Hi,
I have a Kubler D-78054 rotary encoder connected to the version 1 Bpod Rotary Encoder module.
The pins are connected as outlined in the documentation for the international brain lab (brown to 5V, green to A, grey to B, blue to Z and white to GND).
I am using the following code (mostly from the pybpod_rotaryencoder_module) to stream the position via usb.
from pybpodapi.com.arcom import ArCOM, ArduinoTypes
class RotaryEncoderModule(object):
COM_HANDSHAKE = "C"
COM_TOGGLEEVTTRANSM = ord("V")
COM_TOGGLEOUTPUTSTREAM = ord("O")
COM_TOGGLESTREAM = ord("S")
COM_STARTLOGGING = ord("L")
COM_STOPLOGGING = ord("F")
COM_GETLOGDATA = ord("R")
COM_GETCURRENTPOS = ord("Q")
COM_SETZEROPOS = ord("Z")
COM_SETPOS = ord("P")
COM_ENABLETHRESHOLDS = ord(";")
COM_SETPREFIX = ord("I")
COM_SETTHRESHOLDS = ord("T")
COM_SETWRAPPOINT = ord("W")
def __init__(self, serialport=None):
"""
Constructor of the RotaryEncoderModule object
A serial connection to the Rotary Encoder board is opened at the construction of the object.
:ivar str serialport: PC serial port where the module is connected
"""
if serialport:
self.open(serialport)
def open(self, serialport):
"""
Opens a serial connection to the Rotary Encoder board.
:ivar str serialport: PC serial port where the module is connected
"""
self.arcom = ArCOM().open(serialport, 115200)
self.arcom.write_char(self.COM_HANDSHAKE)
if self.arcom.read_uint8() != 217:
raise Exception("Could not connect =( ")
def close(self):
"""
Closes the serial connection to the Rotary Encoder board.
"""
self.arcom.close()
def __pos_2_degrees(self, pos):
return round(((float(pos) / 512.0) * 180.0) * 10.0) / 10.0
def __degrees_2_pos(self, degrees):
return int(round((float(degrees) / 180.0) * 512.0, 0))
def enable_evt_transmission(self):
"""
Enables the transmission of threshold crossing events to the Bpod state machine.
"""
self.arcom.write_array([self.COM_TOGGLEEVTTRANSM, 1])
return self.arcom.read_uint8() == 1
def disable_evt_transmission(self):
"""
Disables the transmission of events.
"""
self.arcom.write_array([self.COM_TOGGLEEVTTRANSM, 0])
return self.arcom.read_uint8() == 1
def enable_module_outputstream(self):
"""
Enables the streaming of current position data directly to another Bpod module (e.g. DDS, AnalogOutput).
"""
self.arcom.write_array([self.COM_TOGGLEOUTPUTSTREAM, 1])
return self.arcom.read_uint8() == 1
def disable_module_outputstream(self):
"""
Disables the streaming of current position data directly to another Bpod module.
"""
self.arcom.write_array([self.COM_TOGGLEOUTPUTSTREAM, 0])
return self.arcom.read_uint8() == 1
def enable_stream(self):
"""
Enables the streaming of the position and the time measurements to the USB port.
"""
self.arcom.write_array([self.COM_TOGGLESTREAM, 1])
def disable_stream(self):
"""
Disables the streaming of the position and the time measurements to the USB port.
"""
self.arcom.write_array([self.COM_TOGGLESTREAM, 0])
def read_stream(self):
"""
Reads the data being streamed through the USB port.
"""
res = []
available = self.arcom.bytes_available()
if available > 1:
msg = self.arcom.read_bytes_array(available)
while len(msg) >= 7:
if msg[0] == b"P":
position = int.from_bytes(
b"".join(msg[1:3]), byteorder="little", signed=True
)
evt_time = (
float(
int.from_bytes(
b"".join(msg[3:7]), byteorder="little", signed=False
)
)
/ 1000.0
)
position_degrees = self.__pos_2_degrees(position)
res.append(["P", evt_time, position_degrees])
elif msg[0] == b"E":
origin = msg[1]
event = msg[2]
evt_time = (
float(
int.from_bytes(
b"".join(msg[3:7]), byteorder="little", signed=False
)
)
/ 1000.0
)
res.append(["E", evt_time, origin, event])
msg = msg[7:]
return res
def current_position(self):
"""
Retrieves the current position.
