Add specific exit codes for each extreme

Signed-off-by: Matt Strapp <matt@mattstrapp.net>

1 files changed, 373 insertions, 373 deletions

diff --git a/System/pendulum/system.py b/System/pendulum/system.py
index 4a49492..07c04bf 100644
--- a/System/pendulum/system.py
+++ b/System/pendulum/system.py
@@ -1,373 +1,373 @@
-#!/usr/bin/env python

-from .motor import Motor

-from .encoder import Encoder

-import math

-from datetime import datetime

-from time import sleep

-import RPi.GPIO as GPIO

-import sys

-# import os

-count2 = 0

-##

-import cmath

-##

-

-

-

-

-from threading import Thread, Lock

-

-# IO pin definitions

-### Motor pins

-motor_torque_pin = 17

-motor_forward_pin = 27

-motor_reverse_pin = 22

-### Encoder pins (shared by both encoders)

-encoder_clock_pin = 3

-encoder_data_pin = 2

-### Angular encoder pins

-encoder_angular_cs_pin = 4

-### Linear encoder pins

-encoder_linear_cs_pin = 23

-### Limit switch pins (configured to PULLUP)

-

-#FLIPPING THESE BELOW

-#limit_negative_pin = 19

-#limit_positive_pin = 26

-limit_negative_pin = 26

-limit_positive_pin = 19

-

-# System parameters

-system_max_x = 16.5

-system_min_x = -16.5

-downloads_reference_dest = "."

-default_results_fileName = "results"

-

-

-# System Class

-# This is the primary interface a student will use to control the pendulum.

-class System:

-    def __init__(self, negative_limit=float('nan'), positive_limit=float('nan'), angular_units='Degrees', sw_limit_routine=None):

-        GPIO.setwarnings(False)

-        self.deinit = False

-        # Initialize public variables

-        self.max_x = system_max_x

-        self.min_x = system_min_x

-        # Initialize the motor.

-        self.motor = Motor(motor_torque_pin, motor_forward_pin, motor_reverse_pin)

-        # Initialize the angular encoder.

-        self.encoder_angular = Encoder(encoder_clock_pin, encoder_angular_cs_pin, encoder_data_pin)

-        self.encoder_angular.set_zero(offset = 512) # set offset so that 0 is upright vertical

-        # Initialize the linear encoder.

-        self.encoder_linear = Linear_Encoder(encoder_clock_pin, encoder_linear_cs_pin, encoder_data_pin)

-        # We assume that the system has been initialized on startup to a 0 position, or that the previous run ended by returning the system to 0

-        self.encoder_linear.set_zero()

-        

-        self.angular_units = angular_units

-        

-        # Enable hardware interrupts for hardware limit switches

-        GPIO.setup(limit_negative_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

-        GPIO.add_event_detect(limit_negative_pin, GPIO.FALLING, callback=self.negative_limit_callback)

-        GPIO.setup(limit_positive_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

-        GPIO.add_event_detect(limit_positive_pin, GPIO.FALLING, callback=self.positive_limit_callback)

-        self.interrupted = False

-        

-        # Setup soft limits if defined by the user (this is "challenge mode" for the user, making the constraints more difficult).

-        # By default, the soft limits will not be used (when set NaN), and the whole extent of the system is available (to the HW limits).

-        self.negative_soft_limit = negative_limit

-        self.positive_soft_limit = positive_limit

-        # If both limits have been defined, verify that they are valid (i.e. positive limit must be greater than the negative limit)

-        if not math.isnan(negative_limit) and not math.isnan(positive_limit) and not negative_limit < positive_limit:

-            print("ERROR: Invalid software limits provided. Must be valid floating-point numbers and positive limit must be greater than negative limit. Software limits will be disabled.")

-            self.negative_soft_limit = float('nan')

-            self.positive_soft_limit = float('nan')

-        # NOTE: If only one limit has been defined, this should always work (hardware limits will be the absolute edge on the undefined side, although this would be difficult for users to utilize unless we provide the position of the hardware limits on each side

-        # NOTE: If neither limit is defined, the hardware limits will be the only limits in effect.

