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1  Products / Arduino Due / Re: Our Life With The Due on: April 11, 2014, 02:57:11 am
Hhmm.. I thought I did use the pinMode().. Will check again, when I get round to it..
2  Products / Arduino Due / Our Life With The Due on: April 10, 2014, 03:21:46 pm
Just a little blog post dealing with our recent Arduino Due experiences..

Hope you enjoy it. And if there is any expert that can tell me why GPIO pin 53 is always high?
3  Products / Arduino Due / Re: INPUT_PULLUP on: March 15, 2014, 08:52:36 am
reading this i gather that a bigger pull-up resistor might lower the registered voltage and hence it might not be seen as high anymore. it's logical.

..but then it might be nice to consider using external pull-up resistors on the DUE..
4  Products / Arduino Due / INPUT_PULLUP on: March 15, 2014, 08:16:38 am
A project I made (originally for AVR based Arduino) uses INPUT_PULLUP mode on some of the digital pins to read out of tactile switch. On the UNO, this works fine. On the DUE, it's unstable somehow. When the switch is open and my hand comes close to the wire there's a square wave instead of a constant value.

I read that the DUE the pull-up resistors have higher impedance, but how can that cause this?

5  Products / Arduino Due / Re: DUE PWM Frequency on: March 14, 2014, 03:15:26 pm
the AVR has so-called "accurate PWM mode" to facilitate this h-bridge control (pulse is always centered around a unique determined point in the PWM period). it seems the Due's SAM has what Atmel call "complementary" mode. this is only available on the four PWM pins. the other pins are called TC (Timer/Counter) and do not feature complementary mode.

btw. . changing TC_FREQUENCY does not  mess up delay() or micros(). i'm a happy man smiley

6  Products / Arduino Due / Re: DUE PWM Frequency on: March 14, 2014, 01:34:24 pm
in variant.h:
change the line:

#define TC_FREQUENCY        1000


#define TC_FREQUENCY        300000

and as said previously:

#define PWM_FREQUENCY           1000


#define PWM_FREQUENCY           300000

the frequency doesn't have to match exactly. it's governed by the mother clock divided by the pwm resolution (256 steps) divided by a power of two. the max would be 84 MHz / 256 = 328.125 kHz.

hope that clears things up. there could be more elegant ways and i still have to test what this does to micros() and delay().. on AVR-based Arduino that issue exists.
7  Products / Arduino Due / Re: DUE PWM Frequency on: March 14, 2014, 09:48:24 am
to change the PWM frequency of all pins.. that means also the ones not in range 6,7,8,9.. you should change also TC_FREQUENCY in variant.h.

this works perfectly. i get a nice 330 kHz period for all pins now.
8  Community / Products and Services / Re: Analog bass synthesizer shield on: March 13, 2014, 02:10:44 am
Demonstration video, new firmware, etc:
9  Community / Products and Services / Re: Analog bass synthesizer shield on: December 22, 2013, 10:06:31 am
Selling them for 49 (ex VAT) now:

For several demo's using the Piggy:
10  Community / Products and Services / Re: New Product: Audio Hacker shield on: August 24, 2013, 02:42:02 am
cool, excellent, that stackable design!
11  Community / Products and Services / Re: Analog bass synthesizer shield on: August 24, 2013, 02:30:27 am
the prototype's first audio clips:
12  Community / Products and Services / Re: Analog bass synthesizer shield on: July 24, 2013, 03:48:23 pm
I now have a running prototype:


Audio demos to follow smiley-wink
13  Community / Products and Services / Re: Analog bass synthesizer shield on: May 04, 2013, 04:57:14 pm
OK, here's the anti-vaporware photos smiley-wink

early prototype: the VCO, VCA and filter (cut-off only)

close-up of the VCO

strip-board version of the filter and output circuit, including resonance and cut-off potmeters
14  Community / Products and Services / Analog bass synthesizer shield on: April 29, 2013, 12:44:22 pm
Hi guys,

I'm new to this forum, but I've been working with Arduino for half a year now. Have to say it's a great platform... the hacking is good smiley In the last months I've finished a prototype of an analog bass synthesizer. It's on separate circuit boards now, but will be intended as a shield for the Arduino. I aim to release it for ±100 euro fully assembled, and ±70 euro as a kit.

- 20Hz - 6 kHz pitch, controllable in 65536 steps (using Arduino PWM)
- sawtooth and square wave oscillator, with toggle switch
- Low-pass resonant filter with 1 potmeter for resonance, and 1 for cut-off (high quality pots, no trash! smiley)
- 3.5 mm headphone jack
- 8 pushbuttons to select basslines
- switches for portamendo and "echo" effect

Is anybody interested in a purchase? I hope to mass produce the shield by the end of the year. Also, if anybody would like to suggest some features, please let me know.

I have plans to add an additional drummachine onto the shield (the 808 to back-up the 303 smiley-wink), but it might be a little too ambitious...

Thank you for your attention!
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