1) The first order of business is a battery pack so I don't have to plug in all of the time. Plugging in is really inconvenient and sometimes impossible
    without carrying a 50 foot extension cord (been there, done that!)

2) The second option is a custom pedal-6 for the new firmware upgrade. I'll admit I haven't purchased TC's pedal 6, not for the fact that I'm pretty cheap
    but because I want more control over the VLT2 than they have offered. This is why the pedal-6 will have:

  -Standard 6 switches for regular pedal 6 control
  -MIDI output to send MIDI messages to control the VL2, modify-able via MIDI Sysex from regular .txt file
  -MIDI input / merge to allow other controller's data to be forwarded to the VLT2

SO, on to the battery pack first as I've just completed it!

Battery Pack for the VLT2

I had originally thought of using a pair of standard 4-battery holders and a double holder, taping them all together, but that's so ugly and
problematic. As I have a 3D printer, which is somewhat of an addiction for me, I thought "why not print one up!"

The 1mm indents for the Clips are slightly oversized to accommodate larger clips than I used here. The clips are from a bunch of solar lights I bought to tear off the little panels for something else, but they're only a buck each so...

The opposing clips were soldered together and glued into place. I found that with my printer, the battery holes became smaller than anticipated as well as Duracell NiMH are way fatter than regular batteries, so the holes needed to be filed.

Being paranoid, I series'ed a 10V zener +diode+100 Ohm resistor + yellow LED to drain off the high voltage post-charge state of the batteries down to 12.8V. It's kind of useless though as the VLT2 starts up at 13.6V no problem!

I found a nice little barrel connector to plug into the VLT2. Don't ask me the size as I have no idea on those numbers or designations!

*NOTE:
Do not use regular batteries as this will result in 15 Volts which may damage the VLT2! I don't know for sure if it would, but using a pair of dummy batteries (wherever you get those) would make 12 volts again.

**NOTE2:
The Barrel connector is reverse polarity! The outside is (+) while the pin in (-). This sucks for me as I have at least 10 pieces of studio kit with that same connector but normal polarity.
Hopefully the VLT2 has reverse protection circuitry...

Test results:

Conclusion:
We know the VLT2 can run for around 3 hours off of fully charged 1200mAH NiMH batteries. I don't know if I'd run it too much longer as it isn't designed for a slow voltage drop and may start outputting distorted artifacts etc. I imagine the processor has an LDO regulator of some sort so won't be an issue until extremely drained.

The fit into the VLT2's bracket is tight, but the exposed cover (end) is slightly shorter to facilitate removal of the cover, and also to allow the rest of the case to act as a retainer. It won't fall out. I have thought about putting a tab off of one of the lower screws to further limit movement of the pack without gluing or affixing it.

PEDAL-6 for the VLT2

  As mentioned above, I was about to buy a Pedal-6 when I realized it wouldn't meet my needs in the studio or on stage. I play acoustic instruments (guitar, sax, piano, pan-flute, accordion, etc) that requires both hands constantly, so reaching to tap a button is almost impossible. Believe me I've tried!

With custom MIDI control, about 90% of the panel controls can be controlled via MIDI CC's. This is way better than just the pedals which I'd say is about 30%.

Custom MIDI Hardware Benefits:
- Harmony level can be controlled with two pedals  with a set rate of increase/decrease i.e. 3 seconds full range. This is a personal must.
- Guitar gain, Aux Level, Filter can be cycled as above.
- Harmony Voices can be added/removed in a cycle for "thickening" a chorus. i.e. 1 tap=+2 voices, 2nd tap =+4 voices, 3rd tap= 0 voices
- Loop sizes can be quantized on a clock input (trigger & MIDI) to 4's or 8's etc. Or even terminate automatically.
- Fast FX such as sync'ed tremolo or EQ'ing can be realized by applying a software LFO->CC on selected level
- Multiple actions on a single pedal i.e. toggling between VLT2 Presets and starting a Loop Record
- Complex sequences i.e. alternating or sequencing  delay/reverb/pan/transducer with internal sync'ed LFO phases.
-4 MIDI Pedal layout presets selection. 7th pedal to step through them and normal Pedal-6 operation.

Hardware:
I've decided to build my own Pedal-6 from scratch using 3D printed footswitches. This design would work with a normal pedal-6 case or
a box with footswitches, I just don't much like those switches "click-click" & hard on bare feet!