-        self.sw_limit_routine = self.limit_triggered

-        if sw_limit_routine is not None:

-            self.sw_limit_routine = sw_limit_routine

-        

-        # Create and setup results file (to be sent back to the server and displayed/downloaded to the user)

-        # Results file is a CSV with the following entries: angle, position, torque

-        self.result_filename = f"{sys.argv[0].split('.')[0]}.csv"

-        print("self.result_filename")

-        print(self.result_filename)

-        # Open the file for write mode.  The file will get created, assuming it does not already exist.

-        result_file = open(self.result_filename, "x")

-        result_file.write(f"timestamp,angle({angular_units}),position(inches),torque(percentage)\n")

-        result_file.close()

-        

-        # Setup a thread to constantly be measuring encoder positions

-        #self.encoder_thread = EncoderThread(instance = self)

-        self.encoder_thread = Thread(target = self.encoder_thread_routine)

-        self.encoder_thread.setDaemon(True)

-        self.angular_position = 0.

-        self.linear_position = 0.

-        self.encoder_thread.start()

-    # END __init__()

-    

-    # Destructor

-    # Brake the motor and call GPIO.cleanup as a last-chance of doing so

-    def __del__(self):

-        self.motor.brake()

-        GPIO.cleanup()

-    # END __del__()

-    

-    def initialize(self):

-        print("begin initialize")

-        # Temporarily disable the limit switch interrupts: we do not want the program to exit if the switch is triggered

-        GPIO.remove_event_detect(limit_negative_pin)

-        GPIO.remove_event_detect(limit_positive_pin)

-        # Begin moving slowly in the negative direction until the negative limit switch is triggered

-        if not GPIO.input(limit_negative_pin) == False:

-            self.motor.move(-5)

-            pressed = True

-            while pressed != False:

-                pressed = GPIO.input(limit_negative_pin)

-                #print(pressed)

-                sleep(0.01)

-        self.motor.brake()

-        print("hit negative end stop")

-        # Set zero at the negative end of the track for easy reference in determining the extent

-        self.encoder_linear.set_zero()

-        sleep(1)

-        # Begin moving slowly in the positive direction until the positive limit switch is triggered

-        self.motor.move(5)

-        pressed = True

-        while pressed != False:

-            # We must continue reading linear encoder motion to keep track of rotations

-            pressed = GPIO.input(limit_positive_pin)

-            sleep(0.01)

-        self.motor.brake()

-        print("hit positive endstop")

-        # Get the current position (the extent of the track)

-        extent = self.linear_position

-        # Move back towards the center until we reach position extent/2

-        position = extent

-        sleep(1)

-        self.motor.move(-4)

-        while position >= (extent / 2.):

-            position = self.linear_position

-            #print(position)

-            sleep(0.015) 

-        self.motor.brake()

-        # Set zero again: this is the real zero

-        self.encoder_linear.set_zero()

-        # Re-enable the limit switch interrupts

-        GPIO.add_event_detect(limit_negative_pin, GPIO.FALLING, callback=self.negative_limit_callback, bouncetime=300)

-        GPIO.add_event_detect(limit_positive_pin, GPIO.FALLING, callback=self.positive_limit_callback, bouncetime=300)

-        print("Finished the initialize func")

-    # END initialize

-    

-    # Return home, cleanup IO. This should be called when exiting the program

-    def deinitialize(self):

-        self.return_home()

-        self.motor.brake()

-        self.deinit = True

-        if self.encoder_thread.is_alive():

-            self.encoder_thread.join()

-        sleep(1)

-        GPIO.cleanup()

-    

-    # Get the values of the encoders to determine the angular and linear position of the pendulum.

-    # Values are returned as a tuple: (angle, linear).

-    ### angle: 0 indicates the pendulum is exactly straight up.

-    #####      180 or -180 indicate the pendulum is exactly straight down.

-    #####      Positive values indicate the pendulum is leaning to the right.

-    #####      Negative values indicate the pendulum is leaning to the left.

