Show Posts
Pages: [1] 2 3 ... 56
1  Using Arduino / Motors, Mechanics, and Power / Re: Issues with continuous rotation servos on: August 04, 2013, 08:29:35 am
The servos should be perfectly happy with 6v instead of 5, meaning 4 AA batteries can be a convenient external power supply.

The issue you were having was the arduino browning out; the motors drew too much current, starving the chip, and causing it to reset.
2  Community / Bar Sport / shameless plug - my new song on: March 29, 2013, 10:57:39 am
So I haven't posted here in a while, mostly because I haven't done all that much new with the arduino recently.  I've been doing lots of other stuff, like making electronic music.
Just to somehow connect this to arduino, one device in my completely hardware-based setup (no DAWs!) is an arduino-based wavetable synthesizer that has been an ongoing project for me.  The arduino, run thru effects in some places, did quite a few of the synth sounds in the song.  (not the bass, though, that's my analog minibrute synth)

Anyway, here's my new song:

also on soundcloud
also on bandcamp
3  Community / Bar Sport / Re: Your latest purchase on: December 26, 2012, 09:17:38 pm
Half-purchase, half-gift, an Arturia minibrute analog synth.

I love it.

I've already posted 4 demos of it to soundcloud.  And I haven't even tried hooking it up to my other gear yet, I've only so far messed around with its internal features and simple multitrack recordings in Garageband.

here's a partial cover I did of a song I like, all sounds including drums synthesized by the minibrute:
4  Community / Bar Sport / Re: Christmas List on: December 08, 2012, 09:48:53 am
Monotron is lots of fun.

I'm asking for a legit analog synth, the arturia minibrute (well, not asking, more like telling my parents that I want it and paying for most of it myself)
5  Community / Exhibition / Gallery / Multi-timbral MIDI Synth on: October 17, 2012, 09:26:34 pm
Alright, this has been a very long-term project.  This is the third hardware design I've gone through in a few years, and one that I'm really happy with.  I think this may well be one of the most advanced synths ever made with arduino.

I'll post more specific info later, but for now here's a video and a few pictures:

Every sound in that video was made real-time in one take simultaneously by a single arduino, sequenced via MIDI by my mpc.  The only external effects I used were a little bit of EQ, and some sidechain compression, with the noise channel on the synth routed from the second DAC output to the sidechain of the compressor.

Here's a random picture of it before I programmed it:

random test by beefinator, on Flickr

Here's the insides:

better synth guts by beefinator, on Flickr

I'm especially proud of the hand-wired dual-color LED Matrix display (fully functional):

ugh... by beefinator, on Flickr

More info (and more progress) to come!
6  Using Arduino / Displays / this'll be fun... on: August 05, 2012, 12:56:45 pm
So I'm making a new LED matrix board for the newest version of a synth/sequencer I've been working on for a while.

I designed one a couple years ago in Eagle that I got fabbed by batchPCB.  It was okay, there were some silly design errors and general newbie layout and design (all auto-routed).

I re-made the schematic, making sure there were no errors, and making some little improvements here and there, and just for the heck of it, I decided I'll hand-wire it this time...

Here's the schematic.  The 5 shift registers that control the display are all daisy-chained, so only 3 wires (data, clock, latch) are needed to control the entire display.

a schematic by beefinator, on Flickr

And here's the board I designed.  Yes, I used Eagle again, but this time it was all manually laid out and routed.
I designed it so that I could wire up everything on the back of the board with uninsulated solid wire; the red traces in the design would be higher above the board than the blue traces, or vice versa.

circuit layout by beefinator, on Flickr

The 6-pin header (ICSP pinout, just an arbitrary choice to have a uniform system to connect the individual boards within the synth's enclosure) and the caps are not laid out and connected yet, but that's trivial.  E.g. the 0.1uf caps cam probably just be soldered wherever they fit on the back of the board across the Vcc and Gnd pins of the 595's.

I imagine this board will look pretty cool when it's done...

[sarcasm]But this is certainly going to be fun wiring it all up...[/sarcasm]
7  Using Arduino / Programming Questions / Re: MIDI synth - noise on serial reception? on: June 18, 2012, 06:25:52 am
Alright, so I fixed the problem!  There's ZERO audible noise of any sort now, even when I turn up the gain on my mizer to far past comfortable levels!

