[BUILD] 100m-ish LFO

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: luketeaford, Joe., lisa, Kent

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

[BUILD] 100m-ish LFO

Post by fitzgreyve » Fri Feb 12, 2016 5:41 am

27/09/16 - attached build doc updated

It's a 100m LFO on the outside, but not on the inside :hmm:

This LFO is intended to replicate the user interface and most of the behaviours of the Roland 100m LFO (as found in the M-140 and M150 modules).
However, the internal circuitry is totally different to the Roland – it’s PIC based, using code derived from the Electric Druid VCLFO9D (used with permission).
Features:
- Exponential response, 1V/Octave, resolution is 32 steps per octave.
- WAVE – sine, triangle, pulse, rising ramp, falling ramp.
The pulse is positive (+5V) only, as 100m.
Other waves are +/- 5V.
- RATE - frequency control – about 3.8 octaves
- RANGE - switch:
H range RATE control gives ≈ 2.5Hz to 26Hz
M range ≈ 0.2Hz to 3.5Hz
L range ≈ 0.05Hz to 0.25Hz
- RATE CV - input with attenuator :
The LFO has an overall 8 octave frequency range.
- DELAY - an external gate signal (can come from Doepfer bus connection) will trigger a fade up of the LFO amplitude.
normalising the CV input socket to the DELAY envelope output allows the LFO rate to speed up as the LFO amplitude increases.
- SYNC - positive sync input (+5V). Resets the LFO. All the waveforms sync to the correct phase as the 100m.
- /10 - divide by 10 switch. Reduces the LFO output.
- Normal and inverted outputs.
- Optional PIC code for a “hidden” noise with sample & hold waveform.

Prototype (production panel is slightly different - the /10 switch and sync input swap posiitions):

Image

Prices:
PCB GBP 8
Panel GBP 14
PIC GBP 3 (programmed and tested)

UK shipping included, international at cost

PCBs and PICS available now, there is a delay for panels.
You do not have the required permissions to view the files attached to this post.
Last edited by fitzgreyve on Mon Nov 07, 2016 10:06 am, edited 7 times in total.

User avatar
woodster
Super Deluxe Wiggler
Posts: 1341
Joined: Mon Mar 05, 2012 9:36 am
Location: UK

Post by woodster » Fri Feb 12, 2016 6:54 am

I'm interested. Was thinking I need another LFO

StormB
Learning to Wiggle
Posts: 36
Joined: Fri Oct 02, 2015 4:02 am
Location: Germany

Post by StormB » Fri Feb 12, 2016 7:17 am

Hi,
Im in for 2PCB and 2Pic´s
Thanks
StormB

User avatar
Electric Druid
Common Wiggler
Posts: 114
Joined: Sat Mar 31, 2012 1:20 pm
Location: UK
Contact:

Post by Electric Druid » Sat Feb 13, 2016 8:52 am

I'm an Electric Druid, and I approved this message!

The additions to my code look great. Particularly like the fade-in/speed-up feature. Very cool.

Tom

Grumskiz
Wiggling with Experience
Posts: 346
Joined: Thu Apr 03, 2014 12:51 pm
Location: Germany

Post by Grumskiz » Sat Feb 13, 2016 8:58 am

Hi, I'm also interested in one PCB and PIC.
Just wondering: Is the Roland logo on the panels you sell? That might be a bit risky, even for small non-profit runs :S

User avatar
Reality Checkpoint
Confused By Electricity
Posts: 3905
Joined: Wed Apr 15, 2009 4:06 am
Location: Al Aqsa

Post by Reality Checkpoint » Sat Feb 13, 2016 9:34 am

Definitely in for one panel/pcb/pic set to add to my crushing backlog!

User avatar
whoop_john
Veteran Wiggler
Posts: 689
Joined: Sun Mar 17, 2013 12:03 am
Location: London UK

Post by whoop_john » Sat Feb 13, 2016 3:48 pm

Interesting and very good work.

I don't understand how the Gin to Dly0 works. Are you reading pin 10 as an input, sensing a gate in and then switching pin 10 to an output, sending a voltage to Dly0 via the PIC?

Any expansion on the operation of this feature would be appreciated.
'tis the pigeons that alight
on Nelson's hat that makes it white

User avatar
Synthsense
Common Wiggler
Posts: 217
Joined: Sun Nov 04, 2012 12:40 pm
Location: VCAlona

Post by Synthsense » Sat Feb 13, 2016 3:57 pm

I'm in for one panel/pcb/pic set please

Cheers! :guinness:
Last night I lay in bed looking up at the stars in the sky and I thought to myself, Where the heck is the ceiling? :hmm:

User avatar
leeski
Super Deluxe Wiggler
Posts: 2109
Joined: Sat May 12, 2012 5:44 pm
Location: Saturn

Post by leeski » Sat Feb 13, 2016 4:05 pm

i'd be interested in panel/pcb/pic, looks good :tu:
«:::A:::» «:::W:::» «:::E:::» «:::S:::» «:::O:::» «:::M:::» «:::E:::»

User avatar
leeski
Super Deluxe Wiggler
Posts: 2109
Joined: Sat May 12, 2012 5:44 pm
Location: Saturn

Post by leeski » Sat Feb 13, 2016 4:05 pm

Ooops double bubble :cry: :tardis: :tardis:
«:::A:::» «:::W:::» «:::E:::» «:::S:::» «:::O:::» «:::M:::» «:::E:::»

User avatar
PWM
Ultra Wiggler
Posts: 974
Joined: Wed Feb 27, 2013 6:08 pm
Location: Amsterdam, The Netherlands
Contact:

Post by PWM » Sat Feb 13, 2016 5:03 pm

The image of your panel is all croped up..
On my iPhone, that is.