-    ### linear: 0 indicates the pendulum is exactly in the middle of the track.

-    #####       Positive values indicate the pendulum is right-of-center.

-    #####       Negative values indicate the pendulum is left-of-center.

-    def measure(self):

-        return (self.angular_position, self.linear_position)

-    # END measure()

-    

-    

-    # Thread routine (0.1s interval). Get the values of the encoders to determine the angular and linear position of the pendulum.

-    # Values are saved in the class (self.angular_position and self.linear_position), which are then simply returned by measure()

-    def encoder_thread_routine(self):

-        limit_serviced = False

-        while self.deinit == False:

-            angular_position = self.encoder_angular.read_position(self.angular_units)

-            if self.angular_units == 'Degrees':

-                if angular_position > 180.:

-                    angular_position = angular_position - 360.

-            self.angular_position = angular_position

-            self.linear_position = self.encoder_linear.read_position()

-            # Check soft limits

-            if (not math.isnan(self.negative_soft_limit)) and self.linear_position < self.negative_soft_limit: #or self.linear_position < self.min_x:

-                if limit_serviced == False:

-                    limit_serviced = True

-                    # SW limit reached: stop the motor, set the interrupted flag so that the motor cannot continue to move until the interrupt has been completely serviced

-                    #self.interrupted = True

-                    self.motor.brake()

-                    # Print negative soft limit violation to the results file.

-                    result_file = open(self.result_filename, "a")

-                    result_file.write("Negative software limit %f has been reached!\n" % self.negative_soft_limit)

-                    result_file.close()

-                    # Fire the limit trigger method

-                    self.sw_limit_routine()

-            elif (not math.isnan(self.positive_soft_limit)) and self.linear_position > self.positive_soft_limit: #or self.linear_position > self.max_x:

-                if limit_serviced == False:

-                    limit_serviced = True

-                    # SW limit reached: stop the motor, set the interrupted flag so that the motor cannot continue to move until the interrupt has been completely serviced

-                    #self.interrupted = True

-                    self.motor.brake()

-                    # Print positive soft limit violation to the results file.

-                    result_file = open(self.result_filename, "a")

-                    result_file.write("Positive software limit %f has been reached!\n" % self.positive_soft_limit)

-                    result_file.close()

-                    # Fire the limit trigger method

-                    self.sw_limit_routine()

-            elif limit_serviced == True and self.linear_position > (self.negative_soft_limit+0.5) and self.linear_position < (self.positive_soft_limit-0.5):

-                # Clear the limit service flag once we return to a reasonable range that the limit will not trigger again

-                limit_serviced = False

-            # This thread should run on ~0.01s intervals

-            sleep(0.01)

-    

-    # Adjust the pendulum's linear position using the motor.

-    ### torque: Acceptable values range from -100 to 100 (as a percentage), with 100/-100 being the maximum adjustment torque.

-    #####      Negative values will move the pendulum to the left.

-    #####      Positive values will move the pendulum to the right.

-    def adjust(self, torque):

-        if self.interrupted == False:

-            if torque != 0:

-                # cap the torque inputs

-                if torque > 100.:

-                    torque = 100.

-                if torque < -100.:

-                    torque = -100.

-                # change the motor torque

-                # TODO: Make sure the motor is oriented so that positive torque the correct direction (same for negative). Change the values otherwise.

-                self.motor.coast()

-                self.motor.move(torque)

-            else:

-                self.motor.coast()

-    # END adjust()

-    

-    # Append data to the results file

-    def add_results(self, angle, position, torque):

-        # open the results file

-        result_file = open(self.result_filename, "a")

-        # Write the results

-        result_file.write("%s," % datetime.now().strftime("%H:%M:%S.%f"))   # Write current time

-        result_file.write("%f," % angle)                                    # Write angle

-        result_file.write("%f," % position)                                 # Write position

-        result_file.write("%f\n" % torque)                                   # Write torque (end of line)

-        # Close the results file

-        result_file.close()

-    # END add_results

-    

-    def add_log(self, message):

-        # open the results file

-        result_file = open(self.result_filename, "a")

-        # Write the log

-        result_file.write("%s\n" % message)

-        # re-write the csv headers for next logging

-        result_file.write(f"timestamp,angle({self.angular_units}),position(inches),torque(percentage)\n")

-        # Close the results file

-        result_file.close()

-    

-    # Go back to the zero position (linear) so that the next execution starts in the correct place.