The solution I found on ladyada's page for the waveshield:

Turns out (and it makes sense) that you need a very low lowpass filter inputting the Vref pins on the DAC.  I had it originally connected directly to 5v, which was a very noisy power line.  E.g. the optoisolator was drawing current when MIDI messages were received, so the voltage fluctuated.
The waveshield uses a 15Hz cutoff filter; I got much better results with a 0.033Hz filter.   smiley-eek   It might take a second or two to ramp up to full voltage on startup of the synth, but I don't care, I have a little splash-screen anyway that appears.
8  Using Arduino / Audio / Re: "Click"-noise on note start on: June 18, 2012, 06:19:29 am
I'd recommend the MCP4921/4922 (1 or 2 channels).

There's an SPI interface on it, so super easy to interface.  12bit audio on each channel, 2 channels if you get the 4922 chip.

And they're extremely low noise.  You just have to (as I just found out) put a very low lowpass filter on the Vref pins, not directly connect them to 5v.  I mean really low; I'm using one with a cutoff of around 0.03Hz. 
9  Community / Bar Sport / Re: What projects do you currently have in the idea phase? on: June 06, 2012, 09:03:16 am

A simple board for use with typical LCD displays (like the 1602 standard, etc) that convert them to either SPI or UART so they don't take so darn many pins.  I want something I can slap between Arduino and those LCD's and just make it simpler.  I think we all would like one of these from time to time...probably going to require a few library changes or making a fresh one from scratch..

it's been done...
They've also got a kit one that's atmega328-based, so it's arduino-compatible.
10  Using Arduino / Programming Questions / Re: MIDI synth - noise on serial reception? on: June 05, 2012, 10:20:40 pm
So the noise has nothing to do with the DAC chip.  I put 2 10k resistors in a divider arrangement, giving 2.5v, the same as the output of the DAC when no notes are playing.  Then connected the output jack to the divider, bypassing the DAC, and I still get the noise with MIDI message reception.

I'm stuck...     smiley-confuse

Tomorrow I'll try making my own MIDI input circuit on a breadboard, to see if the sparkfun board's an issue.
11  Community / Bar Sport / Re: What projects do you currently have in the idea phase? on: June 05, 2012, 01:54:08 pm
The RaveTie - a white tie containing a row of 16 addressable RGB leds, like these:
12  Community / Bar Sport / Re: SimpleCortex - anyone experience? on: June 05, 2012, 01:49:53 pm
Seems ridiculous to compare this to the 328-based arduino.  It's only ~$5 cheaper than the 2560-based ones, or the Ethernet one.
And the specs don't seem stacked up like they advertise when compared to the Mega.

Arduino's also got the community that goes with it, and at least from the glances I took at the simplecortex, more documentation.
13  Community / Bar Sport / Re: The Audio Post on: June 05, 2012, 09:30:02 am
thanks.  I plan on making an even better enclosure for a new version of the synth when it's done.

And it's just "beefinator", the 2 is just because it's my second account, because I ran out of minutes on my first one.
14  Using Arduino / Programming Questions / Re: MIDI synth - noise on serial reception? on: June 05, 2012, 09:28:02 am
I've already uploaded samples, the noise is only an issue when using pitchbend or control messages, or low velocity notes.  On notes with higher velocity, the click isn't noticeable.

Check out my soundcloud, link in my signature, for some samples, and also some songs I've made with the previous version of the synth.
15  Using Arduino / Programming Questions / Re: MIDI synth - noise on serial reception? on: June 04, 2012, 11:34:57 am
So here's the circuit:

One thing I tried:  I replaced the 220Ω resistor labeled R2 in the sparkfun schematic with a 1KΩ resistor.

That value seems to be the correct value according to the optoisolator datasheet, not the MIDI hardware spec.  The noise is quieter with the larger resistor, but still audible.  I also tried a 10K, but not much of a noticeable difference from the 1K.

And jman, here's a good midi monitor if you don't already have one:
Pages: [1] 2 3 ... 56