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Having problems with chip and DC motor and potentiometer and Arduino....

roineust

Jul 2, 2013
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Jul 2, 2013
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Hello!

I have tried to build the following circuit:

http://fritzing.org/projects/drive-motor-using-l293d-sn754410

I have used and copied all the same components and wiring - exactly (i think..).

But - the motor seems to be working at the same speed and is not turning slower or faster, as i turn the potentiometer in each direction.

i have thought of several possibilities, for what is going wrong:

1. maybe the guy in the Fritzing site, refers to a stepper motor and not to a regular DC motor and that changes the whole picture, since i am using a regular small DC motor?

2. At the beginning of wiring and connecting the whole circuit together, i made a mistake and at the channels that are supposed to get 5V (red wires), i connected about 11V instead (the power that i need at max for the motor), maybe i have damaged the chip this way?


That's it...i can't think of anything else...

Can anyone with some serious experience, help me understanding, step by step, what is going wrong here?


Thanks a lot!
 
Last edited:

davenn

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Sep 5, 2009
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Hi ya

no it looks like a standard motor steppers generally have 4 or more wires

OK we need to see photos of YOUR construction so we can compare it to the ones on that site and see if there are any wiring mistakes

if the Arduino got more than 5V you may have zapped it
and finally ... the bit I know nothing about, but I'm sure others can comment
Does the Arduino need programming ??

cheers
Dave
 

roineust

Jul 2, 2013
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Jul 2, 2013
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Hey Dave!
I have uploaded the code to the Arduino.

Can you please explain to me, wht should more than 5V fry the Arduino?
I have made several google search for the keywords "Arduino voltage" and always got the answer 5-12V (or 3-12V, depending on the model) ??

I will try to check out if the Arduino is still functional...
 

roineust

Jul 2, 2013
30
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Jul 2, 2013
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Hey Dave!
Thanks!
Your were right! I have fried the Ardu! Just as soon as i replaced it, everything started working well!

But yet, i have another small problem - when i turn the dial in such a way, that the motor goes very slow, if at that state, i shut the whole system off (while the motor is going very slow), using a toggle switch i have there, then, even if i turn the dial back to faster motor speed - it doesn't help, and the motor won't move and only does these strange voices, as if it is trying the prime (it is hooked to a micropump) - the only thing that fixes this situation, is if i switch the wires going to the motor (+ and -) and thus switch polarity, and then the motor starts running again and then i can switch back to the right polarity and it works again!

Does anyone know what is the source of this problem? It can't be a priming problem, since it happens even if i turn the dial to high speed before turning the system back on and this situation does not solve until i switch polarity back and forth once.

I though, that maybe i can make the polarity switching process faster, by somehow hooking the motor + and -, after the place where the on\off toggle is located, using another toggle, the 6 legged type...is it possible to switch the DC motor polarity using one of these 6 legged type toggles ?? :

http://static3.tme.eu/katalog_pics/b/2/3/b23356a2bb2f77e81fb2c52eb0688a8d/ms500if.jpg


Thanks a lot, appreciate you help!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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At low speed, there may be sufficient torque to keep the motor going, but not to start it.

The answer may be to either limit the minimum speed to one where it can start, or to change the code so that it gives the motor a brief period at full speed before trying to run it at the low speed.
 
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