-    def return_home(self):

-        position = self.linear_position

-        # slowly move towards 0 until we get there

-        if position > 0:

-            self.motor.move(-4)

-            while position > 0:

-                position = self.linear_position

-                sleep(0.015)

-            self.motor.brake()

-            return

-        else:

-            self.motor.move(4)

-            while position < 0:

-                position = self.linear_position

-                sleep(0.015)

-            self.motor.brake()

-            return

-    # END return_home

-    

-    # Callback for when negative limit switch is triggered.

-    def negative_limit_callback(self, channel):

-        self.interrupted = True

-        self.motor.brake()

-        # Print negative limit trigger to the results file.

-        result_file = open(self.result_filename, "a")

-        result_file.write("Negative hardware limit has been reached!\n")

-        result_file.close()

-        # Fire the limit trigger method (stops motor, kills program immediately).

-        self.limit_triggered()

-    # END negative_limit_callback

-    # Callback for when positive limit switch is triggered.

-    def positive_limit_callback(self, channel):

-        self.interrupted = True

-        self.motor.brake()

-        # Print positive limit trigger to the results file.

-        result_file = open(self.result_filename, "a")

-        result_file.write("Positive hardware limit has been reached!\n")

-        result_file.close()

-        # Fire the limit trigger method (stops motor, kills program immediately).

-        self.limit_triggered()

-    # END positive_limit_callback

-    def limit_triggered(self):

-        sleep(1)

-        self.deinitialize()

-        sys.exit(1)

-# END System

-

-# Linear Encoder class

-# This class is to help with using an absolute encoder for linear position sensing as assembled in the physical system.

-# The function definitions here are the same as with the regular encoder (pseudo-interface).

-class Linear_Encoder:

-    PROPORTION = 14.5

-    

-    def __init__(self, clk_pin, cs_pin, data_pin):

-        self.encoder = Encoder(clk_pin, cs_pin, data_pin)

-        self.set_zero()

-    def set_zero(self):

-        # Set the zero position for the encoder

-        self.encoder.set_zero()

-        # Reset the internal position counter

-        self.rotations = 0.

-        self.last_position = 0.

-        ###sam debug

-        self.last_position_filter = 0.

-        ###sam debug

-    def read_position(self):

-        ###sam debug

-        global count2

-        test = 0

-        count = 0

-        while test == 0:

-            count += 1

-            position = float(self.encoder.read_position('Raw') & 0b1111111100)

-            complex_current = cmath.exp(((position*2*math.pi)/1023)*1j)

-            complex_last = cmath.exp(((self.last_position*2*math.pi)/1023)*1j)

-            distance = math.sqrt((complex_current.real-complex_last.real)**2 + (complex_current.imag-complex_last.imag)**2)

-            if distance < 0.5 or count > 5: #this corresponds to a difference of 50 in the raw encoder position

-                test = 1

-            #print(count)

-            count2 = count2 + count - 1

-            print("global count")

-            print(count2)

-        ###sam debug

-

-        # Read the position of the encoder (apply a noise filter, we don't need that much precision here)

-        #position = float(self.encoder.read_position('Raw') & 0b1111111100)

-

-

-        # Compare to last known position

-        # NOTE: For now, assume that we are moving the smallest possible distance (i.e. 5 -> 1 is -4, not 1020)

-        if (position - self.last_position) > 768.:

-            self.rotations = self.rotations - 1.

-        elif (position - self.last_position) < -768.:

-            self.rotations = self.rotations + 1.

-        

-        # Save the last position for the next calculation

-        self.last_position = position 

-        # compute the position based on the system parameters

-        # linear position = (2pi*r)(n) + (2pi*r)(position/1024) = (2pi*r)(n + position/1024) = (pi*d)(n + position/1024)

-        print("sled position in inches")

-        print(self.PROPORTION*(self.rotations + position/1024.))

