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1  Using Arduino / Project Guidance / Re: Arduino Due vs Galileo vs. TRE for FFT on Ultrasound on: November 09, 2013, 01:34:11 pm
thanks, that is a very good one.
2  Using Arduino / Project Guidance / Re: Arduino Due vs Galileo vs. TRE for FFT on Ultrasound on: November 09, 2013, 12:27:53 pm
One problem with your idea is that there aren't any microphones that will respond from 1 Hz to 60 kHz. Good microphones that respond reasonably uniformly (+/- 3 dB) from 20Hz to 20 kHz are remarkably expensive.

Above 20 kHz you need ultrasonic transducers, which usually have quite narrow ranges of response. An exception is the Polaroid ultrasonic transducer, which has a +/- 10 dB response from about 20 kHz - 100 kHz.

Good you told me that. In a sense I might get away with narrower band. I just thought to start with 1kHz as less demanding and than move up.

I was more after some explanation weather this huge processing power of Gallileo and TRE are available for Arduino code? The way I understand it by reading online specs, Arduino IDE and Arduino code can't really use this power. It is pretty much spent inside Linux and Arduino side has no benefit. Is that right?
3  Using Arduino / Project Guidance / Arduino Due vs Galileo vs. TRE for FFT on Ultrasound on: November 08, 2013, 05:40:07 pm
I want to read 7 microphones as fast as possible, and do FFT on them. Than manipulate received audio and play it back to 7 speakers. All that from low audio like 1kHz to reasonably high ultrasound 50-60kHz.

OK, granted it might be a pipe dream, but which one of new Arduinos can do it: Due (80MHz), Galileo (400MHz) or TRE (1GHz) is most likely to be able to accomplish this.

I am bit confused at how Galileo and TRE work. They seem to be running "virtual" Arduino.inside Linux software. Is that good interpretation?

Can one move data fast enough between hardware and "virtual" Arduino to achieve real time syntheses audio playback.

Can one use that awesome processing speed from the Galileo or TRE to do heavy calculations and than return them to Arduino part? Or is that processing speed wasted on screen, keyboard and mouse etc.?
4  Using Arduino / General Electronics / Re: Purpose of the Power Supply Ground terminal? on: October 02, 2013, 12:00:09 am
What does it mean that "voltage is floating"? And is that good or bad?
5  Using Arduino / General Electronics / Re: Purpose of the Power Supply Ground terminal? on: October 01, 2013, 04:46:36 pm
Thanks, at least I know. What is normal? Should "-" terminal have a negative voltage in reference to Ground terminal?
6  Using Arduino / General Electronics / Re: Purpose of the Power Supply Ground terminal? on: October 01, 2013, 04:07:05 pm
OK, so my Ground is just "fake" and it is there for good looks. Is this normal with other power supplys, or should I get a new one?
7  Using Arduino / General Electronics / Purpose of the Power Supply Ground terminal? on: October 01, 2013, 03:42:07 pm
I have a power supply with 3 terminals: "-", Ground and "+".

Now I know that Ground is mains ground, but what does it mean? I thought that negative "-" terminal and Ground should be very near to each other. So I took voltmeter out and to my suprise the difference between the "-" terminal and Ground was zero, but the difference between "+" terminal and Ground was zero as well. I mean power supply was ON and output was ON, but the difference between both terminals and Ground was zero. How's that possible when "+" and "-" was as set on the voltage dial?

Deeply misterious  smiley-fat
8  Using Arduino / General Electronics / Re: Transistor Graphing Device on: October 01, 2013, 03:02:59 pm
Yeah, nice and simple circuit, but I do not have power supply with -10V.

Additionally, even if I had supply with -10V, can I damage oscilloscope? Where is my ground?
9  Using Arduino / General Electronics / Re: Transistor Graphing Device on: October 01, 2013, 02:46:20 pm
thanks, you are right, it was "top left".
10  Using Arduino / General Electronics / Re: Transistor Graphing Device on: October 01, 2013, 01:48:26 pm
Here's a circuit than sources current (a bit harder than a programmable sink)
http://www.seekic.com/circuit_diagram/Power_Supply_Circuit/VOLTAGE_PROGRAMMABLE_CURRENT_SOURCE.html

I don't understand strange symbol in top right of the picture. It shows +-10V Gnd, but there are no +/-10V rails in the rest of the circuit. Does this circuit require positive and negative voltage power supply?
11  Using Arduino / General Electronics / Re: Transistor Graphing Device on: October 01, 2013, 12:04:39 am
Hi, I uploaded a new image with clear values.

Yeah, learning the analogue side was like jumping on hyper-drive. My ability to create new applications jumped into hyperspace. It is much more scalable than digital and although you can 'fake' things digitally, they'll always flimsy, depending just on a single byte before they crash. With analogue you have a feature built into the core of the system and than you just polish it with digital. Not the other way around.

Only problem with analogue is that one can forget about doing it intuitively. One really needs to learn maths behind it.
12  Using Arduino / General Electronics / Re: Transistor Graphing Device on: September 30, 2013, 04:26:41 pm
Why are there values expressed as fractions?

I think you are chasing a unicorn, trying to get symmetrical clipping in a single transistor Class A amplfier.

Sorry about fractions. I removed them. That was just error. Please have a look again.

Are you saying that single transistor Class A amplifier will always clip on one side? That means essentially my design work "normaly" for what it is.

Strange thing is that I had these same values on a breadboard and it worked without clipping. Only when I transfered the design onto perfboard it started clipping.
13  Using Arduino / General Electronics / Re: Transistor Graphing Device on: September 30, 2013, 03:10:23 pm
Here is the circuit. Pure marvel of technology  smiley-cool



Values on the picture are wrong. Real values are these:

Vcc= 16.5VDC, RIN= 33Ω, CIN= 4.73μF, R2= 8.97kΩ, R1= 1.253kΩ, Rb= 0.00Ω, Rc= 167Ω, Re= 13.4Ω, Clow-f= 47.7μF
14  Using Arduino / General Electronics / Re: Transistor Graphing Device on: September 30, 2013, 12:31:33 pm
I have this one:

http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html

but it is puny little thing, only goes to 10mA. For an ordinary BC548 transistor, that is about 1/10th of its capacity. It has brilliant software, though.
15  Using Arduino / General Electronics / Re: Transistor Graphing Device on: September 30, 2013, 05:23:44 am
;-))) programmable resitor. I am such a rookie. Thanks.

By the way, does anybody know any comercial transistor curve tracer that can work in 10-1,000mA and is bellow $200?
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