- The main processor in the circuit will be a simple Arduino Pro-Mini (ATMEGA-328) for easy programming.
- For convenience, the MIDI interface will by powered from a 9V battery (or 6 AA's) but switched through a barrel connector socket for ext. pedal power.
- The VLT2's footswitch lines will be switched over to the processor using a mini latching DPDT relay so it isn't a constant power draw.
- An opto-isolator (6N137) and transistor driver will facilitate the MIDI I/O
- For Eurorack Modular patching (or Beat Step Pro etc) there will be a Clock input and two trigger inputs (possibly a CV input too!)
- Small EEPROM (as pro-mini has no self write) and a MAX7219 LED driver (has dimming capability)

Software:
As I've written lots of MIDI stuff for Arduino's this will be an easy and enjoyable thing to program. It'll be a nice break from the complex programming I do for money.
I'll make the code open source and anyone is welcome to post alternates. The main points of the software are:
 

When pressure is applied to the footswitch head, the switch is actuated once it moves about 1/4". Under the head of the switch a heavy spring will be mounted. This is for the "feel" of resting a foot on the switch without accidentally activating it.

The heads are about 1 1/4" high to be able to go through 3/4" plywood (or cedar) and the surface panel (below)

The switches must be soldered on the other side but they fit fairly tightly in place so shouldn't need gluing.

The White pedal is semi-translucent so could be illuminated if required. This is all "by gosh & by golly" really!

Here's the .stl's (and .obj's) for the pedals and switch mounts:

VLTpedals.zip

These panels are held in place with #4 wood screws, quite a few of them. Better safe than sorry! I have completed these panels but as they are black they show poorly in a photo for reference.

I put some raised lips around the LED holes to protect them from footin'- puttin' as the panel is only 1.6mm thick (to save plastic, money, and the environment!)

Under each pedal is an LED that may indicate active pedals or pedal states. I may use RGB LED's here. As these holes are 3mm and the RGB LED is giant at 5mm, they my need to be dremelled down to fit the holes. It was an after thought...
of course bi-colors could be used as well..

Between each pedal is a set of LED's or LED's and a button switch. (not sure yet)
If set up as 3 LED's then 2 pedals could share them in and up/down scenario, LED's as a simple bar indicator.

The little frames are for marking pedal functions. These will be painted silver so black felt pen can be used and erased with alcohol if required.

The lower picture here shows the general arrangement of the panels. The center is of course for the white 7th pedal. This pedal will control MIDI<-->Pedal-6 modes and likely MIDI presets 1 to 3 or 4. Pedal-6 mode will turn off all of the LED's to minimize draw. The power switch (which will be on the back me thinks) can then be turned off as the latching relay will be in normal pedal-6 position.

The .stl's & .obj's for the panels are at VLTpedcovers.zip . I must mention that these footswitches are 60mm apart only, which suits me as I don't have "man feet" but if you are going to use these .stl's, the actual sizes can be larger up to 30%? the pins on the 12X12 button switches may need a bit of bending but hey, you won't have to drill out the 3mm LED holes larger!

This diagram is the basic idea of it. It's not super complex! The pedal-6 uses a resistor ladder and when switched over, so can the Pro-Mini in the same way. There will of course need to be some timing and de-bounce routines internally, and perhaps an RF trap before the ADC input.

The modular inputs (clock, trigs, CV) can be used to trigger events from eurorack modular signals. The primary for usefulness is the clock. The CV input could be used to control VoiceLive's harmony key along with a VCO let's say..

So that's about it for now, gotta go! I'll post proper schematics & more specs etc. once they are done.

Had some down time over the week  so fabricated a case and worked out the jack arrangement. As the diagram above shows there are jacks to interface with eurorack modular so I decided to keep them all together and recess them with a 3-D printed panel. I have added a clock output (to work with MIDI) and another CV input. There's a couple of extra jacks for whatever other  ideas that will pop up in my head between now and completion of the MIDI side of the project.
 

The springs for the pedals must be mounted at an angle to follow the case, so I 3D printed mounts for the 6 pedals, and a little one for the center (MIDI) pedal.

The other jacks are MIDI I/O. This MIDI out will of course patch to the VLT2 but the MIDI in can come from a DAW or controller. As the VLT2 is the end of the line MIDI-wise, I may add another jack splitting off, not sure yet. The pedals will send their control data but I also want DAW control over some functions so in a way it's an internal MIDI-merge.