-        return((self.PROPORTION)*(self.rotations + position/1024.))

+#!/usr/bin/env python
+from .motor import Motor
+from .encoder import Encoder
+import math
+from datetime import datetime
+from time import sleep
+import RPi.GPIO as GPIO
+import sys
+# import os
+count2 = 0
+##
+import cmath
+##
+
+
+
+
+from threading import Thread, Lock
+
+# IO pin definitions
+### Motor pins
+motor_torque_pin = 17
+motor_forward_pin = 27
+motor_reverse_pin = 22
+### Encoder pins (shared by both encoders)
+encoder_clock_pin = 3
+encoder_data_pin = 2
+### Angular encoder pins
+encoder_angular_cs_pin = 4
+### Linear encoder pins
+encoder_linear_cs_pin = 23
+### Limit switch pins (configured to PULLUP)
+
+#FLIPPING THESE BELOW
+#limit_negative_pin = 19
+#limit_positive_pin = 26
+limit_negative_pin = 26
+limit_positive_pin = 19
+
+# System parameters
+system_max_x = 16.5
+system_min_x = -16.5
+downloads_reference_dest = "."
+default_results_fileName = "results"
+
+
+# System Class
+# This is the primary interface a student will use to control the pendulum.
+class System:
+    def __init__(self, negative_limit=float('nan'), positive_limit=float('nan'), angular_units='Degrees', sw_limit_routine=None):
+        GPIO.setwarnings(False)
+        self.deinit = False
+        # Initialize public variables
+        self.max_x = system_max_x
+        self.min_x = system_min_x
+        # Initialize the motor.
+        self.motor = Motor(motor_torque_pin, motor_forward_pin, motor_reverse_pin)
+        # Initialize the angular encoder.
+        self.encoder_angular = Encoder(encoder_clock_pin, encoder_angular_cs_pin, encoder_data_pin)
+        self.encoder_angular.set_zero(offset = 512) # set offset so that 0 is upright vertical
+        # Initialize the linear encoder.
+        self.encoder_linear = Linear_Encoder(encoder_clock_pin, encoder_linear_cs_pin, encoder_data_pin)
+        # We assume that the system has been initialized on startup to a 0 position, or that the previous run ended by returning the system to 0
+        self.encoder_linear.set_zero()
+        
+        self.angular_units = angular_units
+        
+        # Enable hardware interrupts for hardware limit switches
+        GPIO.setup(limit_negative_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
+        GPIO.add_event_detect(limit_negative_pin, GPIO.FALLING, callback=self.negative_limit_callback)
+        GPIO.setup(limit_positive_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
+        GPIO.add_event_detect(limit_positive_pin, GPIO.FALLING, callback=self.positive_limit_callback)
+        self.interrupted = False
+        
+        # Setup soft limits if defined by the user (this is "challenge mode" for the user, making the constraints more difficult).
+        # By default, the soft limits will not be used (when set NaN), and the whole extent of the system is available (to the HW limits).
+        self.negative_soft_limit = negative_limit
+        self.positive_soft_limit = positive_limit
+        # If both limits have been defined, verify that they are valid (i.e. positive limit must be greater than the negative limit)
+        if not math.isnan(negative_limit) and not math.isnan(positive_limit) and not negative_limit < positive_limit:
+            print("ERROR: Invalid software limits provided. Must be valid floating-point numbers and positive limit must be greater than negative limit. Software limits will be disabled.")
+            self.negative_soft_limit = float('nan')
+            self.positive_soft_limit = float('nan')
+        # NOTE: If only one limit has been defined, this should always work (hardware limits will be the absolute edge on the undefined side, although this would be difficult for users to utilize unless we provide the position of the hardware limits on each side
+        # NOTE: If neither limit is defined, the hardware limits will be the only limits in effect.
+        self.sw_limit_routine = self.limit_triggered
+        if sw_limit_routine is not None:
+            self.sw_limit_routine = sw_limit_routine
+        
+        # Create and setup results file (to be sent back to the server and displayed/downloaded to the user)
+        # Results file is a CSV with the following entries: angle, position, torque
+        self.result_filename = f"{sys.argv[0].split('.')[0]}.csv"
+        print("self.result_filename")
+        print(self.result_filename)
+        # Open the file for write mode.  The file will get created, assuming it does not already exist.