User avatar
Outtatune
Wiggling with Experience
Posts: 284
Joined: Thu Oct 08, 2015 7:27 pm
Location: Singapore

Post by Outtatune » Sat Feb 13, 2016 8:25 pm

That Rate CV In is expecting a Clock or Square signal, right?

User avatar
whoop_john
Veteran Wiggler
Posts: 689
Joined: Sun Mar 17, 2013 12:03 am
Location: London UK

Post by whoop_john » Sun Feb 14, 2016 5:21 pm

Outtatune wrote:That Rate CV In is expecting a Clock or Square signal, right?
Wrong. Unless you want only a dual speed LFO corresponding to your Clock or Square high and low levels.

Rate CV, as its name implies, is an analogue input expecting a variable control voltage.

It says in the documentation it can take 0v - 8v in but it converts this to 0v - 5v for the PIC to process., VR5 adjusts the 1v/octave response.
'tis the pigeons that alight
on Nelson's hat that makes it white

User avatar
sixty_n
Wiggling with Experience
Posts: 313
Joined: Sat Nov 08, 2014 8:28 pm

Post by sixty_n » Sun Feb 14, 2016 6:06 pm

interested in one set

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

Post by fitzgreyve » Mon Feb 15, 2016 5:11 am

Is the Roland logo on the panels you sell?
- No, those are for my personal use only! Production panels have my logo (see the build doc front page)
I don't understand how the Gin to Dly0 works. Are you reading pin 10 as an input, sensing a gate in and then switching pin 10 to an output, sending a voltage to Dly0 via the PIC?
PIC pin10 ("output level") reads the voltage on C7 (the delay envelope) - the leading edge of a gate pulse (Gin) resets this to 0V via Q1, it then charges back up to +5V via VR3 (delay). U4 just buffers the voltage on C7 to provide "DlyO". Pin 10 only reads the voltage - it's never an output.
That Rate CV In is expecting a Clock or Square signal, right?
It's a Control voltage input - it's summed with the "rate" pot voltage before being read (as an analogue input) by the PIC.

User avatar
drip.feed
Roll it off at 30 Hz
Posts: 3179
Joined: Thu Sep 15, 2011 10:05 am
Location: Belfast, Northern Ireland

Post by drip.feed » Mon Feb 15, 2016 10:53 am

Hi Mark, I will take 2 complete sets (pcb, panel and pic). Thanks! :tu:
Dripfeed

User avatar
Dimitree
Veteran Wiggler
Posts: 667
Joined: Mon Aug 01, 2011 9:59 am

Post by Dimitree » Mon Feb 15, 2016 11:18 pm

A bit off topic, but, does anyone knows if the sawtooth/ramp waveform on the original 100m LFO has the same frequency of the other waveforms, or half the frequency (like on some LFOs, since sawtooth is derived from square and triangle)?

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

Post by fitzgreyve » Tue Feb 16, 2016 4:09 am

Dimitree wrote:A bit off topic, but, does anyone knows if the sawtooth/ramp waveform on the original 100m LFO has the same frequency of the other waveforms, or half the frequency (like on some LFOs, since sawtooth is derived from square and triangle)?
Looking at the Roland book "the synthesizer" ,and the schematic, I would say with a very high degree of confidence "same frequency".

User avatar
drip.feed
Roll it off at 30 Hz
Posts: 3179
Joined: Thu Sep 15, 2011 10:05 am
Location: Belfast, Northern Ireland

Post by drip.feed » Thu Mar 31, 2016 8:34 am

Hi Mark...any progress with these? :guinness:
Dripfeed

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

Post by fitzgreyve » Fri Apr 01, 2016 2:49 am

drip.feed wrote:Hi Mark...any progress with these? :guinness:
Delivery of the panels should be confirmed in the next few days.

User avatar
drip.feed
Roll it off at 30 Hz
Posts: 3179
Joined: Thu Sep 15, 2011 10:05 am
Location: Belfast, Northern Ireland

Post by drip.feed » Sat Apr 02, 2016 2:19 pm

fitzgreyve wrote:
drip.feed wrote:Hi Mark...any progress with these? :guinness:
Delivery of the panels should be confirmed in the next few days.
Lovely. What's the width of the panel, 8hp?
Dripfeed

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

Post by fitzgreyve » Sun Apr 03, 2016 4:51 am

drip.feed wrote:
fitzgreyve wrote:
drip.feed wrote:Hi Mark...any progress with these? :guinness:
Delivery of the panels should be confirmed in the next few days.
Lovely. What's the width of the panel, 8hp?
Yes - 8HP

User avatar
fitzgreyve
Veteran Wiggler
Posts: 508
Joined: Mon Jul 15, 2013 4:49 am
Location: UK

Post by fitzgreyve » Wed Apr 27, 2016 5:10 am

Panels are now in - PM's going out very shortly to those who expressed an interest.


For those waiting for my Polymoog res and VCO driver, I have the panels, but ITEAD are being remiss with the latest PCB delivery - keep watching.

User avatar
drip.feed
Roll it off at 30 Hz
Posts: 3179
Joined: Thu Sep 15, 2011 10:05 am
Location: Belfast, Northern Ireland

Post by drip.feed » Wed Apr 27, 2016 5:14 am

fitzgreyve wrote:Panels are now in - PM's going out very shortly to those who expressed an interest.
Schwiinnnnnnnnnng! :nana:
Dripfeed

User avatar
GryphonP3
Super Deluxe Wiggler
Posts: 1096
Joined: Tue Jan 29, 2013 3:20 pm
Location: Los Angeles

Post by GryphonP3 » Wed Apr 27, 2016 12:42 pm

I'm in for one full set please.
My cat can eat a whole watermelon ...

Post Reply

Return to “Music Tech DIY”