>>To the right is the PC board mount that stands on little legs to clear the center pedal. I'll show more of this shortly. The little PC board shown is temporary with just the standard Pedal6 circuit.

Below that photo is the 12x12 tactile switches wired and ready to install. The aren't in yet, perhaps tomorrow. I've decided to mount all of the switches to a  length of aluminum angle as I don't want to pop 14 holes through the nice case!

Below is the case pretty much finished. 3D printed a guard for the front edge (as it *is* wood) from PLA that wraps around as a protection. . The little "windows" are for marker pen and arrows in case I forget the last configuration! Alcohol will remove it.

I'll post my experiences with the basic pedal 6 arrangement first. Until next time, cheers!

It's been a while as I have nearly no time to do my own projects but I finally got around to wiring up the Pedal 7 with the really basic board which is the components to the far left (10K resistors etc).

It works great!

As can be seen, the the proposed schematic has grown a lot. This is to mainly integrate an SDS On_Tap into it, and the extra MIDI port so the chip had to be changed to an Atmega which has 4 USART's, lots of I/O and could be just the Atmega arduino board. In my design it will be integrated but if you decide to build this project then an arduino board can be used.

Anyway, the SDS On_Tap:
It was for a while a secret design but will be integrated into Arduino .ino sketch so won't be secret anymore!
The On_Tap is similar to the Beat Buddy (although invented long before it) in that a drum sequence can be controlled by 1 foot on a peizo pedal. A switch pedal could be used, but I prefer the flatness of a peizo pedal. (I built a dual heel-toe pedal, so there's 2)

The key feature of the On_Tap is that the beat can be inserted after the song is underway, i.e.
Playing an intro on a guitar, a few bars, then start tapping on the pedal and (optionally) a kick or other drum starts playing at the tempo you tapped.
A preset lead-in and drum sequence starts playing after the set number of beats or bars. The tempo can be sped up or slowed down in a similar way to a tap tempo button on many devices.
To set a stop (end of song), just double tap or triple tap to the last beat. To pause at bar, just tap once.

So back to the Pedal project...
The display has been added (Tayda 3 digit) to select On_Tap beats plus do other things like MIDI learn mode. I didn't want a display but there it is!

VoiceLive Touch2 "Notes Mode":
I have discovered a frustrating thing about the VoiceLive. The MIDI notes mode only does harmonies while the keyboard keys are down! This is OK if you are playing a MIDI keyboard exclusively to manipulate harmony voices, but I play the music on the piano and sing along. I had assumed it would be like playing a guitar into the VLT2 and the harmonies following and remaining in place. Not so.

In the MIDI programming I'm going to have to insert a "sustain" message, or just lock note-on's (up to 4) with timing so the harmonies are changed as I change chords in the piano. This seems simple enough, but might not be. The way I play, mostly, is the chords are changed by releasing all keys but sometimes I hold a key or two and change. This will need to be detected to release old notes and replace them with new ones. Always in 4's as this is what the VLT2 likes.

Another issue: Keyboard limit(s)
In the VLT2 there's only 1 keyboard split. I set mine at F3 so any notes below F3 will not make a harmony. Problem is I sometimes switch up an octave with my right hand and suddenly I'm singing with Alvin and the chipmunks! This not only sounds silly, but tends to resonate more than the lower harmonies being I'm female.
The solution is of course to pop in a second MIDI notes limit on the VLT2's MIDI channel.

The EEPROM:
The EEPROM is going to be larger because it must hold up to 100 drum sequences, and they are running at  24 "frames" / beat  up to 64 beat loops (maybe larger) plus the lead-ins. That's 160KB or so a 2 MBit will be needed, perhaps a  M95M02-DRMN6TP. MIDI files will be directly recorded in along with the MIDI clock to avoid the annoyances and time overhead of an SD Card. (Not that I haven't done *that* before!)

Quickly things are getting complex, but it seems really logical to integrate the SDS_On_Tap as I've been meaning to retire the old one that has a more limited memory.

Dec 1st 2018 Update:

After a long period of doing other things, I have decided to continue the "Pedal 7" project!  I have been using it as a pedal 6 for the last few months but am ready for more features (as with the previous design) but have added even more since:

1) SDS_Tap built in as before but does Drumloops + Entire MIDI Songs. Also sends control & sync to VLT2 as before.