+        result_file = open(self.result_filename, "x")
+        result_file.write(f"timestamp,angle({angular_units}),position(inches),torque(percentage)\n")
+        result_file.close()
+        
+        # Setup a thread to constantly be measuring encoder positions
+        #self.encoder_thread = EncoderThread(instance = self)
+        self.encoder_thread = Thread(target = self.encoder_thread_routine)
+        self.encoder_thread.setDaemon(True)
+        self.angular_position = 0.
+        self.linear_position = 0.
+        self.encoder_thread.start()
+    # END __init__()
+    
+    # Destructor
+    # Brake the motor and call GPIO.cleanup as a last-chance of doing so
+    def __del__(self):
+        self.motor.brake()
+        GPIO.cleanup()
+    # END __del__()
+    
+    def initialize(self):
+        print("begin initialize")
+        # Temporarily disable the limit switch interrupts: we do not want the program to exit if the switch is triggered
+        GPIO.remove_event_detect(limit_negative_pin)
+        GPIO.remove_event_detect(limit_positive_pin)
+        # Begin moving slowly in the negative direction until the negative limit switch is triggered
+        if not GPIO.input(limit_negative_pin) == False:
+            self.motor.move(-5)
+            pressed = True
+            while pressed != False:
+                pressed = GPIO.input(limit_negative_pin)
+                #print(pressed)
+                sleep(0.01)
+        self.motor.brake()
+        print("hit negative end stop")
+        # Set zero at the negative end of the track for easy reference in determining the extent
+        self.encoder_linear.set_zero()
+        sleep(1)
+        # Begin moving slowly in the positive direction until the positive limit switch is triggered
+        self.motor.move(5)
+        pressed = True
+        while pressed != False:
+            # We must continue reading linear encoder motion to keep track of rotations
+            pressed = GPIO.input(limit_positive_pin)
+            sleep(0.01)
+        self.motor.brake()
+        print("hit positive endstop")
+        # Get the current position (the extent of the track)
+        extent = self.linear_position
+        # Move back towards the center until we reach position extent/2
+        position = extent
+        sleep(1)
+        self.motor.move(-4)
+        while position >= (extent / 2.):
+            position = self.linear_position
+            #print(position)
+            sleep(0.015) 
+        self.motor.brake()
+        # Set zero again: this is the real zero
+        self.encoder_linear.set_zero()
+        # Re-enable the limit switch interrupts
+        GPIO.add_event_detect(limit_negative_pin, GPIO.FALLING, callback=self.negative_limit_callback, bouncetime=300)
+        GPIO.add_event_detect(limit_positive_pin, GPIO.FALLING, callback=self.positive_limit_callback, bouncetime=300)
+        print("Finished the initialize func")
+    # END initialize
+    
+    # Return home, cleanup IO. This should be called when exiting the program
+    def deinitialize(self):
+        self.return_home()
+        self.motor.brake()
+        self.deinit = True
+        if self.encoder_thread.is_alive():
+            self.encoder_thread.join()
+        sleep(1)
+        GPIO.cleanup()
+    
+    # Get the values of the encoders to determine the angular and linear position of the pendulum.
+    # Values are returned as a tuple: (angle, linear).
+    ### angle: 0 indicates the pendulum is exactly straight up.
+    #####      180 or -180 indicate the pendulum is exactly straight down.
+    #####      Positive values indicate the pendulum is leaning to the right.
+    #####      Negative values indicate the pendulum is leaning to the left.
+    ### linear: 0 indicates the pendulum is exactly in the middle of the track.
+    #####       Positive values indicate the pendulum is right-of-center.
+    #####       Negative values indicate the pendulum is left-of-center.
+    def measure(self):
+        return (self.angular_position, self.linear_position)
+    # END measure()
+    
+    
+    # Thread routine (0.1s interval). Get the values of the encoders to determine the angular and linear position of the pendulum.
+    # Values are saved in the class (self.angular_position and self.linear_position), which are then simply returned by measure()
+    def encoder_thread_routine(self):
+        limit_serviced = False
+        while self.deinit == False:
+            angular_position = self.encoder_angular.read_position(self.angular_units)
