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181  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 10, 2008, 02:04:05 pm
Worst case cost, for something that plugs in exactly link a blinkM is another cap and a 3.3v regulator, so add about 0.60 cents to the part cost ($1.20 end cost).
182  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 10, 2008, 02:01:33 pm
Some costs (in 100s) for an LIS302DL ushield that plugs into a bigger shield:
LIS302DL: $7.59
1sq in PCB: $0.64
Misc passives: $0.30 (two or three caps )
4 pin header: $0.07
----
$8.60

Even assuming Ladyada's 'double part cost' pricing system, we're looking $17.20US (10.90 Euro).
183  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 10, 2008, 01:33:51 pm
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ok, exactly that, but with a different pinout... and it is priced like the nunchuk... interesting because Sparkfun used to charge like 35 bucks for the other accelerator breakout boards.
These sensors are marginally cheaper, and they admit to mucking up a small detail, but mostly I think these are cheaper because they have to compete with the nunchuck.
184  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 10, 2008, 01:12:20 pm
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The Arduino i2c is 5V, so we need to add an i2c bus adapter, from 5V to anything else down.  I am running some tests using the PC9306.  i2c is a bidirectional bus and a simple voltage divider doesn't work.
. I'll admit, this is a tough issue. Unless I'm mistaken the PCA9306 are SMD only and I haven't managed to find anything bi-directional that isn't SMD.
While there's nothing wrong with surface mount, it adds complexity (or cost) to kit building.
185  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 10, 2008, 12:37:59 pm
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have a voltage regulator (3.3V or better a variable one with 3.3, 2.5, 1.8V)
Would you have one voltage for every port, or selectable at each port? I can see you'd need at least selectable between low-voltage (3.3/2.5/1.smiley-cool and 5 volt. Or dedicated ports for 5v vs low-voltage.
I know alteast maxim, and I beleive Microchip, ON and many more, make multi-output LDO regulators or SMPS with all 3 requested voltages.

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It can have vertical ports and horizontal ports.
I picture ports arranged around the perimeter of the board, allowing you to install either straight or right-angle headers to use them as either horizontal or vertical ports.
186  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 09, 2008, 11:29:15 pm
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Designers here too could upload boards that customers could order.  Here both the New company and the designers would get a cut.
Of course some of the less run designs would have to be set up similar to batchPCB (sparkfun)... However, a deal could be struck with GoldenPhoenix too (as BatchPCB) did for this kind of service.   As designs get more popular, they could be Run ahead of time to save time and money.

I think we're talking about more than just boards though, we're talking full kits. This means, not only would you need just in time (JIT) PCB manufacturing but also a JIT component supply. You'd have to feel the market out, but I imagine most consumers are looking for 'ships today, tomorrow, or the day after', not 'ships in two to three weeks when all the parts and the pcb come in'. This limits a model like this to very quick-turn PCB lines (and overnight/1 day manufacturing of a single board or panel isn't cheap nor the quick shipping) and very fast suppliers (mouser, digikey, portions of newark, etc). Practically you've just pushed all the startup cost onto each end consumer.

I think realistically, the barrier to becoming a designer is having a (small) run of boards made and purchasing enough hardware to make kits for them. Assuming there is a collective though, these costs could be limited by creating panels instead of single designs and bulking up everyones orders for quantity discounts and access to larger distributors.
187  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 09, 2008, 09:22:31 pm
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I can get 100 boards including PCB design for under USD$200.
Not to derail the discussion, but who do you use as a manufacturer, thats cheap!
188  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Larger Arduino projects on: April 09, 2008, 09:17:45 pm
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Interesting... a collaborative e-business.  Implementing regional distribution centers make more sense, the difficult part is finding or writing the software to control all the operations.  The e-commerce software is still very immature, and there is a huge opportunity for someone who wants to do it right... yahoo couldn't do it right, neither amazon.com...

The shipping would be deadly if you order 4 products from the site and they come from 4 different suppliers.  It would have to be all items shipped from the same place.