2) A built in sample player. This will not only augment the MIDI drums with real sounds but can do entire loops. Sample memory is SD Card based but holds over 20 minutes of audio without SD Card. This is to avoid SD Card latency issues too.

3) Audio EQ. External audio can be fed in and run through the sampler EQ for level and FX that can be MIDI-song controlled. The Main audio out will go to VLT2's audio in.
 

 The flash PCB is actually a PIC controlling a 128Mword flash from one of my products, the Reflex LiveLoop Expansion board.  The Atmega basically gets the MIDI song/drumloop data from the flash also, and then loads that into the 1Mbit SRAM via i2c.

Samples are handled / mixed by PIC18F46K22 on the Flash board, (I'll post a schematic of that eventually) then send onto the bus of this board to the stereo 16 bit DAC (hidden inside box also). The ADC5547BRUZ DAC is rather expensive ($28) but I had a few extra kicking around so used one of them.  The bidirectional level shifter (2x8) is a 74LVC4245A that also protects the Flash PCB's bus.

For the Atmega chip I ended up using a little breakout board that greatly assisted in the design on a single sided PCB. The PCB was photo-etched (made larger via's in KiCad) then CNC'ed the holes. This was the first time I've ever crossed the two methods and it worked great! The only difficult part was getting the PCB image size correct so the CNC wouldn't end up drilling holes outside of vias and other horrible things.

I will also post the KiCad schematic etc. as this is only a basic description and I have little time at the moment!

Cheers,

Sandy

Well it's been a while!   I have the Pedal-7 finished (as of Feb 25th)  but find it hard to stop as I have been using all of my spare time on this project.
It didn't go along without any problems though, Atmega crashes, Sampler lockups, mysterious MIDI issue (kawai keyboard sending sysex's!), pedals grinding against the frames, near fatal bus retention, etc etc etc. but it's reliable now and even with Eurorack Modular interface keeps tempo & sync.

This is totally  going to sound like a bragging session but, if you have a VLT2 or are designing a hardware MIDI sequencer this will be of interest.
There's been a few changes as the project proceeded...

VLT2
The VoiceLive Touch 2 VLoop control has been changed in a way I hadn't expected. I had originally wanted to set the Metronome to "Shh" so it would keep time with incoming sync, but I noticed two bad things:
  1) The Metronome resets on power-up so needed to be turned on and set to "Shh" every time.
  2) The VLT2 counts MIDI clocks from the Play message, which is logical, but only quantizes starts and stops to the nearest (next) beat.

The latter presented a real issue for my singing & looping style. I tend to begin singing, or sing the downbeat slightly ahead of the actual downbeat ( this is normal in swing styled rhythms ) so it would chop of the very first bit of my vocals or cycle at a point that I couldn't well duplicate to close the loop. I know common looping practice is to "run into" the start of a loop, then run into it again for a moment to close any gap at the end, but this seemed and felt very limiting!

It also caused a slight problem with a MIDI sequence controlling the Looper. One would have to be careful to leave some time before ( >1 beat ) starting the loop and measure that time for ending it. Because of this, Loop re-triggering FX are out, and so are pauses in the loop as they will start at the wrong part of the loop. Ugg!

So the solution, as ugly as it seemed at first, was to use the MIDI sequence (Song or DrumLoop) running in the Pedal-7 to quantize to the following 1/24th of a quarter note (which is standard MIDI clock timing) and quantize to bars! That's an "arm to end" on every 96 clocks. So no matter where the loop starts, it will always align to the next bar in the same offset position.

So... how will the VLT2 stay in sync with the Pedal-7 if the metronome, aka clock sync ability, is disabled? Well, simple...or so I thought. Use the VLT2's Looper Play re-trigger command to keep the alignment.  This did not work as well as I'd hoped. I guess it's to do with an oversight on the VLT2's internal timing while under MIDI control. Dealing with Play re-trigger in normal case use is via a finger-touch on the Keypad, which can be out up to 50mS either way because of human error, finger velocity etc.
But under MIDI control, this variation becomes more obvious. Sometimes it *would* be out by as much as 50mS!

OK, so it doesn't work then?!  No, it does work if there's no sync. I discovered that my internal MIDI sequencer timing is so accurate, it will track within 1/4 second over 10 minutes! This is without fail. So I implemented a "sync request" on the Alternate Pedal switch (center pedal switches to 2nd set of pedals) that will do a re-trigger Play on the next loop point if desired. The Play re-trigger works perfectly now as well, doing breakdowns with your foot is fun ( and challenging ha ha! ) when being creative.