+            if self.angular_units == 'Degrees':
+                if angular_position > 180.:
+                    angular_position = angular_position - 360.
+            self.angular_position = angular_position
+            self.linear_position = self.encoder_linear.read_position()
+            # Check soft limits
+            if (not math.isnan(self.negative_soft_limit)) and self.linear_position < self.negative_soft_limit: #or self.linear_position < self.min_x:
+                if limit_serviced == False:
+                    limit_serviced = True
+                    # SW limit reached: stop the motor, set the interrupted flag so that the motor cannot continue to move until the interrupt has been completely serviced
+                    #self.interrupted = True
+                    self.motor.brake()
+                    # Print negative soft limit violation to the results file.
+                    result_file = open(self.result_filename, "a")
+                    result_file.write("Negative software limit %f has been reached!\n" % self.negative_soft_limit)
+                    result_file.close()
+                    # Fire the limit trigger method
+                    self.sw_limit_routine()
+            elif (not math.isnan(self.positive_soft_limit)) and self.linear_position > self.positive_soft_limit: #or self.linear_position > self.max_x:
+                if limit_serviced == False:
+                    limit_serviced = True
+                    # SW limit reached: stop the motor, set the interrupted flag so that the motor cannot continue to move until the interrupt has been completely serviced
+                    #self.interrupted = True
+                    self.motor.brake()
+                    # Print positive soft limit violation to the results file.
+                    result_file = open(self.result_filename, "a")
+                    result_file.write("Positive software limit %f has been reached!\n" % self.positive_soft_limit)
+                    result_file.close()
+                    # Fire the limit trigger method
+                    self.sw_limit_routine()
+            elif limit_serviced == True and self.linear_position > (self.negative_soft_limit+0.5) and self.linear_position < (self.positive_soft_limit-0.5):
+                # Clear the limit service flag once we return to a reasonable range that the limit will not trigger again
+                limit_serviced = False
+            # This thread should run on ~0.01s intervals
+            sleep(0.01)
+    
+    # Adjust the pendulum's linear position using the motor.
+    ### torque: Acceptable values range from -100 to 100 (as a percentage), with 100/-100 being the maximum adjustment torque.
+    #####      Negative values will move the pendulum to the left.
+    #####      Positive values will move the pendulum to the right.
+    def adjust(self, torque):
+        if self.interrupted == False:
+            if torque != 0:
+                # cap the torque inputs
+                if torque > 100.:
+                    torque = 100.
+                if torque < -100.:
+                    torque = -100.
+                # change the motor torque
+                # TODO: Make sure the motor is oriented so that positive torque the correct direction (same for negative). Change the values otherwise.
+                self.motor.coast()
+                self.motor.move(torque)
+            else:
+                self.motor.coast()
+    # END adjust()
+    
+    # Append data to the results file
+    def add_results(self, angle, position, torque):
+        # open the results file
+        result_file = open(self.result_filename, "a")
+        # Write the results
+        result_file.write("%s," % datetime.now().strftime("%H:%M:%S.%f"))   # Write current time
+        result_file.write("%f," % angle)                                    # Write angle
+        result_file.write("%f," % position)                                 # Write position
+        result_file.write("%f\n" % torque)                                   # Write torque (end of line)
+        # Close the results file
+        result_file.close()
+    # END add_results
+    
+    def add_log(self, message):
+        # open the results file
+        result_file = open(self.result_filename, "a")
+        # Write the log
+        result_file.write("%s\n" % message)
+        # re-write the csv headers for next logging
+        result_file.write(f"timestamp,angle({self.angular_units}),position(inches),torque(percentage)\n")
