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211  Using Arduino / General Electronics / Re: Agilent has oscilloscopes to 63 GHz /160GS/s. How is that possible? on: February 06, 2013, 04:24:11 pm
I had an 8 GHz scope a while back, and it is done with 8 bit flash convertors and you use multiple ones and interleave the data. I am sure they have a white paper. For example, if you have 16 convertors, they each need to sample at 10 GS/sec.

Out of curiosity I have looked at TI/National, Analog, and LT's sites and I think the fastest converter that is available is TI at about 5 Gsps and that is at 7-bit.  The datasheet shows it's actually 4 ADCs embedded in one chip with some clock management.  So maybe you use 32 of those?  But how the heck do you interleave them so that they are sampling at the correct point in time?

HP/Agilent were never afraid to design their own hybrid chips so there is no telling how they are doing it. They used to publish a nice Journal that had articles on their technology but I can't find that Agilent do that.
212  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 04:08:28 pm
What if instead of a dip switch I have a tiny push button and LED.  The user could push and hold the button till the LED blinked once, or twice, or three times etc. and then release and that would be the selected setting.  I would read their inputs on the button and write something to eeprom and store their selection.  That might be even more slick and would only require drilling some holes for a button and LED which can be made to look very clean and factory.

Probably an interface hotrodders could identify with. Be sure you consider a way to bail out and cancel any changes.
213  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 03:53:25 pm
Something else I thought of.  Maybe I can find a round dial type dip switch.  One that you put a tiny screw driver in and turn.  Then I'd only need to drill a round hole for the end user.  That would have the potential of looking much less ghetto lol smiley

Maybe if you tell us what the end user needs to set with the dip switches, someone can suggest a way to do it in software. Even less ghetto. smiley

Well the module I created is for automotive purposes for controlling nitrous on a car based on various conditions.  So what the end user receives is a box with some wires that they tap into their cars ECU, TPS (throttle position sensor) etc.  then if they'd like to fine tune a few things like perhaps their nitrous is kicking on a little to early in the RPM range they could adjust the dip switches to change behavior of the box.  I'm not sure how they'd do that in software?  The target customer base has no idea what an Arduino is or the IDE software used to code it up.  If there was some sort of end user software I could distribute to a user that popped up a simple window where they could adjust some settings and save that would be slick but I'm not sure how do that.

If you provide a USB serial interface on your product, it would be simple to add a configuration screen that used the terminal program on the end user's PC. On the other hand, that may be too sophisticated for your intended audience. Probably a better idea to go back and select an enclosure and then make your circuit board fit it.
214  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 03:26:58 pm
Something else I thought of.  Maybe I can find a round dial type dip switch.  One that you put a tiny screw driver in and turn.  Then I'd only need to drill a round hole for the end user.  That would have the potential of looking much less ghetto lol smiley

Maybe if you tell us what the end user needs to set with the dip switches, someone can suggest a way to do it in software. Even less ghetto. smiley
215  Using Arduino / Audio / Re: Mems microphone lavalier style ( tie/shirt clip microphones ) on: February 06, 2013, 01:20:58 pm
I've got a little project using the Mems microphone here on Sparkfun ADMP401, i 'm asking about feasability. it's a diy Lavalie microphone ( the ones you clip to tie, or shirts for Interview )
I need the microphone to output to a mcu which will then send via RF ( 2.4 ghz) to a receiver which ll do the DAC conversion to an xlr output.

Is it easy ? i know the transmitter mcu should do some "processing" and the receiver some amplifier, what are my best options ?

Regards
J.
So, basically, you're talking about a digital wireless mic? No, not easy if you expect it to be reliable and not especially inexpensive either. You need to fill in some blanks here before you will get any advice other than speculation.
For starters:
  • What bandwidth do you require?
  • What range do you require?
216  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 12:48:37 pm
Quote
I found a rough price guide on polycase's website and unless you order units of 10+ it's really pricey.  Hard to start out and get a few units made to finish out prototyping like that.  It'd be so much nicer if any standard square enclosure had a small slot on the side for dip switches.

There are at least two hackerspaces in the Kansas City area. If you are not a member and are not using them you are wasting a valuable resource.
217  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 12:21:20 pm
One way is to select an enclosure and the have the manufacturer laser cut a slot where you need it.Call Polycase and ask them what they would charge.


