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16  Using Arduino / Motors, Mechanics, and Power / Re: Controling a 3.6V 1.2A Unipolar stepper motor on: June 24, 2013, 09:48:01 pm
This program is supposed to turn the motor 100 steps in one direction, this should be a half turn if your STEPS define is correct, then another half turn in the opposite direction, wait a bit and do it again.

Have a look at the definition Stepper stepper(STEPS, 8, 9, 10, 11);
if it isn't the same in the other program that works, just use the same settings.
17  Using Arduino / Motors, Mechanics, and Power / Re: Controling a 3.6V 1.2A Unipolar stepper motor on: June 23, 2013, 09:34:46 pm
Yes you can connect darlingtons in parallel but you better get bigger ones instead (unless you have a few unused ones of course).

And you HAVE to use an external supply, the arduino cannot push the current needed for your motor.
18  Using Arduino / Motors, Mechanics, and Power / Re: Controling a 3.6V 1.2A Unipolar stepper motor on: June 23, 2013, 08:41:49 am
If you're using simple transistors in unipolar mode, you must use a supply that'll deliver the exact needed voltage (if using darlingtons, voltage across the transistor could be 1.5V so a 5V supply would work)
If you're using a stepper driver then you can use a 12V or more supply, the driver chops the input voltage to limit the current to a desired value.
Using a driver (like the Pololu DRV8825) is recommended if you want the best performances (speed/torque) but it really depends on what you want to achieve.
19  Using Arduino / Motors, Mechanics, and Power / Re: Controling a 3.6V 1.2A Unipolar stepper motor on: June 21, 2013, 06:32:42 pm
You will need an external supply, the arduino onboard regulator cannot provide 2.4A (max current when both phases are on), nor does the USB port.

If you want to use this motor in unipolar mode you can just drive each phase with a darlington (just like with an uln2003) or fet.
If you want to drive it like a bipolar motor you'll need a driver like a Pololu DRV8825 (or a Gecko G250X, that's more expensive but professional quality)
20  Using Arduino / Motors, Mechanics, and Power / Re: Half Stepping with Arduino Motor Shield r3 on: May 20, 2013, 10:26:44 am
What is the motor shield you're using?

It looks like this shield input only has direction and step input, you don't need to use the stepper library. You only need to set the direction and send pulses on the pwm input to make your motor move.

But maybe you can set the stepping mode with jumpers on your shield, some allow setting to full, half or even microstepping.

The arduino stepper library is only needed if you directly drive an H bridge for a bipolar motor or transistors for an unipolar motor.
21  Using Arduino / Motors, Mechanics, and Power / Re: Arduino restarts when DC motors are turned on on: May 15, 2013, 02:09:22 pm
try 100 or 220 uF

Well you've got a problem because the 7809 is supposed to regulate a voltage higher than 11V to 9V but you're feeding it 7.5V, you could remove it completely since it's just in the way.

And I dont't think the L298 has flywheel diodes, did you add some?
22  Using Arduino / Motors, Mechanics, and Power / Re: Arduino restarts when DC motors are turned on on: May 15, 2013, 10:44:13 am
Yes try a big capacitor on the motor supply rail.
You say your supply is 7.5V but you use a 7809 regulator, do you have a DC/DC converter somewhere to convert the 7.5V to something greater than 9V to feed the regulator?
23  Using Arduino / Displays / Re: char to int problem. on: April 30, 2013, 12:12:08 pm
use print instead of write
24  Using Arduino / Motors, Mechanics, and Power / Re: Stepper Motor Basics on: April 27, 2013, 09:50:53 pm
Try lower speeds, 180 rotations per minutes @4096 steps/rotations gives 12KHz pulses, that may be too fast for your stuff, on an ebay page I found, it's written to start at maximum 500Hz and don't increase past 900Hz.
That's quite low, it means you should use 1/10 rotation per second or 6 rpm, maybe 12rpm will work if the load is light.
25  Using Arduino / Motors, Mechanics, and Power / Re: Stepper Motor Basics on: April 27, 2013, 09:31:40 pm
AFAIK the steps/rev is only used to set the speed.

Are you using half steps or full steps? The datasheet I found gives instructions to drive 1 or 2 phases (half steps) so it seems they mean 5.625/64 degree in half step mode and it's quite normal you're getting 2 revolutions if you're using full steps.

It's not the first time I hear about problems when using a high value in the stepper initialization, I'll have a look at the library.
26  Using Arduino / General Electronics / Re: Power supply outputs 0mA ?? on: April 25, 2013, 10:30:55 am
The 9V one that outputs 16VDC is probably not regulated, just a transformer with a diode bridge and maybe a capacitor, the voltage will drop, the more when more current is drawn.
27  Using Arduino / Displays / Re: Multiplex a HD44780 20x2 LCD display on: April 19, 2013, 11:10:13 am
There's already the enable pin that acts as a chip select for the LCD, all other pins can be shared without any changes if you don't read from the LCD.
You can connect all the pins going to the LCD (apart from enable) to something else and the LCD will ignore their state as long as the enable pin is kept High.
Of course you'll need another chip select to not mess the other stuff when sending data to the LCD.
28  Using Arduino / Displays / Re: is there a smaller than 8x2 LCD Module available for use with arduino hardware ? on: April 19, 2013, 11:04:22 am
Or use custom characters to simulate 4x size characters, I posted something like that some time ago:

http://arduino.cc/forum/index.php/topic,150227.msg1128016.html#msg1128016
29  Using Arduino / General Electronics / Re: Connecting PSX controller to Atari Lynx works but potential problem... on: April 17, 2013, 01:39:52 pm
what about adding a resistor between the arduino and the lynx?
30  Using Arduino / Displays / Re: Iteadstudio 16X2 Serial LCD Problem on: April 14, 2013, 08:10:35 pm
What about Serial.print(celsius);?
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