+        # Close the results file
+        result_file.close()
+    
+    # Go back to the zero position (linear) so that the next execution starts in the correct place.
+    def return_home(self):
+        position = self.linear_position
+        # slowly move towards 0 until we get there
+        if position > 0:
+            self.motor.move(-4)
+            while position > 0:
+                position = self.linear_position
+                sleep(0.015)
+            self.motor.brake()
+            return
+        else:
+            self.motor.move(4)
+            while position < 0:
+                position = self.linear_position
+                sleep(0.015)
+            self.motor.brake()
+            return
+    # END return_home
+    
+    # Callback for when negative limit switch is triggered.
+    def negative_limit_callback(self, channel):
+        self.interrupted = True
+        self.motor.brake()
+        # Print negative limit trigger to the results file.
+        result_file = open(self.result_filename, "a")
+        result_file.write("Negative hardware limit has been reached!\n")
+        result_file.close()
+        # Fire the limit trigger method (stops motor, kills program immediately).
+        self.limit_triggered(3)
+    # END negative_limit_callback
+    # Callback for when positive limit switch is triggered.
+    def positive_limit_callback(self, channel):
+        self.interrupted = True
+        self.motor.brake()
+        # Print positive limit trigger to the results file.
+        result_file = open(self.result_filename, "a")
+        result_file.write("Positive hardware limit has been reached!\n")
+        result_file.close()
+        # Fire the limit trigger method (stops motor, kills program immediately).
+        self.limit_triggered(4)
+    # END positive_limit_callback
+    def limit_triggered(self, code):
+        sleep(1)
+        self.deinitialize()
+        sys.exit(code)
+# END System
+
+# Linear Encoder class
+# This class is to help with using an absolute encoder for linear position sensing as assembled in the physical system.
+# The function definitions here are the same as with the regular encoder (pseudo-interface).
+class Linear_Encoder:
+    PROPORTION = 14.5
+    
+    def __init__(self, clk_pin, cs_pin, data_pin):
+        self.encoder = Encoder(clk_pin, cs_pin, data_pin)
+        self.set_zero()
+    def set_zero(self):
+        # Set the zero position for the encoder
+        self.encoder.set_zero()
+        # Reset the internal position counter
+        self.rotations = 0.
+        self.last_position = 0.
+        ###sam debug
+        self.last_position_filter = 0.
+        ###sam debug
+    def read_position(self):
+        ###sam debug
+        global count2
+        test = 0
+        count = 0
+        while test == 0:
+            count += 1
+            position = float(self.encoder.read_position('Raw') & 0b1111111100)
+            complex_current = cmath.exp(((position*2*math.pi)/1023)*1j)
+            complex_last = cmath.exp(((self.last_position*2*math.pi)/1023)*1j)
+            distance = math.sqrt((complex_current.real-complex_last.real)**2 + (complex_current.imag-complex_last.imag)**2)
+            if distance < 0.5 or count > 5: #this corresponds to a difference of 50 in the raw encoder position
+                test = 1
+            #print(count)
+            count2 = count2 + count - 1
+            print("global count")
+            print(count2)
+        ###sam debug
+
+        # Read the position of the encoder (apply a noise filter, we don't need that much precision here)
+        #position = float(self.encoder.read_position('Raw') & 0b1111111100)
+
+
+        # Compare to last known position
+        # NOTE: For now, assume that we are moving the smallest possible distance (i.e. 5 -> 1 is -4, not 1020)
+        if (position - self.last_position) > 768.:
+            self.rotations = self.rotations - 1.
+        elif (position - self.last_position) < -768.:
+            self.rotations = self.rotations + 1.
+        
+        # Save the last position for the next calculation
+        self.last_position = position 
+        # compute the position based on the system parameters
+        # linear position = (2pi*r)(n) + (2pi*r)(position/1024) = (2pi*r)(n + position/1024) = (pi*d)(n + position/1024)
+        print("sled position in inches")
+        print(self.PROPORTION*(self.rotations + position/1024.))
+        return((self.PROPORTION)*(self.rotations + position/1024.))