hey,
i wanted to build the dc motor control circuit as described http://itp.nyu.edu/physcomp/Labs/DCMotorControl.
since i couldn’t get my hands on a L293D i ordered a L293E instead since they seemed to be pretty much the same, except for the additional sensing resistors. now i received the parts and built the circuit - and it doesnt work at all =/
while all connections etc seem to be just fine, the motor doesnt move. now i was wondering if someone could tell me what those sensing registers actually are? this way i could probably figure out where the problem is… the datasheet says:
“Additionally, the L293E has external connection of sensing resistors, for switchmode control.”
i’m really new to this, thus i don’t know what switchmode control means…
to test the circuit i simplified the code to
digitalWrite(motor1Pin, HIGH);
digitalWrite(motor2Pin, LOW);
the strange thing is that when i apply the multimeter in voltage reading setting to the the specified INPUT pins and the L293s GND it prints the expected voltage (~9V and 0V), yet the OUTPUT pins on the L293E both read ~5v…
after i noticed this i took my power supplies GND and applied directly to the motor, which made it run. when i switch HIGH and LOW in the code, i have to apply the power supplies GND to the other power input on the motor, so this seems to be ok…
here is a picture:
your help is greatly appreciated…
best regards,
garnitchique