Wogglebug circuit

6079smith · Posted: Thu Mar 26, 2009 2:45 pm Post subject:

Sorry, I was thinking of another LED thing I did on the Wogglebug I made - a bicolour on the woggle tone output.
Which version are you using? If it's Richard Brewster's version, I can see there's a transistor inverter just before the output buffer for the clock output... maybe you could take the driver input from just before that?

Audent · Joined: Dec 19, 2007 Posts: 24 Location: oh-hi-oh

looks like Wogglebug PCB's are back in stock at bridechamber- exciting!

sduck · Posted: Tue Mar 16, 2010 3:08 pm Post subject:

Sorry to resurrect this thread once again (actually I'm not really that sorry)!

I'm having the same problem xpmtl had. Did he ever get it sorted out? I just built 2 more bugs with the group buy pcb's, with the idea of having them behind a dual panel with all the extra features found in the wiard version. With both of the first 2 I built, I didn't wire up the lfo out jack, but I have with these new ones. However, the output seems pretty useless - stuck at 5v, with little dips to about 4v at the clocks (like the diagram xpmtl put up a page back) - seems inverted from what it should be.

And I'd also like to wire up an led from the lfo rate with the cgs pcb, but with that always-on voltage, the led doesn't really do much. I'm going to try some alternate places to connect the sensor wire for the led, but I'd still like to sort out the lfo out problem to make it usable.

Any ideas?

Edit: bump - I hope someone has some ideas about this!

sduck · Posted: Wed Mar 17, 2010 2:55 pm Post subject:

I tried running the lfo out through my cgs inverter and got the behavior I expected - short positive 5v pulses at the clock, 0v in between, and the led behaving correctly. So as the circuit is really simple, I'll just breadboard up 2 of those and hook them up behind the panel.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

What are people using for the 1M potentiometer taper?

I'm thinking log would work best.

Dave

sduck · Posted: Thu Mar 18, 2010 3:24 pm Post subject:

I used linear ones, but now that you mention it, log ones might work better - there seems to be lot more change near the top end of the rotation. However, given the random nature of the device, getting a precision setting on the dials is of a low priority for me, so I won't be changing them out to see if it makes a difference.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

I've started building my Wogglebug PCB. I've created a web page with a Mouser part number list, photos, and other information. I'll continue to update it as I complete the module. Since I'm still building the PCB I haven't yet verified all the parts.

I was unable to find a set of schematics with the correct pin and reference information for U5, U6, and U7 so I edited the schematics myself. I also included the stability modification for U3. I posted this update on my web page (let me know if they already exist somewhere on the web).

So far I've only implemented two additional modifications - changing the LFO Out to a Clock Out, and adding a LED indicator for the Clock Out. The LFO Out was a +/- 5 volt 7.4 mS negative pulse that I thought would be more useful as a 0 to +5 volt positive pulse to use as a variable clock / trigger generator.

http://modularsynthesis.com/bridechamber/wb/wb.htm

Dave

sduck · Posted: Fri Mar 26, 2010 1:49 pm Post subject:

Very nice! I'm guessing you haven't gotten around to adding the cluster cap cludge to your list of add-ons - I'm pretty sure you know what I mean. Every one of mine has needed it to get the cluster knob working.

Edit - oops, now that you mention it I see you had it there all along. Sorry.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

sduck · Posted: Fri Mar 26, 2010 7:03 pm Post subject:

I've never considered the range of the cv outs to be too much. I'd leave them at 10v - you can always attenuate them down if desired.

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

After using my Wogglebug for a bit, I decided I wanted the clock out to be a 50% duty cycle. The rate is plenty fast so I decided to divide the output of the 555 by two to generate a square wave. I made a module using an 8 pin DIP header, a LM555C, and a 74C74 that plugs right in place of U4 so there are no modifications to the PCB. Three of the 74C74 pins line up with the LM555C so there are just a few pins to hand wire.
Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

I added the details to my Wogglebug page.
http://modularsynthesis.com/bridechamber/wb/wb.htm

Dave

slacker · Posted: Wed Apr 07, 2010 10:13 am Post subject:

That's brilliant Dave Smile

xpmtl · Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium

sduck · Posted: Wed Apr 07, 2010 7:21 pm Post subject:

Thanks! But I went ahead and made a little inverter board and hard wired it back there, and it works great. I only discovered the problem after I had installed everything, and using the addon board made a little more sense than taking the whole thing apart. I knew the addon board was going to work, and I wasn't so sure about the other kind of fix, so the choice wasn't too hard. However, I'm sure your fix will help someone else down the road, so it's all good!

tommi · Posted: Thu May 06, 2010 9:32 am Post subject:

Since i am waiting for a PCB from bridechamber i am documenting myself for all possible modifies for the wogglebug. I 've seen different solutions for the clock rate led. The simplest seems to be the one from davebr: 3k3 resistor from pin3 of U4 (lm555) to cathode, +V to anode. I think i 'll try this one.
Also, as written by sduck on the top of this page:

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

tommi · Posted: Thu May 06, 2010 11:48 am Post subject:

Thanks davebr, i think i 'll do the inverter modification, it will do the job of triggering out short pulses for sequencers, etc.
The 555 will still be clocking U3(LF398) thru R27. In place of R40 (49,9K) there will be a 300k resistor. Another 300k resistor from +in to -V. One 100k on the feedback path and the -in to ground. Is that right?
Is it tricky to do? How many traces to cut?

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

tommi · Posted: Fri May 07, 2010 1:43 am Post subject:

Thanks dave,
Looking at your picture of the populated board ( i was searching for details of your mod) it seemed to me that this modification wasn't yet done.

Anyway, in your answer it's all clear for me except for you said that R27 stays connected to pin 1.
On your WB's schematic R27 is linked to the 555's out on pin 3, not to pin1 of U6 (this is what i thought you was saying?).

I guess you was meaning that R26 stays linked to U6, pin1?

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

tommi · Posted: Fri May 07, 2010 8:27 am Post subject:

Dave,
Since the led it's directly linked to the out of U4 (pin3), i think that in case of external clocking it will still indicate the rate of the internal clock. This would be distracting...
I thought i could add an led circuit (cgs led driver?) to pin7 of U6B (the amp stage of clock in) to indicate the actual rate at wich the circuit is clocked.
Maybe i am wrong on the interpretation of how your led is ment to behave?

davebr · Joined: Jun 09, 2007 Posts: 198 Location: portland, or

tommi · Posted: Fri May 07, 2010 8:53 am Post subject: