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1261  Community / Bar Sport / Re: What they teach in school. on: March 19, 2013, 12:57:11 am
I'm Gen X and yeah, we did have "group" projects in school but they were still fairly infrequent. But when you consider that the vast majority of schoolwork favors the introvert I think it's perfectly reasonable to structure some projects to favor extroverts.

I consider myself a "cynical introvert"; I like to listen to others and then try to rip up their theses. Sometimes I come to a conclusion that the solution is different than what is being put forward and sometimes I don't. That's just how I work, and without an extrovert's opinions to work from I don't think I'd work as well.
1262  Topics / Product Design / Re: Itead, Members with Experience... on: March 19, 2013, 12:29:50 am
Submitted my design with Seeed on 2/22. They marked it shipped on 2/28. Received in the mail 3/15.
1263  Using Arduino / Motors, Mechanics, and Power / Re: Car Battery power supply questions on: March 19, 2013, 12:22:56 am
There's always the option of the ~$2 car charger for USB devices that fits in the lighter socket.
1264  Using Arduino / Project Guidance / Re: Automated Chicken Coop Door on: March 18, 2013, 12:02:18 am
My take was to put spring-loaded lever switches under the roosts so when the chickens come in and roost the door closes a little while after. Much easier than adding a time-keeping chip; the chickens already have their own anyway.
1265  Using Arduino / Microcontrollers / Re: avr to breadboard help? on: March 18, 2013, 12:00:06 am
Add LEDs (plus appropriate resistors) on pins 7, 8, and 9 on the Uno. These will show the status of ArduinoISP, or at least provide a sanity check that you actually have ArduinoISP running on the board. Also check the output from "dmesg" to ensure your USB connection to the Arduino isn't going haywire -- I get that problem a lot.

Comparing to, the first one is using a chip that already has the Arduino bootloader installed. You want to be using the second example and can stick with that when burning the fuses, writing the bootloader, or uploading the sketch. Uploading sketches via a serial connection is a feature of the bootloader, but when you're building your own breadboard versions you won't be using it unless you specifically want to upload via serial.

In my installation, the two header files are in the same directory in (arduino home)/hardware/arduino/cores/arduino. I'm not sure how or why your hardware/ directory is located under your sketchbook/ directory.
1266  Using Arduino / General Electronics / Re: Chinese PCB Fabs on: March 17, 2013, 11:34:28 pm
Nothing ambiguous about these instructions (both Seeed and Itead use the same image, incidentally). I would guess that the cases where a groove made it through was simply because the boards weren't checked before they were sent off. Or, from the perspective of the employees working on the project, it's probably easier to just let it slide rather than do all the paperwork to reject it.

1267  Community / Bar Sport / Re: Your latest purchase on: March 17, 2013, 03:39:04 pm
I think they have production lines using and warehouses full of older parts they're selling off cheap just to hit certain marks on production economies.

I think they just get the parts at a lower price straight from the distributors. Here in the US it's not uncommon to see things like prescription drugs priced much higher domestically then they are sold overseas. Why would electronic parts -- where competition is much, much higher in China -- not see a similar price decline. The manufacturers have to price them to match the market.

You look at all those cheap LM2596 modules on eBay and there's no way to build one yourself that cheaply; you just can't get the LM2596 at a lower price than the entire module. Now if TI started pricing the LM2596 in China the same as they do in the US I can guarantee those boards wouldn't be built with TI LM2596's; any number of fabs would quickly duplicate the chip.

Yeah it's possible that there's a warehouse out there with a few million overstock LM2596s, but the chip is pretty ubiquitous and still in full production. I can't imagine anyone needing to liquidate it.
1268  Using Arduino / General Electronics / Re: Chinese PCB Fabs on: March 17, 2013, 01:10:56 pm
Hmm, I thought Seeed and Itead had changed their policy on panelizing? Correct me if I'm wrong.

In the instructable he doesn't have any cuts/grooves/holes between his boards -- just a silkscreen line. That's always been allowed as far as I know.

The last time I used Itead I had four boards, each 100mm x 25mm, panelised into one 100mm x 100mm board. They came back with grooves cut in them so I could separate them simply by snapping. I'm still awaiting my first order from Elecrow but I get the impression that they do so too.

I've read of one other person doing that too. Both Seeed and Itead clearly state it's not allowed but apparently it's still possible to slip an order in. YMMV I guess.
1269  Using Arduino / Motors, Mechanics, and Power / Re: Cogs, bands, motors and servos on: March 17, 2013, 01:25:16 am has a complete selection of belts/pulleys but their prices are higher (their market is professional/industrial).
1270  Using Arduino / General Electronics / Re: Chinese PCB Fabs on: March 17, 2013, 01:22:04 am
The Itead/Seeed service won't panelize. You can have the board routed to any shape you want -- and use internal routes -- but the moment you start perforating or cutting the board in any way that will enable you to break the boards apart for separate projects they'll reject it. You can have separate projects on one board, but they require you to do all the separating cuts yourself. Seems confusing, but basically they just don't want you cheating their already quite inexpensive service.

I know OSH Park does panelization but I've never used their service myself.
1271  Using Arduino / Project Guidance / Re: Fast acting gate for laser? on: March 16, 2013, 04:04:51 am
20ms is only 50Hz. Any mosfet can switch much much more quickly than that. Your problem lies elsewhere, probably in the circuitry for the laser module?
1272  Community / Bar Sport / clever site administration page. on: March 14, 2013, 11:25:08 pm
Gotta love it when a web site's "down" or 404 page shows a little humor.

1273  Using Arduino / Project Guidance / Re: construction Laser level for digger on: March 13, 2013, 04:11:00 pm
I have not used the "learning" type of receivers, only the "fixed gain" type. But, from the datasheet, yes it does look like it doesn't require any pauses in the signal. And to answer your other question about those pauses, yes they are there to eliminate interference; fluorescent lights appear to be a big cause of this interference due to their innate flickering.

You can use a receiver that requires pauses but it just makes the programming -- both in making the laser blink and in detecting the beam -- a little trickier.
1274  Using Arduino / Motors, Mechanics, and Power / Re: Old six wire stepper motor... Seagate -- Not sure what I have on: March 13, 2013, 10:34:51 am
Sounds like you have a five phase unipolar stepper. Would work just like a typical, four phase unipolar motor but with one extra phase to deal with.

Your PDF is missing btw.
1275  Using Arduino / General Electronics / Re: Power Supply VS 50 Watt Chinese LED. on: March 13, 2013, 02:52:09 am
The higher the frequency (shorter the wavelength) of the light emitted by an LED, the higher the voltage required.

Y'know I never noticed that correlation before you mentioned it.  smiley-eek
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