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1  Using Arduino / Project Guidance / Re: Spacer / Standoff Mounting Suggestions on: February 10, 2013, 09:09:58 am
I use 6-24 "bolts" and nuts for all of my hardware. Just one size / thread to keep track of. Think about short lengths of wood dowel rods.  Inexpensive, easy to cut to length, and insulated . Drill a pilot hole and use the 6-24 to connect.
2  Using Arduino / Project Guidance / Re: What is the difference between a MOSFET and a TRIAC? on: October 02, 2012, 04:36:16 pm
dhenry - Thanks for a nice concise explanation.

CrossRoads - Thanks for nothing. When I googled, I got several seemingly conflicting pieces of information. One was that a triac is AC only. One was that a triac is isolated from the controller. One was that the triac was not isolated from the controller. ANd one was my original question. I was hoping that this group would have a nice concise answer from a group of intelligent electronics experimenters, which it did.

The problem with the internet in general is that there is a lot of misinformation out there, and if you are not an expert it may be hard to separate the wheat from the chaff. Fortunately this forum is able to do that. With a rare exception or two.
3  Using Arduino / Project Guidance / Re: data logging/processing on: October 02, 2012, 03:48:25 pm
I like the idea of attacking a large project as a series of tiny steps. I also agree with everyone on logging the data to an sd card. You do need to be able to time stamp each event, however, if you want to be able to do time series analysis. So that is one more step to accomplish.

The place to do the data manipulation  is on a PC (or Mac). You have many more tools available.

If you don't want to use the ethernet card to post the data, just remove the card, download the data to an SQL table, erase the file, and reinsert the data card. Or have two cards to swap back and forth.

You may want to use a spreadsheet first as a proof of concept. Then migrate the data to a database later, as another step.

If you are squeemish about the data analysis side there are people here to help you. I would even volunteer.
4  Using Arduino / Project Guidance / What is the difference between a MOSFET and a TRIAC? on: October 02, 2012, 03:21:10 pm
I am a noobie at electronics and thought I understood MOSFET's and how they work. Then someone said they were using a DIAC and a TRIAC in a sped controller. They looked like they were performing the same function as a MOSFET. Can someone enlighten me (gently)?
5  Using Arduino / Project Guidance / Re: How To Make Servo Brackets Like Those On Lynxmotion Robots? on: October 02, 2012, 02:53:47 pm
They look like bent metal. The easiest way would be to get some sheet aluminum, preferably from a scrap yard. make a small wood block  the size of the interior space and bend the aluminum around it.

If you are going to do a number of these, think about making a simple brake to make the bend uniform. This can be made from a sjort piece of angle iron and a couple of hinges.  A handle on the side will give you some leverage. Here is a link:

http://blog.makezine.com/2011/12/07/bending-aluminum-enclosures-on-a-homemade-brake/

Make a little jig to rotate the bent bracket against a grinding wheel to give you the rounded corners.

Do a production run since setting up the jigs will take a bunch of time. Doing one may take five minutes, but the second one will be 15 seconds.

6  Using Arduino / Motors, Mechanics, and Power / Re: Help with AC motor from turntable on: May 05, 2012, 09:11:57 pm
Is it  a direct drive motor or is there a gear drive / belt drive? If the latter, it would be an easier alternative.
7  Using Arduino / Motors, Mechanics, and Power / Has anyone experimented with a Minn Kota motor? on: May 05, 2012, 08:51:11 pm
Has anyone used their arduino to control a Minn Kota trolling motor? I have a pair of motors with hacked controllers. The "soft pot" on the controllers seem to be fried, and I am looking to use the majority of the minn kota controller with a differant input. I am hoping someone has attacked this problem.
8  Using Arduino / Motors, Mechanics, and Power / Re: arduino external power supply on: May 05, 2012, 08:48:04 pm
The 9 volt can supply he arduino alone. The other batteries should power the motors. The 9 volt will not be enough to poer both.
9  Using Arduino / Project Guidance / Re: Investigating project feasibilty - a question on shields on: May 05, 2012, 04:38:25 pm
Shields normally cover the arduino, for space limitations. Some shields have headers on only one side, so they can be used as a "wing", where the shield sits alongside (and above) the arduino. The header's pins form a serial pass through for the pins below. So if you cover pin 8 (for example) on the arduino, plug your component into pin 8 on the shield and you still have connectivity.
10  Using Arduino / Project Guidance / Re: Inconsistent Running motors? on: May 05, 2012, 11:33:22 am
In your reverse module I would switch the order of the writes. Set one low before setting the other high. Otherwise you momentarily have both pins set high. May not be a problem, but it might solve one.
11  Forum 2005-2010 (read only) / Interfacing / Large DC motor control on: March 22, 2010, 10:34:49 pm
I am new to micro controllers. My project is to control a pair of trolling motors independantly on an electric boat. It seems that an arduino can supply the logic to set the speed, but I need a motor shield, or a large capacity H bridge (which may be the same thing). Can anyone piojnt me toward a shield that could control a pair of 12 v 20 amp motors?

George
Conway, SC
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