getInfraredSensorSeek: 'float' object is not subscriptable #78
Description
Steps to reproduce
- On an EV3 running ev3dev-stretch-ev3-generic-2020-04-10 attach the LEGO EV3 IR sensor to sensor port 4.
- run this program (composed in ORL):
#!/usr/bin/python
from __future__ import absolute_import
from roberta.ev3 import Hal
from ev3dev import ev3 as ev3dev
import math
import os
class BreakOutOfALoop(Exception): pass
class ContinueLoop(Exception): pass
_brickConfiguration = {
'wheel-diameter': 5.6,
'track-width': 18.0,
'actors': {
},
'sensors': {
'4':Hal.makeInfraredSensor(ev3dev.INPUT_4),
},
}
hal = Hal(_brickConfiguration)
def run():
while not hal.isKeyPressed('escape'):
if hal.getInfraredSensorSeek('4')[0] > 0:
hal.drawText("Hallo", 0, 0)
else:
hal.drawText("Goodbye", 0, 0)
def main():
try:
run()
except Exception as e:
hal.drawText('Fehler im EV3', 0, 0)
hal.drawText(e.__class__.__name__, 0, 1)
hal.drawText(str(e), 0, 2)
hal.drawText('Press any key', 0, 4)
while not hal.isKeyPressed('any'): hal.waitFor(500)
raise
if __name__ == "__main__":
main()Expected result
The code should evaluate the first item in the list returned by getInfraredSensorSeek().
Actual result
getInfraredSensorSeek() seems to return a float.
This is the traceback:
robot@ev3dev:~$ ./lupo.py
Traceback (most recent call last):
File "./lupo.py", line 41, in <module>
main()
File "./lupo.py", line 31, in main
run()
File "./lupo.py", line 24, in run
if hal.getInfraredSensorSeek('4')[0] > 0:
TypeError: 'float' object is not subscriptableFurther information
Maybe #56 is related?
If I change the python code like this it works as expected:
24c24
< if hal.getInfraredSensorSeek('4')[0] > 0:
---
> if hal.getInfraredSensorSeek('4') > 0:If the beacon is left of the sensor (when looking from behind the sensor) the values are positive (up to 25?) else negative (down to -25?).
Further Questions
How is the sensor supposed to work? Is it similar to lejos getSeekMode?