"""
self.arcom.write_array([self.COM_GETCURRENTPOS])
data_in_bytes = b"".join(self.arcom.read_bytes_array(2))
ticks = int.from_bytes(data_in_bytes, byteorder="little", signed=True)
return self.__pos_2_degrees(ticks)
def set_zero_position(self):
"""
Sets current rotary encoder position to zero.
"""
self.arcom.write_array([self.COM_SETZEROPOS])
def set_position(self, degrees):
"""
Sets the current position in degrees.
:ivar int degrees: current position in degrees.
"""
ticks = self.__degrees_2_pos(degrees)
data = ArduinoTypes.get_uint8_array([self.COM_SETPOS])
data += ticks.to_bytes(2, byteorder="little", signed=True)
self.arcom.write_array(data)
return self.arcom.read_uint8() == 1
def enable_thresholds(self, thresholds):
"""
Enables the thresholds.
:ivar list(boolean) thresholds: list of 6 booleans indicating which thresholds are active to trigger events.
"""
if len(thresholds) != 8:
raise Exception("Thresholds array has to be of length 8")
string = "".join(map(lambda x: str(int(x)), thresholds))
bits = int(string, 2)
self.arcom.write_array([self.COM_ENABLETHRESHOLDS, bits])
def enable_logging(self):
"""
Enables the logging to the SD Card.
"""
self.arcom.write_array([self.COM_STARTLOGGING])
def disable_logging(self):
"""
Disables the logging to the SD Card.
"""
self.arcom.write_array([self.COM_STOPLOGGING])
def get_logged_data(self):
"""
Retrieves the logged data in the SD Card.
"""
self.arcom.write_array([self.COM_GETLOGDATA])
msg = self.arcom.read_bytes_array(4)
n_logs = int.from_bytes(b"".join(msg), byteorder="little", signed=False)
data = []
for i in range(0, n_logs):
msg = self.arcom.read_bytes_array(8)
data_in_bytes = b"".join(msg)
position = int.from_bytes(
data_in_bytes[:4], byteorder="little", signed=True
)
evt_time = (
float(
int.from_bytes(data_in_bytes[4:], byteorder="little", signed=False)
)
/ 1000.0
)
position_degrees = self.__pos_2_degrees(position)
data.append((evt_time, position_degrees))
return data
def set_prefix(self, prefix):
"""
Sets 1-character prefix for module output stream.
:ivar char prefix: One character to be used as prefix.
"""
self.arcom.write_array([self.COM_SETPREFIX, prefix])
return self.arcom.read_uint8() == 1
def set_thresholds(self, thresholds):
"""
Sets the thresholds values to trigger the events.
:ivar list(int) thresholds: List, in maximum, of 6 thresholds to trigger events.
"""
data = ArduinoTypes.get_uint8_array([self.COM_SETTHRESHOLDS, len(thresholds)])
data += ArduinoTypes.get_uint16_array(
[self.__degrees_2_pos(thresh) for thresh in thresholds]
)
self.arcom.write_array(data)
return self.arcom.read_uint8() == 1
def set_wrappoint(self, wrap_point):
"""
Sets wrap point (number of tics in a half-rotation)
:ivar int wrap_point: number of tics in a half-rotation.
"""
ticks = self.__degrees_2_pos(wrap_point)
self.arcom.write_array([self.COM_SETWRAPPOINT] + [ticks])
return self.arcom.read_uint8() == 1
if __name__ == "__main__":
import time
port = "/dev/tty.usbmodem69660901"
rotary_encoder = RotaryEncoderModule(port)
rotary_encoder.enable_logging()
time.sleep(5)
rotary_encoder.disable_logging()
print(rotary_encoder.get_logged_data())
rotary_encoder.set_zero_position()
rotary_encoder.enable_stream()
count = 0
while count < 10000:
data = rotary_encoder.read_stream()
if len(data) == 0:
continue
print(data)
count += 1
rotary_encoder.disable_stream()
rotary_encoder.close()
When I turn the rotary encoder anti-clockwise I get a lot of messages and the angle of the encoder printed correctly. But when I turn the encoder clockwise, I get maybe 10x fewer messages printed, and the angle is not updated correctly. I have re-stripped the wires of the pins and they are all inserted correctly. I can see no obvious issues or damage to the rotary encoder or the module.
Any help you're able to provide would be appreciated!
