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1  Using Arduino / Sensors / Re: Contact Sensor on: August 06, 2012, 11:29:02 am
Mmm...those could work too.  The magnets in my example were only there to ensure a tight connection between 2 wires.  But sounds like I could use these magnet sensors to eliminate the need for the pieces to even touch.  Which would actually be better because another concern was trying to figure out was which way to "unravel" seeing how I'd have to temporarily disable the fail safe to see which direction would disconnect the 2 wires.  But I could stop the screen before it reaches the sensor based on increased magnetism.  Then to figure out which direction, I could choose the direction that causes a decrease in magnetic detection.  Thanks Magician.
2  Using Arduino / Sensors / Re: Contact Sensor on: August 06, 2012, 10:50:27 am
Well the magnet wouldn't have contacts.  I'd have to make the contacts by wrapping the - & + wires around the 1st magnet w/ a gap.  The 2nd magnet would be covered in wires or a metal plate.  When the magnets touch, then - & + wires will be bridged sending a signal to my arduino.  I don't necessary have to use magnets.  I also thought about just having a metal plate at the bottom of the screen.  Then having just 2 wires sticking out (one from 5v from arduino, the other into a digital input).  When the metal plate touches the 2 wires, the connection will trigger me to shut off the motor.  I just liked the magnet idea a little better because the wires would be more stable & even if I was a few cm off, the magnets would attract each other & create a strong connection between the 2 wires.
3  Using Arduino / Sensors / Contact Sensor on: August 06, 2012, 10:05:32 am
I was being a little too cheap & opted for a motor w/o an encoder to roll a screen up & down.  I've noticed that depending on the wind, the screen unravels at different speeds.  This causes a huge issue for me because I have no idea how far it unravels.  Although I don't care as much about the unraveling, I do care about rolling the screen back up.  I can't roll it up above a certain height or it will basically tear itself apart.  I've decided the best course of action (besides breaking down & purchasing the same motor w/ the encoder) is to add a contact sensor.  I was thinking about using 2 small/weak magnets (w/ plastic coats) to make sure the contacts line up well.  I was going to wrap the max height sensor w/ the + & - leads separated with a small gap.  Then I was going to wrap the screen sensor with lots of wires going in every direction.  That way no matter how the magnets touch, they will bridge the gap.  Any thoughts?  Anyone have a better example?  Or even something I can purchase online?  Thanks.
4  Using Arduino / Motors, Mechanics, and Power / Re: NTE7064 + 9-18VDC Motor on: June 30, 2012, 09:42:26 pm
Just to update.  Here is the project in action (but not exactly complete yet).  After seeing the radioshack motor in person, it wasn't going to handle near the load I needed it to.  I purchased the largest motor I could find on Pololu that could take the most torque.  I also bought a new motor carrier that could support the 5A max stall from the new motor.  First time soldering - definitely an art.  Working great.  Arduino isn't as scary as it looks =P

http://imgur.com/a/MUOVD#1 (here's the album)

5  Using Arduino / Motors, Mechanics, and Power / Re: NTE7064 + 9-18VDC Motor on: June 06, 2012, 07:14:28 pm
Thanks for the reply.  That definitely eases my mind about my gameplan.  I hadn't really thought about the gears much.  Are gears difficult to find?  Will the motor come with a standard size gear I can attach a larger gear to?  I guess I'll find out some of that sooner than later.

Here's the schematic.



6  Using Arduino / Motors, Mechanics, and Power / NTE7064 + 9-18VDC Motor on: June 05, 2012, 07:43:39 pm
So I'm trying to build a large automatic window shade (8ft by 16ft).  The shade will most likely just be a plastic tarp of some sort.  And the roller will be w/e metal bar I can find at Home Depot.

NTE7064 - http://www.radioshack.com/product/index.jsp?productId=12706338
9-18VDC Motor - http://www.radioshack.com/product/index.jsp?productId=2102827
Arduino Kit - http://www.makershed.com/Getting_Started_with_Arduino_Kit_V3_0_p/msgsa.htm

My questions are the following...

1) The datasheet shows Vcc & Vs pins.  Vcc = 5V from arduino board & Vs = 9-18V from power supply?
2) Will I need any resistors, diodes, or capacitors?  Or does the NTE7064 take cake of most of that?
3) The max arduino can take is 12V.  The NTE7064 avg current is 1A.
    a) Will that be enough to roll a 8'x16' plastic tarp up & down?  Or should I bypass the arduino board & power the NTE7064 directly w/ 18V?
    b) Can my breadboard & 22 AWG wires from the Arduino kit handle an avg 1A of current?
    c) Assuming 12V & 1A avg will be enough, does that mean I need a 12v 1A power supply?

Thanks in advance.
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