Show Posts
Pages: 1 ... 20 21 [22]
316  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Hooking up a 3.15v stepper motor, posible? on: August 29, 2008, 11:26:44 am
I just found one thing out while playing around the other day....  They have NO facility built-in to prevent back-flow of energy when turned off.

So, be careful about "spinning" your stepper when power is off.  It will turn into a generator and send power to your arduino through its pins.  (I was checking a wobble I had in a drive shaft, and noticed my TX/RX lights coming on on the arduino board... =)

!c
317  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Hooking up a 3.15v stepper motor, posible? on: August 27, 2008, 12:47:26 pm
It's really easy to use, just hook up the A and B coils to the appropriately labeled inputs on the easydriver, the Vin and GND to the appropriate inputs, then one digital pin from the arduino to each of the STP (step) and DIR (direction) inputs.

Then, you just change the direction by digitalWrite()'ing HIGH or LOW to the DIR pin.

To make it perform one step, just write HIGH to the STP pin for about 3ms, and then bring it low.  It'll only make one step for each transition from low to high.

!c
318  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Hooking up a 3.15v stepper motor, posible? on: August 27, 2008, 10:04:54 am
I'll second the vote on the easydriver - I'm currently using 3 on my project.

As madworm pointed out, you really don't need any special voltage regulation, the driver chip will do it for you.

For example, I run two arduinos and three stepper motors (rated @ 6v/0.8A each) off one 12v/3A power supply.  I used the easydriver's current adjustment to tune down the motors to the exact amount of current necessary (well below the actual 800mA, which the easydriver cannot provide -- it's limited to 750mA, IIRC) to drive the load that each needs.

Be warned, the chips on the easydrivers can get quite hot, make sure to account for any ventilation needs.

!c
319  Forum 2005-2010 (read only) / Bar Sport / Re: servo-servo mechanicals on: January 29, 2009, 04:18:31 pm
Well, servo horns are cheap and easily replaceable, I wouldn't be too worried about destroying them.  Of course, you can always insert a small screw of larger diameter than the holes in the horn, and just let it thread its self into the plastic for a decent grip.

!c
320  Forum 2005-2010 (read only) / Bar Sport / Re: About "free samples" on: January 08, 2009, 06:19:36 pm
Quote
I want SparkFun, etc., to source a few thousand of these matrix driver packages (significantly less than $5 in quantity), so they can reduce the single-quantity pricing!

And miss out on at least $4 in profit?  Sheesh!

Would $9.50 be enough, or how about $8.99? =)

!c
321  Forum 2005-2010 (read only) / Bar Sport / Re: About "free samples" on: November 19, 2008, 02:12:32 pm
I don't think they care all that much - I just make something up. =)

!c
322  Forum 2005-2010 (read only) / Bar Sport / Re: off-the-shelf 12V 6A+ power supplies? on: December 09, 2008, 10:43:19 am
If you can go w/ 5A, here's an inexpensive one:
http://www.mini-box.com/60w-12v-5A-AC-DC-Power-Adapter

And here's a 6A for just a couple bucks more on eBay:

http://cgi.ebay.com/Power-Supply-Adapter-12-Volt-6-Amp-12V-6A-Standard_W0QQitemZ220309986046QQihZ012QQcategoryZ3697QQcmdZViewItem

!c
323  Forum 2005-2010 (read only) / Bar Sport / Re: Ambient Orb style casings on: July 23, 2008, 12:11:25 pm
Acrylic is _really_ easy to work with.  You can buy some 5/16ths or thinner acrylic, cut it with a jigsaw (easy) or, if thin enough, use a scorer (more difficult), and then use a chemical bond to connect the pieces.  I use two corner clamps to bind pieces together, and either epoxy (fast, look doesn't matter), or solvent weld (looks better, more difficult to do well) the pieces.  You could make a box like that in 20 minutes for just a few bucks.

!c
Pages: 1 ... 20 21 [22]