Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: regaljohnston on January 26, 2013, 06:32:07 PM
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hi,
this it's my first project, and a good starting point for the pursuing animatronics, which i am very much interested in for video.
all you really need to know is that i am trying to:
-make a motor rotate between a range of low speeds, clockwise and anti-clockwise based on the signal from a potentiometer, or some other controller.
this is to control the zoom ring on my camcorder's lens.
it needs to:
-be as quiet as possible (for obvious recording reasons).
-have a variety of speeds.
-ease in and out of zoom smoothly/seamlessly.
-have a control which is operably by my thumb alone, a left/right thumb-stick or a seasaw peddle would be ideal.
i am new to all this so please bare with me, i am trying my hardest but would greatly appreciate any advice/guidance/direction.
please help me, let me know what your approach would be.
thanks!
regal johnston...
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somebody on another forum has since suggested "building a DIY motor control based on an Arduino" to solve my problem.
what is my best course of action?
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You could use an Arduino (or Axon ofcourse). This is a little guess, as of your conditions, but a stepmotor could provide the accuracy, and certain models are even moderate speed (more speed less torque), but never really high speed. Then you need a good motor driver that can handle the amps.
A WII nunchuk could do the trick for controlling or even an old ps2 conroller.
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that's the most helpful advice i've had yet, very specific.
a few people have suggested step motors to me... that seems like the route to take.
could you suggest a good one for me? or point me in the right direction.
and as for an arduino... could i use the arduino UNO to do this?
i figure the best way to move forward is to buy the parts i need and start working on them/figuring them out.
is that everything i will need? a stepmotor, a wii nunchuk/ps control and an UNO arduino?
thanks a bunch, very helpful.
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Yes the Uno could do this, do not forget the motor-driver-board. The stepmotor depends on the power (make sure the motordriver can handle the motor even when it needs a fair amount of power) thats need to rotate the parts.
For more specific parts we need more details and know how much force is needed to move the object you want to move.
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Using Arduino, motor driver and stepper motor is an overkill with capital O ;D
To achieve what You want it is enough to have microcontroller with 1 ADC (analog to digital) port to read potentiometer value and 1 PWM port to drive the motor. Something small and cheap like Atmel ATtiny13A (http://www.ebay.co.uk/itm/Atmel-ATtiny13A-8-bit-20MHz-1kB-Flash-PicoPower-AVR-microcontroller-DIP-8-/271110237220?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3f1f6dec24&_uhb=1) is more than enough.
Stepper motor is a very bad choice for this application. Stepper motors are bulky, heavy and move in steps (hence the name), meaning You will not get smooth zoom, unless You are willing to develop/buy micro-stepping driver and algorithm. On top of all that, 1 stepper motor requires 2 H-bridges to run as opposed to 1 H-bridge for regular motor. Operating camera lens does not require a lot of torque, hence small geared motor or small servo is suitable to use. How quite these devices are depend on how much you are willing to spend.
Using full blown motor driver is an overkill as well. Get something like L298N (http://www.ebay.co.uk/itm/L298N-L298-Dual-Full-Bridge-Dirver-Power-IC-ST-ZIP-15-New-858-UK-SELLER-/221173801497?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item337efc6219&_uhb=1) - plenty to drive small motor.
As for thumb stick - Thumb Button Analog Joystick Stick for Sony PSP 2000 Pink UK (http://www.ebay.co.uk/itm/Thumb-Button-Analog-Joystick-Stick-for-Sony-PSP-2000-Pink-UK-/370744418586?pt=UK_VG_Replacement_Parts_Tools&hash=item565216e11a&_uhb=1).