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author | Dat Nguyen <nguy2854@umn.edu> | 2019-10-02 10:36:22 -0500 |
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committer | Dat Nguyen <nguy2854@umn.edu> | 2019-10-02 10:36:22 -0500 |
commit | 46b3520d9c20d0f7f56a9d83641a0a28b1354cf6 (patch) | |
tree | 6c0e7de360738a45a176b36470e5617962a82671 /System_Python/encoder.py | |
parent | Delete Motor.py (diff) | |
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Encoder class
Diffstat (limited to '')
-rw-r--r-- | System_Python/encoder.py | 74 |
1 files changed, 74 insertions, 0 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 + |