I'm fairly certain NKC was pushing for the opposite idea entirely. Currently, there are small-time sellers spread out everywhere, what if they all carried each others products, either through one site that farms shipping out to the closest distributor or through individual sites?

I can see a consignment system, but with a marginal upfront fee to cover becoming a member of the collective
189  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Hardware/Circuit question on: April 08, 2008, 09:30:39 am
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There's a secondary idea to also step the voltage down to 7 to 8v.  That would be a switched/photosensor'd situation though to control the brightness at certain times.
This would be an excellent job for PWM and analogWrite. Assuming your FET switches faster than the Arduino's PWM speed, no extra hardware should be necessary. (You may need to lower the 'protection' resistors Severino2020 talked about, depending on your MOSFET's gate capacitance. Try it unmodified, if the MOSFET gets `hot` then it's likely not switching fully and you should lower the capacitance.)
190  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Getting a 5V supply from the board? on: April 08, 2008, 09:26:20 am
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Took me quite a while to figure out why my meter was not showing any current in spite of the fact that 3 ultra bright LED's was shining happily  :-)
Hmm, every multi-meter I've blown the current measurement fuse in (many now have PTCs) has cut current to the circuit too; this is usually my first indication the fuse is blown. Some of the nicer bench meters have LEDs indicating a blown fuse.
191  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: 1mA analog meters on: April 06, 2008, 12:18:56 am
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Just out of curiosity, what type of enclosures are yall thinking of using for your clocks?  I did mine in a black wooden box because it matches our decor.  But the other idea I had was to use a metal enclosure that looks like it should have been mounted in something like a Nasa control panel

I now have a few clocks, but the nicest of the lot has been set into a 4U 19" rackmount blank. It was (and I assume still is) installed below a plethora of other meters in a theatre's dimmer bank. It fit well in a room were every wall was covered by floor to ceiling cabinets and it did much better than the clock mounted on the back of the door.
192  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: 1mA analog meters on: April 04, 2008, 10:32:26 am
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you must subscribe to make!...
you know, i had the idea last summer, even sketching it down, but never moved forward... then, my wife gives me a subscription to make for christmas and damnit if this issue didn't have the same exact thing...

Sadly, I don't get make, it has been featured on their blog a few times now and on boing boing long before that. I've had a panel meter clock kit in the works for a while now, but I've never quite finished it. Panel meter clocks are, therefore, always on my mind.
The all-electronics meters look nice.

I think we've all been bested for the origin of this idea. Theres pictures of a mid 1800s schooner with 2 mechanical dials displaying time in virtually the same fashion. The clocks measured watch time and were powered by hung weights. I wish I remembered where I saw it.
193  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: 1mA analog meters on: April 04, 2008, 09:41:15 am
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i've found a project that requires three of them, but i can't seem to locate any online!
Building a meter clock?
Futurlec carries both voltage and analog meters but none at 1ma. Same story at Jameco You might, however, be able to bodge a high-value (or one of the voltage) meter into service by replacing the bias-resistor? I used this to convert some 100A meters into 10mA meters.
194  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Headers and Interconnects?? on: April 02, 2008, 10:26:29 am
Like so many things, Futurlec carries a whole bunch of pin headers (male, female, etc) for cheaper than anyone else I can find.
Some people hate them, some people like them. I always receive my purchases, but other people apparently have issues.
195  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: selectable baud rate on: April 02, 2008, 10:31:33 am
Ideally you should have some sort of basic state-machine.

Code:
int SerialSpeed;

void setup(){
  SerialSpeed = 0;
  Serial.begin(31250);
}

void loop()  
{
    if (switch is on && (SerialSpeed != 0))
      {
        Serial.begin(31250);
        SerialSpeed = 0;
      }else if(switch is off && (SerialSpeed != 1))
      {
          Serial.begin(57600);
          SerialSpeed = 1;
      }
 
your code...
}

Now you're only re-initializing the UART when you need to change speeds.
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