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76  Using Arduino / Project Guidance / Re: Arduino Due vs Galileo vs. TRE for FFT on Ultrasound on: November 09, 2013, 11:02:54 am
Sounds like a great project for an FPGA, due to its parallel nature.
77  Community / Gigs and Collaborations / Re: programmer/engineer needed on: November 09, 2013, 11:00:36 am
I've sent you a PM about this project.

Same here.
78  Using Arduino / Project Guidance / Re: Cannot find Affordable Precise Milligram Load Cell !! Help!! on: October 05, 2013, 10:38:19 am
Most digital balances with milligram resolution use magnetic restoring force as a sensor instead of strain gages.  I believe this is due to the drift in instrumentation amps.
79  Community / Products and Services / Re: Nokia5110 footprint compatible NEW 128x64 LCD on: September 24, 2013, 04:29:29 pm
Do you ship these to the US?
80  Topics / Science and Measurement / Re: Using an Arduino to process white noise into Random Numbers on: August 20, 2013, 10:20:46 pm
If it is good idea to process white noise to get random numbers it would be widely referenced in statistics literature so maybe you want to start there.  Once you find a algorithm from the statistical experts and scholars you could ask here how to implement them.
81  Using Arduino / Project Guidance / Re: IR Receiver Underwater? on: July 25, 2013, 08:23:29 am
IR gets absorbed by water very rapidly probably within 1,000 wavelengths or so so your comms range would be extremely limited.
82  Using Arduino / Project Guidance / Re: Data logging with Xbee on: July 11, 2013, 08:20:15 am
I have never bought a shield I usually breadboard up what I want to verify it works design a PCB send the files to Osh Park and populate the PCB when I get it back.  Shields work well if you want to stay within the Arduino form factor, at times I find I can greatly reduce the size if I break away from the shields.
83  Using Arduino / Project Guidance / Re: Data logging with Xbee on: July 10, 2013, 07:56:47 pm
You need a MCU on each end and an Xbee to do that, Arduinos can be used easily for this but on the remote unit you are going to need to watch for low power usage and maybe an energy source like solar, depending on how long you want to operate.  The XBee unit on the remote unit would look for a wake up from the unit in your hand and then do a data dump.  You could probably only turn the remote Xbee on say every 30 seconds to listen for the wakeup call.  The usnit in your hand would just have to broadcast its wakeup signal for 30 seconds every time it wants a data dump from the remote XBee.

A few details are probably left out but I think the overall framework would work.
84  Using Arduino / Sensors / Re: Wind speed and direction idea on: July 08, 2013, 09:49:04 am
To get an idea of what the working pressure take your pressure sensors and mount them on the roof of the car on a mast (say 12 inches) and drive it on a calm day and see what how the readings correlate to the speedometer readings.
85  Using Arduino / Sensors / Re: Sensor for stringed instruments on: July 04, 2013, 11:20:29 am
I would use a microphone because unlike a piezo element the mic has a much flatter response as the frequency is varied.  The signal would need to be amplified and then I would run the amplified signal into a comparator the output of the comparator could be fed into a digital input on an Arduino.  The Arduino could measure the time between signals coming and get the frequency and then use a look up table to determine which string got plucked.

This is not as hard as it sounds.  One issue that you will have to watch out for is harmonics of the fundamental freq of the string, the string will not give a pure tone but there will be signals at multiples of the fundamental freq. present.  By setting the threshold correctly on the comparator you will be able to filter out the harmonics.

86  Using Arduino / Project Guidance / Re: Need to shrink and package Arduino Project on: June 30, 2013, 10:29:36 am
To get airspeed you need the difference in pressure between the atmospheric pressure and the dynamic pressure caused by the motion of air into the Pitot tube.  Some applications use one probe with a tube pointing parallel to the center line of the fuselage and one port perpendicular to the first.  The first port gets the dynamic pressure and the second gets the static pressure (atmospheric).  These ports are connected to the 2 ports of your differential pressure sensor to get the differential pressure. 

Hope this helps.
87  Topics / Science and Measurement / Robust Data Logging on: June 23, 2013, 03:36:38 pm
I am logging data onto a PC using serial I/O with the USB cable.  Robust means that when the power cycles the PC will automatically continue to log the data without user intervention.

Does anyone know of a Windows 7 application that would do this?

88  Using Arduino / General Electronics / Re: Chinese Component House Starting w/ Tama??? on: April 22, 2013, 11:48:31 am
That is the one.

89  Using Arduino / General Electronics / Chinese Component House Starting w/ Tama??? on: April 22, 2013, 10:30:23 am
A while back someone on this forum pointed me to a component supply house whose name I belive started with Tam.  Does anyone know the source I am referring to.

90  Community / Products and Services / Re: Square Inch PCB from Electronic Interconnect. on: April 16, 2013, 05:43:55 pm
$3 per square inch is that for 1 or a 100 boards??

I agree that having to create an account to see the prices or post a message here about how good are prices are without a decent disclosure as to what their prices are.  You have heard from any number of people that are not happy to create an account to see your prices.  Claiming to have over 3000 happy customers in response to customers that are not happy with your hidden pricing information is not being very customer friendly.

I do not understand hiding your prices on an instant quote system as any of the competitors could easily use a throw away email account and get your prices easily. 

I am always suspicious at comapanies that are not proud enough of their pricing to advertise up front and out loud, it sounds like I am not the only one.  In today's information age we have all been conditioned to instant gratification in terms of pricing and I think the vendors who realize this will prosper on the bones of those who don't.

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