensor’s state to black
Return “front right tape sensor now black”
Else if the front right tape sensor is green and the previous state was not green
Set the front right tape sensor’s state to green
Return “front right tape sensor now green”
Else if the front right tape sensor is white and the previous state was not white
Set the front right tape sensor’s state to white
Return “front right tape sensor now white”
Get the current state of the back left tape sensor
If the back left tape sensor is black and the previous state was not black
Set the back left tape sensor’s state to black
Return “back left tape sensor now black”
Else if the back left tape sensor is green and the previous state was not green
Set the back left tape sensor’s state to green
Return “back left tape sensor now green”
Else if the back left tape sensor is white and the previous state was not white
Set the back left tape sensor’s state to white
Return “back left tape sensor now white”
Get the current state of the back right tape sensor
If the back right tape sensor is black and the previous state was not black
Set the back right tape sensor’s state to black
Return “back right tape sensor now black”
Else if the back right tape sensor is green and the previous state was not green
Set the back right tape sensor’s state to green
Return “back right tape sensor now green”
Else if the back right tape sensor is white and the previous state was not white
Set the back right tape sensor’s state to white
Return “back right tape sensor now white”
Get the current duty cycle of the front 12-inch IR sensor
If the front 12-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the front 12-inch IR sensor’s state to zero duty cycle
Return “front 12-inch IR sensor now zero duty cycle”
Else if the front 12-inch IR sensor is within the thirty duty cycle band
If the previous state was not thirty duty cycle
Set the front 12-inch IR sensor’s state to thirty duty cycle
Return “front 12-inch IR sensor now thirty duty cycle”
Else if the front 12-inch IR sensor is within the seventy duty cycle band
If the previous state was not seventy duty cycle
Set the front 12-inch IR sensor’s state to seventy duty cycle
Return “front 12-inch IR sensor now seventy duty cycle”
Else
If the previous state was not other duty cycle
Set the front 12-inch IR sensor’s state to other duty cycle
Return “front 12-inch IR sensor now other duty cycle”
Get the current duty cycle of the back 12-inch IR sensor
If the back 12-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the back 12-inch IR sensor’s state to zero duty cycle
Return “back 12-inch IR sensor now zero duty cycle”
Else if the back 12-inch IR sensor is within the thirty duty cycle band
If the previous state was not thirty duty cycle
Set the back 12-inch IR sensor’s state to thirty duty cycle
Return “back 12-inch IR sensor now thirty duty cycle”
Else if the back 12-inch IR sensor is within the seventy duty cycle band
If the previous state was not seventy duty cycle
Set the back 12-inch IR sensor’s state to seventy duty cycle
Return “back 12-inch IR sensor now seventy duty cycle”
Else
If the previous state was not other duty cycle
Set the back 12-inch IR sensor’s state to other duty cycle
Return “back 12-inch IR sensor now other duty cycle”
Get the current duty cycle of the front left 9-inch IR sensor
If the front left 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the front left 9-inch IR sensor’s state to zero duty cycle
Return “front left 9-inch IR sensor now zero duty cycle”
Else if the front left 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the front left 9-inch IR sensor’s state to fifty duty cycle
Return “front left 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the front left 9-inch IR sensor’s state to other duty cycle
Return “front left 9-inch IR sensor now other duty cycle”
Get the current duty cycle of the front right 9-inch IR sensor
If the front right 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the front right 9-inch IR sensor’s state to zero duty cycle
Return “front right 9-inch IR sensor now zero duty cycle”
Else if the front right 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the front right 9-inch IR sensor’s state to fifty duty cycle
Return “front right 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the front right 9-inch IR sensor’s state to other duty cycle
Return “front right 9-inch IR sensor now other duty cycle”
Get the current duty cycle of the front center 9-inch IR sensor
If the front center 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the front center 9-inch IR sensor’s state to zero duty cycle
Return “front center 9-inch IR sensor now zero duty cycle”
Else if the front center 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the front center 9-inch IR sensor’s state to fifty duty cycle
Return “front center 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the front center 9-inch IR sensor’s state to other duty cycle
Return “front center 9-inch IR sensor now other duty cycle”
Get the current duty cycle of the back left 9-inch IR sensor
If the back left 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the back left 9-inch IR sensor’s state to zero duty cycle
Return “back left 9-inch IR sensor now zero duty cycle”
Else if the back left 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the back left 9-inch IR sensor’s state to fifty duty cycle
Return “back left 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the back left 9-inch IR sensor’s state to other duty cycle
Return “back left 9-inch IR sensor now other duty cycle”
Get the current duty cycle of the back right 9-inch IR sensor
If the back right 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the back right 9-inch IR sensor’s state to zero duty cycle
Return “back right 9-inch IR sensor now zero duty cycle”
Else if the back right 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the back right 9-inch IR sensor’s state to fifty duty cycle
Return “back right 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the back right 9-inch IR sensor’s state to other duty cycle
Return “back right 9-inch IR sensor now other duty cycle”
Get the current duty cycle of the back center 9-inch IR sensor
If the back center 9-inch IR sensor is under the zero duty cycle high threshold
If the previous state was not zero duty cycle
Set the back center 9-inch IR sensor’s state to zero duty cycle
Return “back center 9-inch IR sensor now zero duty cycle”
Else if the back center 9-inch IR sensor is within the fifty duty cycle band
If the previous state was not fifty duty cycle
Set the back center 9-inch IR sensor’s state to fifty duty cycle
Return “back center 9-inch IR sensor now fifty duty cycle”
Else
If the previous state was not other duty cycle
Set the back center 9-inch IR sensor’s state to other duty cycle
Return “back center 9-inch IR sensor now other duty cycle”
Get the current state of the flash sensor
If the flash sensor is on and the previous state was not on
Set the flash sensor’s state to on
Return “flash sensor now on”
Else if the flash sensor is off and the previous state was not off
Set the flash sensor’s state to off
Return “flash sensor now off”
Return “no event”