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Connect servo motor with msp430


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Captain pedantic here.

 

1) The link you provide is a regular motor, not a servo motor -- continuous rotation, no positional feedback. Your choice of driver will depend on how much current. The no load current of your motor is rather low so can be done with a "jelly bean" transistor but the stall current is 0.5 A. If you be driving your motors with this much current, need a power transistor. Your motor drive circuit will also depend on whether you want one directional rotation or bidirectional-- single transistor (or Darlington) or H bridge. Don't forget the flyback diodes to protect your transistors.

 

2) True servo motors use a rotary encoder to provide positional feedback which is then used to position the motor. You need a dedicated servo motor driver to use one of these. Rather expensive but have great torque. Continuous rotation.

 

3) Hobby servos (very different from true servo motors) take a pulse width modulated signal and turns through a range of ~180 degrees. They can be modified for continuous rotation. Inexpensive, not bad performance, easy to interface to micro controllers.

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Wrong title topic. Must be a regular motor. I want to rotate back and forth.

 

Any Arduino tutorial will apply to MSP430 and Energia as well (except when they use dedicated motor driver shields). E.g. this one seems to be generic enough:

http://www.jeremyblum.com/2011/01/31/arduino-tutorial-5-motors-and-transistors/

Thanks a lot for the link.

 

 

Captain pedantic here.

 

1) The link you provide is a regular motor, not a servo motor -- continuous rotation, no positional feedback. Your choice of driver will depend on how much current. The no load current of your motor is rather low so can be done with a "jelly bean" transistor but the stall current is 0.5 A. If you be driving your motors with this much current, need a power transistor. Your motor drive circuit will also depend on whether you want one directional rotation or bidirectional-- single transistor (or Darlington) or H bridge. Don't forget the flyback diodes to protect your transistors.

 

2) True servo motors use a rotary encoder to provide positional feedback which is then used to position the motor. You need a dedicated servo motor driver to use one of these. Rather expensive but have great torque. Continuous rotation.

 

3) Hobby servos (very different from true servo motors) take a pulse width modulated signal and turns through a range of ~180 degrees. They can be modified for continuous rotation. Inexpensive, not bad performance, easy to interface to micro controllers.


I looked at the DC motor and my question is if I want to hook up bike with a larger current. For example, 0.8?. What do I need to add or replace. Apologies for dumb questions, but I'm new in terms of electrical engineering.

 

Thanks for your understanding.
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Please don't take this the wrong way, but if you are asking for guidance as to which transistors to use with a 0.8A motor, it doesn't sound like you are confident designing with discrete components, so I'd recommend you use the simpler approach of a H-Bridge IC such as the L293.

 

Designing a traditional H-Bridge with transistors is fairly straightforward, however in this case where you are using a 12V motor switched by a 3.3V microcontroller, it does complicate things a little, and requires at least 2 extra transistors to drive the top of the bridge. Depending on the current gains of your power transistors you may also need another 2 transistors to deliver adequate gain to the bottom of your bridge, and by now you are probably in a similar price bracket to an L293 anyway.  

 

The only difficulty with an L293 is that it needs a 5V power supply. It is quite happy to accept the MSP430's 3.3V logic though, so you don't have to worry about level shifting.

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Well is something like reading from where I can learn how things work? I understand you correctly, but I want to see more closely how things work, then you will tie the motor. Come on show me how can I find and forward to know how to calculate these things.

I am not sure exactly what you are asking but I agree with graham above about using an integrated motor driver-- perhaps a L298. You can get a breakout board from dx.com for ~$5-10. Works with 3.3V logic, two bridges (can control 2 motors), 2 A per bridge. Depending on where you are, you can also get other motor driver breakout boards from sparkfun.com, adafruit.com, pololu.com,etc.

 

Given how inexpensive they are, I would just buy one and see what happens. Other option is buying the motor first and seeing what the worst case current draws are and then purchase your motor driver based on the measured current draw.

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I'm happy to write a tutorial for using bipolar transistors, but you'll have to wait a few days for me to get time to do it properly. In the meantime I'm sure there's something kicking around on the web, maybe try something like "bipolar transistor tutorial" in google.

 

 

Sent from my iPad using Tapatalk

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I'm happy to write a tutorial for using bipolar transistors, but you'll have to wait a few days for me to get time to do it properly. In the meantime I'm sure there's something kicking around on the web, maybe try something like "bipolar transistor tutorial" in google.

 

 

Sent from my iPad using Tapatalk

 

Thank you very much. I will read for bipolar transistors. You do not need to write, as there is material on the Internet and I will read them. I would be grateful to direct me what to read, so I can figure out how to hook up the scheme with a larger motor. Thanks again:)

 

I would be very happy if you give me more material to an understanding of this scheme.

 

post-35922-0-58001800-1391086352_thumb.png

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Thank you very much. I will read for bipolar transistors. You do not need to write, as there is material on the Internet and I will read them. I would be grateful to direct me what to read, so I can figure out how to hook up the scheme with a larger motor. Thanks again:)

 

I would be very happy if you give me more material to an understanding of this scheme.

 

attachicon.gifDC Motor and Transistor.png

The schematic above will only drive the motor in one direction. If you need the motor to turn in both directions, you need to us an H bridge. I would suggest using an integrated motor driver such as an L298. I suggest looking at the data sheet for the device and going from there.

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