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Author Topic: CNC Sewing Machine with Arduino - is it possible  (Read 505 times)
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Hi,

I am looking at the feasiblilty of adding an XY table to my sewing machine. It seems possible but wanted to make sure I could do the following:

1. Simulate a potentiometer - the machine uses a potentiometer to control the speed of the machine. I believe it is +5V and it will run full speed and I assume at +2.5V it will run at half speed. The physical potentiometer now obviously adds resistance and reduces the voltage to the drive board and in turn will reduce the speed of the motor. Can arduino send a voltage signal to the board to start and slowly ramp up the speed by increasing voltage slowly to a maximum of +5V?

2. I will be using servo motors to drive the XY table. I need to sync the speed of the XY table motors with the speed of the machine. Can I control the speed of the servo motors to gradually speed up at the same rate as I drive the machine using the method above? These need to be synced otherwise with a speed mismatch, the needle might be embedded in the fabric while the XY table is moving.

3. Are there freelance people who could write the program for me for a fee?

Thanks in advance for the help.

Henry
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Leighton Buzzard, UK
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I'd use stepper motors instead of servos
much more suitable

I've implemented stepper projects before
where are you based?
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You could simulate the behaviour of the manually-operated potentiometer either by using a digital potentiometer, or by using an external circuit to smooth a 5V PWM signal out to provide an analog voltage, or an external DAC. Or, you could use a Due, which I understand includes DAC capability.

If you want somebody to do the work for you and are willing to pay, the Gigs and Collaborations section is the best place to ask.
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I'm based in Hong Kong. Yes sorry I meant stepper motors, accuracy isn't really that important for me as I'm just sewing a 2" x 4" X onto a piece of velcro. I figure I would just save my sewing ladies hands from Carpal tunnel and automate the process smiley

I think the digital potentiometer will do the trick. Seems simple enough and I'm not really worried about efficiency so don't necessarily want to go down the PWM route. I guess the question with the digital potentiometer is can I vary the resistance (ie. voltage) and syncronise it with the speed movement of the XY table? So, if the sewing machine sews slower, the XY table moves slower and if the machine sews faster, the XY table sews faster.
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I think the digital potentiometer will do the trick. Seems simple enough and I'm not really worried about efficiency so don't necessarily want to go down the PWM route. I guess the question with the digital potentiometer is can I vary the resistance (ie. voltage) and syncronise it with the speed movement of the XY table? So, if the sewing machine sews slower, the XY table moves slower and if the machine sews faster, the XY table sews faster.
Couldn't you just put a sensor (IR, hall effect etc) to detect the position of the needle bar? That way the single sensor would allow you to detect both the needle position (whether it's up or in the fabric) and sewing speed.

BTW what are you sewing? Just simple built-in machine stitches or more like the proper embroidery machines do? A friend of mine recently bought one of those machines and it's amazing what they can create.
« Last Edit: November 22, 2012, 03:12:58 pm by jabbado » Logged

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Yes a hall sensor would make perfect sense so I know the speed.

I am just doing simple stitches not embroidery. It's just a square box with a X stitch inside it.
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