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Topic: New Project Quick Question. Need Help. (Read 398 times) previous topic - next topic

Integ

What would I need to be able to use 5 Flex sensors and 5 stepper motors? I have the arduino uno. Do I need a mega? Thank you.

ByteLogic_inc

Hello,

I would think so, as you will need quite a lot of PWM pins to drive the stepper controllers. I would recommend using an arduino Mega, but an external chip that can add more PWM pins. A 74HC595 chip and follow this tutorial:

http://www.arduino.cc/en/Tutorial/ShiftOut

Sreeteja Jonnada,
ByteLogic Inc.

AlxDroidDev


What would I need to be able to use 5 Flex sensors and 5 stepper motors? I have the arduino uno. Do I need a mega? Thank you.


What are the specs of the steppers? How do you plan driving them? Directly or through an IC like the L293 or L298 (the most common) ?

I strongly advise on not using direct drive for the steppers. Even if they are low power, it is often best to use a motor driver IC.

If you choose to use a driver, you don't need a Mega. Instead, you'll need 5 driver ICs + 3 x 74HC595. That is much cheaper than buying a Mega, and you'll save a lot of pins in your arduino. You can drive all those steppers with only 3 pins.
Learn to live: Live to learn.
Showing off my work: http://arduino.cc/forum/index.php/topic,126197.0.html

Integ

I am planning on using this motor: http://www.ebay.com/itm/CNC-Nema17-Hybrid-Stepper-Motor-DC12V-04A-2-Phase-2600g-cm-34mm-4-Lead1-8-Degree-/161005993157?pt=LH_DefaultDomain_0&hash=item257cb47cc5 or something like that.

Would I also need these? http://dx.com/p/l298n-stepper-motor-driver-controller-board-for-arduino-120542
I am pretty new to this stuff so I need some guidance. My project is about making a robotic hand controlled by a glove with flex sensors attached.
Thank you.

PeterH

That driver looks like a reasonable spec to drive that type of stepper motor. You'd need one driver per stepper, and a power supply capable of supplying 5A or so at your desired voltage. Note that each stepper driver would require several Arduino pins so the total pin count will be quite high. Note the comments about the lack of documentation. It shouldn't be hard to work out how to use it, but you will probably have some figuring out to do.
I only provide help via the forum - please do not contact me for private consultancy.

Integ

How many pins would a stepper motor require? Also how would I go about coding. I want the motor to rotate every time the flex sensor bends. For instance when the hands is trying to make a fist the motor should start rotating till the fist is made. And when i am extending my fingers it should start to unwind. I am also at beginner level with arduino coding. I just need an example to start it off.
Thank you very much.

AlxDroidDev


Note that each stepper driver would require several Arduino pins so the total pin count will be quite high.


In theory you are right.

However, I'd take a look at the approach LadyAda had with her Motor Controller Shield: the shield has 2 x L293N, which would require 4 pins each from the Arduino. She, however, used a single 74HC595 to interface with the Arduino, and the 595 is in the shield.

Using the same approach, one can have up to 16 steppers, each one with its own driver, and each pair of dirvers controlled by one 74HC595. Since the 595 can cascade, they'll only take 3 pins in the Arduino.

So, using a $0.50 IC, which is the 595, you can "multiply" the number of output pins in the Arduino, but taking ip only 3 pins in the Arduino.
Learn to live: Live to learn.
Showing off my work: http://arduino.cc/forum/index.php/topic,126197.0.html

ByteLogic_inc

Couldn't you just use servos instead of steppers, it would remove the need of external chips. Unless you are making a super-strong robot that can lift 50kg on its little finger!!  ;)

Integ


Couldn't you just use servos instead of steppers, it would remove the need of external chips. Unless you are making a super-strong robot that can lift 50kg on its little finger!!  ;)

Haha thats the plan. For it to hold a lot of weight. Thanks fellas.

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