fischertechnik COMPUTING ROBO MOBILE SET 8 Mode D'emploi page 37

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O B O O B I L E E T C T I V I T Y O O K L E T
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While polarity plays no role in connecting a motor or pushbutton sensor (in the worst case the motor will
rotate in the wrong direction) it is vital for the function of the phototransistor to connect it correctly.
The contact of the transistor with the red marking should be connected to the red connector and the
other contact with the green connector. The second green connector belongs into the socket of the input
terminal AX that is located closer to the edge of the Interface. The second red connector fits into the
socket of AX that is located further on the inside. (Attention: When connecting the phototransistor to a
Phototransistor
digital input terminal I1-I8 the red connector needs to go into the socket located closer to the edge of
the case.
Now we can vary the intensity of the light
of the phototransistor using a flashlight.
This will change the reading of the blue
bar of AX. If the indicator does not move
from its maximum position we should take
another look at the connections of the
phototransistor. If however the indicator
remains at zero even with the flashlight
turned off it is possible that the lighting in
the room, the ambient light, is too bright.
The position of the bar will change when
we cover the phototransistor.
To come back to the color-coding of the
connectors again: During assembly we
will always be sure to connect the red
connector to the red wire and the green connector to the green wire. If the right polarity is important for
the circuitry layout we will always choose a red wire for the positive pole and a green wire for the
negative pole. While this might seem overly meticulous a clear color-coding makes systematic
troubleshooting that much easier.
A simple program will round out our first steps in the area of robotics. The program
"Garage Door Control System", explained in chapter 3 of the ROBO Pro manual
might have nothing to do with mobile robots but it is an excellent way to get to know
the ROBO Pro software. Only the motor and three pushbutton sensors from the ROBO
Mobile Set need to be connected to the Interface in order to recreate that program. Everything
else is described in detail in the software manual.
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