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2491  Forum 2005-2010 (read only) / Bar Sport / Re: Best way of creating your own pcbs on: November 23, 2009, 08:09:34 am
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The best thing is to use paper from commercials (spam) that you get to your mailbox).
The best thing to use is Press-n-Peel Blue, which is designed for the purpose, but costs about US$2 for an 8.5"x11" sheet.

-j
2492  Forum 2005-2010 (read only) / Bar Sport / Re: Best way of creating your own pcbs on: November 17, 2009, 02:59:40 pm
The "special paper" has a coating.  The toner bonds to the coating (else it would make a huge mess out of your printer), but the toner+coating releases easily from the backing material after you re-heat the toner and stick it to the copper.

-j
2493  Forum 2005-2010 (read only) / Bar Sport / Re: Simple Code Optimizations on: October 27, 2009, 04:45:50 pm
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So instead of:

word i = 25000;

i /= 256;

You would use

i >> 8;

Modern compilers will identify the former and optimize it into the latter, if given sufficient leeway via the optimization level flag.

-j
2494  Forum 2005-2010 (read only) / Bar Sport / Re: Simple Code Optimizations on: October 14, 2009, 06:54:44 am
Something I was taught in CS class years ago that I've found to hold true:

when writing code, make it:

     1 correct
     2 easy to understand (and therefore easier to maintain)

Performance comes last.  Only worry about performance if you find there is a performance problem when executing your correct, clearly written code.

As westfw says, you can just write the code and let the compiler work its magic.  (I suspect black magic at high optimization levels.  smiley )

-j
2495  Forum 2005-2010 (read only) / Bar Sport / Re: CHANGE IT ALREADY! Support needed! on: October 21, 2009, 08:42:36 pm
Maybe we're being DoSed by microsoft?  The forum home page says:

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Most Search Engines ever online was 111 on Today at 5:38pm.

and:

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Users Online
...
Search Engines: 68
Yahoo! Crawler (2), MSN Search (65), Googlebot (1)

Why does MSN Search need 65 bots crawling the server????

-j
2496  Forum 2005-2010 (read only) / Bar Sport / Re: Suggestion for 3.3 volts on: September 10, 2009, 06:20:30 pm
The standard TO-330 sized LM series (you'll be wanting the 7833) are generally capable of 1A.

The LM317 adjustable regulator is capable of 1.5A.  It's a different pinout than the 78xx and you'll need a pair of resistors to set the output voltage (google lm317 calculator for help with that).

You refer to a switcher; all these I mention are linear regulators, so if you're very worried about efficiency or heat dissipation keep looking.  smiley

-j
2497  Forum 2005-2010 (read only) / Bar Sport / Re: Eagle printing resolution? on: August 20, 2009, 11:25:19 am
It didn't occur to me to look for postscript output in the CAM processor.  Using the CAM processor's PS device did the trick!  now I hope my toner transfer/etch fab process (and skills) are up to the task. smiley

thanks!

-j
2498  Forum 2005-2010 (read only) / Bar Sport / Re: Eagle printing resolution? on: August 19, 2009, 08:28:47 am
I thought about that, but I've had problems getting 1:1 in the past, so I thought I'd try to find a way to make eagle do what I want.

I may have to generate gerbers and use a gerber tool of some sort to print it.

-j
2499  Forum 2005-2010 (read only) / Bar Sport / Eagle printing resolution? on: August 18, 2009, 08:15:18 pm
I'm using the latest Mac version of eagle.  I've got some smaller pitched devices that come out as a single blob when I print the board layout on an HP laser printer (1200 dpi).  I can't find a setting to influence this.

Any clues on how to increase the print resolution?

-j
2500  Forum 2005-2010 (read only) / Bar Sport / Re: dirt cheap PCB manufacture on: August 09, 2009, 07:22:24 am
Yep, the ExpressPCB software definitely sucks bigtime, and it's windows only.

I hope to try batchpcb soon.

-j
2501  Forum 2005-2010 (read only) / Bar Sport / Re: HMC6352 compass in a vehicle? on: May 31, 2009, 07:33:33 pm
Thanks for the pointers to the app note and the new device.  I'm in no hurry, so it won't kill me to wait for it.  

The app note leads me to believe that the calculations are simpler than I would have guessed.  Not sure why, but I was envisioning some calculus.  smiley

-j

2502  Forum 2005-2010 (read only) / Bar Sport / Re: HMC6352 compass in a vehicle? on: May 31, 2009, 05:28:13 pm
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The HMC6343 (which has a third axis and accelerometers) does do a good job
at compensating for tilt.

I don't doubt it, but even the HMC6352 is more expensive than a cheap GPS; the HMC6343 is well out of the budget for my application right now.

The Garmin GPS units (especially the GPS18) do a pretty good job of maintaining a sane heading indication, even at low speeds or when stopped (got to allow for moving in reverse, though).  I'm not sure the expense ($US50) is even worth it for the HMC6352.

-j

2503  Forum 2005-2010 (read only) / Bar Sport / HMC6352 compass in a vehicle? on: May 31, 2009, 12:07:35 pm
Has anyone tried using a HMC6352 compass mounted in (or on) a vehicle?  Does it compensate for all that metal, and how bad are the measurements when on an incline?

thanks.

-j

2504  Forum 2005-2010 (read only) / Bar Sport / Re: Part suggestions needed on: May 18, 2009, 06:15:32 am
The MCP3208 is an 8 channel ADC, and it's trivial to run 2 of them.  code for it is in the playground, and I posted code for using multiple units on the forum a few days ago.

-j

2505  Forum 2005-2010 (read only) / Bar Sport / Re: Ciao a tutti on: April 15, 2009, 05:34:51 am
well, the description for "bar sport" says "any language"...

-j

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