Hello,
I need guidance regarding the choice of hardware.
I need to command a step by step motor that will drive the focus of my camera objective.
I need the setup to be light, small but precise.
I think this is all I need :
- arduino board (or even the nano one)
- 9V battery
- step by step motor
- control command.
What motor would you advice me ? It does not have to have a lot of force.
What control can I use ? I thought about using midi controller but I wonder this is necessary, can I just use electric ones ? and then which one ? I guess I would prefer a wheel rather that two buttons or a joystick. The whole thing might be wired but any advice on HF would also be good.
Thanks a lot for your great help.
Alex
PaulS:
For what? Is the camera focus somehow related to music?
Not related to music no, I want to set the point of the focus of the camera with a motor. Instead of turning it by hand.
You need a stepper motor driver, if you are planning on driving a stepper motor. Midi controllers and relay controllers are not suitable substitutes.
Ok thanks for that info. But I meant a sort of physical wheel. I want the system to be independant. I don't want to control the motor from the computer.
What will this wheel, or two buttons, do?
Idealy I would like to turn the wheel to turn the focus. So If I turn the wheel 10° left, the motor will go backward to achive a 10° turn on the camera focus (I'd have to work on the scale but that does not have to be degree precise since I will do it visually)
What do you mean by HF? Until you get a lot more experience, stick with wires.
Sorry HF I meant wireless. So what kind of battery will I need ? Why is 9V not suitable because of amperage ?
This motor and this driver should be sufficient. The motor has the power to provide 2.5 ounces of force at 1 inch distance from the shaft. To interface to it you just need to set one line high or low to tell it what direction to turn and then pulse a second line for each step you want it to move.
A 9V battery has a capacity of about 400mah (400 milliamps over the course of one hour). This motor pulls 600ma, so with active use your 9V battery would only last an evening or so. A small sealed lead acid battery would probably be best.
The type of control you're looking for -- a type of knob you could spin continuously -- would be referred to as a rotary encoder. Offhand I'm not aware of any that are low cost with enough resolution for a project like yours.