I did notice some websites offered that service but no pricing is displayed online.  I was hoping to find something out there easily and readily available.  It would also keep costs down.

If I did decide to go with the custom case route, have them cut it then I might as well go all the way and have my company logo printed/painted on too.  Which company do you guys recommend for that?  Searching google returns so many thousands of results it's quite overwhelming sifting through all of it.

I'm only familiar with Polycase. If your local hackerspace has a laser, you can tweek your design before you send it out for production. Depending on volume, you might be able to produce enough cases yourself.
218  Using Arduino / Project Guidance / Re: Looking for enclosure with a slot for dip switches? on: February 06, 2013, 12:07:44 pm
One way is to select an enclosure and the have the manufacturer laser cut a slot where you need it.Call Polycase and ask them what they would charge.

 Edit:
Finalizing a product with no consideration of how it is to be packaged is a rookie move that hopefully OP recognizes. There is no simple and/or inexpensive solution for that mistake.
219  Using Arduino / Project Guidance / Re: Taking a shot at specific gravity measurements on: February 06, 2013, 11:55:29 am
Quote
Hang on Lefty, are you just saying that SG can be determined simply by having two pressure sensors take a differential reading from fixed points? Because that would be much more simple (though far less sexy) than my idea. I could even attach the sensors to rod or something, the way I could move them from one bin to another providing I used the same type.

To give you a feel for how that could work in a home brewing setup, let's say your two pressure taps are about 30 inches apart. The differential pressure would be about 1 psi. If your SG changed by 0.05, you would see a differential pressure change of about 0.05 psi. Could work nicely with the proper differential pressure transducer.
220  Community / Bar Sport / Re: Look what I found... on: February 06, 2013, 11:14:42 am
That spaghetti board reminds me of grad school. We had an IBM 1620 that was kind of like our own PC that we could do whatever we pleased with. The IBM reader-punches were programmed with a plug-in card very much like that spaghetti board. If you changed that board, you could punch and read cards that had a completely different coding from normal. I carefully keyed in a very long program before I noticed that the last user had not removed their custom programming board. Doh!
221  Community / Bar Sport / Re: KIckstarter of the week - USB micro led cable! on: February 06, 2013, 11:06:45 am
This is merely a usb cable with 30cents led and probably a 300ohm resistor, not exactly a new concept, besides i have issues finding the usb cable in the dark to begin with...
They could make the housing out of glow-in-the-dark plastic.  smiley
222  Using Arduino / General Electronics / Re: Parts Database - PartKeepr on: February 05, 2013, 11:36:04 am
A spreadsheet works just fine for me. I keep it in the cloud so when I'm away from the house and I need to know if I have any of some nifty item I just saw at a swap meet, I can look it up.
223  Community / Bar Sport / Re: KIckstarter of the week - USB micro led cable! on: February 05, 2013, 09:33:40 am
Presumably the design of the lightning connector was driven by the above observations, ie as connectors get smaller it becomes more and more convenient for users to eliminate orientation issues. Obvious visual cues (such as the oblong shape of a IEC power connector) are not as obvious when things get tiny.

The lightning connector can be correctly mated in the light or dark, eyes wide open or shut, drunk or sober  smiley, and it seats with such a satisfying "chunk". It gets my vote for the perfect miniature charger connector. No LED necessary.
224  Using Arduino / General Electronics / Re: How do you calculate what the voltage will be after a resistor? on: February 04, 2013, 09:27:03 pm
Yep, Ohm's law is not gong to change because it is a definition and by definition, true.  smiley

Except near the speed of light, eh?

I'm waiting for "Ohm's Law of Relativity".
smiley-lol
225  Using Arduino / General Electronics / Re: How do you calculate what the voltage will be after a resistor? on: February 04, 2013, 09:15:01 pm
We had the Fluke version of the differential voltmeter in my lab at TI in the 60s. I don't think they have changed much in theory since then.

No, most theories change very slowly and rarely if at all over time. Ohm's law is still hanging in there.  smiley-wink

Yep, Ohm's law is not gong to change because it is a definition and by definition, true.  smiley
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