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authorDat Nguyen <nguy2854@umn.edu>2019-10-02 10:36:22 -0500
committerDat Nguyen <nguy2854@umn.edu>2019-10-02 10:36:22 -0500
commit46b3520d9c20d0f7f56a9d83641a0a28b1354cf6 (patch)
tree6c0e7de360738a45a176b36470e5617962a82671 /System
parentDelete Motor.py (diff)
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Encoder class
Diffstat (limited to '')
-rw-r--r--System_Python/encoder.py74
-rw-r--r--System_Python/test_Encoder.py64
2 files changed, 84 insertions, 54 deletions
diff --git a/System_Python/encoder.py b/System_Python/encoder.py
new file mode 100644
index 0000000..b70fac6
--- /dev/null
+++ b/System_Python/encoder.py
@@ -0,0 +1,74 @@
+# Import required modules
+import RPi.GPIO as GPIO
+import time
+import math
+
+# Constants: parameters that the caller cannot modify
+# Delay: Minimum delay necessary after pull pin low to read input
+delay = 0.0000005
+
+# Encoder Class
+# This controls the motor at the given IO
+class Encoder:
+ def __init__(self, clk_pin, cs_pin, data_pin):
+ # Set the board IO (just in case it hasn't been done yet)
+ GPIO.setmode(GPIO.BCM)
+ # Setup class varaiable
+ self.offset=0
+ self.clk_pin = clk_pin
+ self.cs_pin = cs_pin
+ self.data_pin = data_pin
+ # Setup the IO
+ try:
+ GPIO.setup(self.clk_pin,GPIO.OUT)
+ GPIO.setup(self.cs_pin,GPIO.OUT)
+ GPIO.setup(self.data_pin,GPIO.IN)
+ # Setup the CS and CLK to be high
+ GPIO.output(PIN_CLK,1)
+ GPIO.output(PIN_CS,1)
+ except:
+ print("ERROR. Unable to setup the configuration required")
+ # Wait some time to before reading
+ time.sleep(0.5)
+ def setZero(self):
+ # Take current position as zero
+ self.offset=self.readPosition('Raw')
+ def clockup(self):
+ GPIO.output(self.clk_pin,1)
+ def clockdown(self):
+ GPIO.output(self.clk_pin,0)
+ def readPosition(self, format):
+ # Most of this is based of timing diagram of encoder
+ # Pull CS low to start reading
+ GPIO.output(self.cs_pin,0)
+ # Delay necessary before reading is ready
+ time.sleep(delay*2)
+ data = 0
+ # Clockdown necessary before reading
+ self.clockdown()
+ # Go through 10 bits needed to read
+ for i in range(0,10):
+ # Clock up to start reading one bit
+ self.clockup()
+ # Shift data left and insert input
+ data<<=1
+ data|=GPIO.input(self.data_pin)
+ # Clock down after finish reading
+ self.clockdown()
+ # Pull CS high after finish reading
+ GPIO.output(self.cs_pin,1)
+ # Format with offset, Max is 1024
+ data=(data+offset)%1024
+ # Data is linearly mapped
+ if format=="Raw":
+ return data
+ elif format=="Degrees":
+ degrees=data/(1024/360)
+ return degrees
+ elif format=="Radian":
+ radians=data/(1024/(2*math.pi))
+ return radians
+ else:
+ print("ERROR. Invalid format (Raw, Degrees, Radians)")
+ return None
+
diff --git a/System_Python/test_Encoder.py b/System_Python/test_Encoder.py
index ab74c6e..08804fa 100644
--- a/System_Python/test_Encoder.py
+++ b/System_Python/test_Encoder.py
@@ -1,58 +1,14 @@
+from encoder import Encoder
import time
-import RPi.GPIO as GPIO
-GPIO.setmode(GPIO.BCM)
+# Decide which pins to hook up to on the Pi before running
+clk_pin = 2
+cs_pin = 4
+data_pin = 3
-PIN_CLK = 2
-PIN_DATA = 3
-PIN_CS = 4
-delay = 0.0000005
+e = Encoder(clk_pin, cs_pin, data_pin)
+e.setZero()
-# pin setup done here
-try:
- GPIO.setup(PIN_CLK,GPIO.OUT)
- GPIO.setup(PIN_DATA,GPIO.IN)
- GPIO.setup(PIN_CS,GPIO.OUT)
- GPIO.output(PIN_CS,1)
- GPIO.output(PIN_CLK,1)
-except:
- print("ERROR. Unable to setup the configuration requested")
-
-#wait some time to start
-time.sleep(0.5)
-
-print("GPIO configuration enabled")
-
-def clockup():
- GPIO.output(PIN_CLK,1)
-def clockdown():
- GPIO.output(PIN_CLK,0)
-
-def readpos():
- GPIO.output(PIN_CS,0) #pulls low to start
-
- time.sleep(delay*2)
- data = 0
- clockdown()
-
- time1=time.clock()
- for i in range(0,10): #bitcount):
- clockup() #375 ns between each
- data<<=1
- data|=GPIO.input(PIN_DATA)
- #while(time.clock()-time1<minReadValue);
- clockdown()
- print(time.clock()-time1)
- GPIO.output(PIN_CS,1) #pull high after finish
-
- return data
-
-try:
- while(1):
- print(readpos())
- time.sleep(0.001)
- #break
-
-finally:
- print("cleaning up GPIO")
- GPIO.cleanup() \ No newline at end of file
+while(1):
+ print(e.readPosition('Degrees'))
+ time.sleep(0.001) \ No newline at end of file