Cheap PIC based ADSR

[Tanstaafl]

I mentioned this on the chat room the other day, but interest was low...... this is a GREAT ADSR!

check it out... parts only cost about 3 bux (USD)... well the pots are not cheap but the circuit board only uses about 10 resistors, 3 or 4 caps, a 16f684 pic (14 pin) and an op amp.

I have built 3 of these so far and am very happy with the performance.

here's the link: http://www.tomwiltshire.co.uk/sdiy/envgen.html

he's also got a really nice LFO based on the same circuit.

happy midiboxing!

gb

[DragonMaster]

No sound samples... :'(

[Tanstaafl]

okay, dagnabbit

  I 'll hook it up to something and get some sound files... gimme a day or so.

gb

[bill]

wow, this is VERY interesting  :o

[nILS]

I must not have been in the chat then =)

[Sasha]

That is great. Maybe not for all analog lovers but doesn`t matter.

;D It was very funny to read the news from the creator`s website...

My brother has taken the plunge and got some pigs, so we've got some livestock on the farm again. The pigs are great, curious and fun. They are so obviously happy snuffling in the earth and running around in their enclosure. Much more interesting than boring old fluffy sheep, like we used to have...

[Tanstaafl]

Not really sure what it is HE does for a living, I emailed him to thank him for his design, asked a couple of questions about updates.... here follows the correspondence... hope he does not mind:

Gene,

Thanks for the email, and I'm glad you like the VCADSR. I'm sure you'll like the VCLFO too. It was my favourite out of the two, mainly because of the lovely rhythmic effects you can get by setting the S&H and LFO rates so they are close but not the same. Beating between the two produces a modulation that fades in and out at the difference frequency - it's great!

I have been working on more projects, but nothing as simple or neat as the first two. I've started using dsPIC 16-bit chips, since I felt I needed the power for a good quality digital oscillator, and since doing some experiments with that, I've also started working on a digital modulation matrix, rather like the Oberheim Matrix synths. When these will see the light of day is anyone's guess, but I'll put something up when they're done!

Good luck with your projects.

Regards,

Tom

On 13 Dec 2007, at 21:34, Gene Beth wrote:

Howdy Tom !

Just wanted to drop you a line and a THANK YOU for your VCADSR design.  I have been looking for (and building envelope generators) for years and yours is the BEST!!!

I need an LFO also and yours looks like a candidate for fabrication.

If there are ever any updates, please keep me informed!!

Gene Beth

Houston, TX. USA

[Tanstaafl]

OK,  i've captured a bit of video sorry about the sound quality and my coughing... sick as a dog here....

dang it... my webserver is befrugte..... updates later today

gb

[Echopraxia]

Sorry for the silly question but can these two units have a regular audio source/midi synth sent into them to be modfied then outputed to a mixer? I havent gotten into analog cv stuff at the moment.

[seppoman]

Sorry for the silly question but can these two units have a regular audio source/midi synth sent into them to be modfied then outputed to a mixer? I havent gotten into analog cv stuff at the moment.

these are both sources for control voltages. To have an effect on audio, you e.g. need to apply the adsr cv output to a VCA (voltage controlled amplifier), then you get a volume envelope :)

I like the idea of digitally generated ADSRs and LFOs - as long as the output is accurate, this is actually better than analog CV sources. You get much more possibilities to configure/influence CVs in the digital domain. The actual "analogue sound" comes from the VCO/VCA/VCFs, not so much from the CV sources.

S

[nILS]

Some rather random testing results:

* Board size would be about 1.5x1.3 inches. That's pretty damn small.

* Costs of components: about 4 Euros. That's pretty cheap.

Does this thing actually work (well)? ;-)

[Tanstaafl]

it does

still trying to get my wav/mov file on the  web to show it

dag nabbit

[DragonMaster]

http://www.google.com/support/youtube/bin/answer.py?answer=55744&topic=10526

[Sasha]

Some rather random testing results:

* Board size would be about 1.5x1.3 inches. That's pretty damn small.

* Costs of components: about 4 Euros. That's pretty cheap.

Does this thing actually work (well)? ;-)

PCB already. Great! :) Thank you Nils. It would be nice to publish the brd and send the copy to the creator so he can include it to the other files.

[nILS]

@Sasha, I'd be happy to publish the .brd file, BUT: the one I posted was just a test. I didn't verify the board or the schem yet, which I would really like to do before anyone tries to build it like that ;-)

[Sasha]

Sure. Tanks  ;)

[nILS]

Second opinions and a cross-check with the original schem would be appreciated ;-)

Parts list (pin headers and board not included):

X1			20 Mhz
C1			10 nF
C2			47 nF
C3			15 nF
C4			2n2
C5			22 pF
C6			22 pF
C7			100 nF
R1			15 kOhm
R2			15 kOhm
R3			15 kOhm
R4			15 kOhm
R5			150 Ohm
OPAMP			TL 072
[/code]

[Tanstaafl]

Yep looks good, but nothing like my perfboard layout.....

just about ready to fire my ISP.... and thanks for the youtube link, but no thanks.

still trying to get the vid to MY website.... grrrrrrr

gb

[nILS]

Yep looks good, but nothing like my perfboard layout.....

[ x ] Are there any pictures?

[  ] Is it working?

[  ] How'd you do that?

[Tanstaafl]

yeah,  I might try the youtube thing just to get pics to youz guyz

[Tanstaafl]

ok, it's on it's way to youtube..... give a search for adsr.mov... and sorry for those stuck in the PC world.. but MAC ROX!  ... come on bang the stones together.....

[Tanstaafl]

alright.... i think I got this done correctly... go look at:

http://www.youtube.com/gbethTX

i hope this woix

[DrBunsen]

Oh noes!!  The page has disappeared.

Here's the archive copy

[bugfight]

or you could go here:

http://www.electricdruid.net/index.php?page=projects.envgen7

[DrBunsen]

Thanks.  He's got a bunch of other interesting stuff there I see.