Sample Polyphony:
I managed to squeeze 6 channels out of the sampler ( 3 x -stereo)  so it works well with percussion, but couldn't help but make a mono-synth (Sample rates quantized to MIDI notes) to play recorded synth, bells, toned percussion, vocals etc! It seemed the next logical step, but I hadn't counted on two cool FX with this mode:
 1) The mono-synth plays the last sample selected on the Sample Channel, but if two are selected the first will continue playing through the notes!
 2) If a longer sample (i.e. vocal phrase or chime) is selected, then a non-assigned note (no sample) the first will play through but following MIDI notes
   *Here's a sample of both of these using vocals (sorry about my goofing around lol) and variable sample start offset control in the sequence + VLT2 looping/FX.

MIDI Loop Recorder:
This added machine will record a live loop (mostly piano for me) of incoming MIDI while the sequence is playing which is perfect for DrumLoops. I start a drumLoop by Play button or tapping a tempo while sitting at the piano, then hit the Pedal assigned to arm the MIDI Loop Recorder. On the first note played on the piano the loop will begin recording. To end/close the new piano loop just tap on the pedal while inside the last bar and it will begin playing on it's own downbeat (again as with the VLT2 Looper not dependent on a true beat marker). Pressing the same pedal again will re-arm it so a modified loop can be played in (any length). Holding it for a second will end the loop on the next cycle so it's predictable where to take up playing "for real" again!

I can see this useful if I want to switch to guitar or some other instrument but keep the progression going. I don't know how much I would use this live, but this Pedal can be controlled via MIDI so could be armed & ended by a playing song, which is a more likely scenario.

Live Self-Clocked Recording (with metronome if Desired:
I know most of you have probably left the page by now, and I can't blame you, but I must add a couple of more changes before moving on!
I have always wanted a simple (preferably no computer) way of recording a piano session in real time. Granted, my little Kawai will do this, but not my Roland (more real) piano. If I hold the button used to arm for recording  a MIDI Song or DrumLoops, it becomes armed for self recording. At this point I can simply play and tempo doesn't matter (even though playback can be sped up/slowed down, it won't sync) or I can set a tempo and start the classic "Bell-tick-tick-tick" metronome from the percussion channel and play to that. For me this is odd as I'm totally unaccustomed to playing along with a metronome ( they don't swing enough!! ) but probably good experience...

I have recorded a single session over 45 minutes this way, and it'll hold 100 Songs and 100 DrumLoops!

True Live Notes MIDI Harmony:
I love singing harmonies into the VLT2, it's my favorite thing and why I bought it in the first place. The guitar & room sense harmony control works pretty good I must say, but not so much with piano... especially the way I play (I guess that's it!) so I decided quite a while back to try the MIDI Note controlled harmony feature. Right away I was put off by the way the harmonies only happen when the keys are held down. For some reason I thought it would carry through until different notes are played, but, like with Arpeggiation, this is a lot harder to achieve than one would think! For example, which note changed constitutes a harmony change? When and how long should the harmony hold for? This will change drastically with the player so I lay no blame on TC Helicon at all. Globally it's impossible!

For my own use on the other hand, I know my playing style so could fashion an algorithm to suit. In a simple view, this amounts to the following:
1, 2, then 3 (maybe 4) Notes come down and lock the harmony until they are all released. If, within 100mS the same notes are played again but with a single different note, the previous note will be included.  If rolling through notes, all notes are considered  part of the harmony as long as they are not lifted for more than 100ms before another note is struck. This way you can alternate between C and E+G and have a harmony of a C triad, or if alternating to a C7 by lifting the keys this isn't going to be a problem.

I have also created my own harmony keys range (that can be changed by each song/DrumLoop Loaded if required) rather than just High or Low keys offered in the VLT2. As a woman, most times I don't want baritones harmonizing with me, or pixie babies, just other girls my age! As I am all over the keyboard neither is good for me, so a "window" of opportunity was to create a window of notes!

The MIDIPLUS Mini-Engine Pro:

In the "Light Setip" diagram at the bottom left corner is a little GM MIDI box that is about $80 US, made in China, and sounds great! The reason it sounds great is because it's using the Dream (TM) France SAM5504 chip (along with an STM32F40(5?) microcontroller, even though the Dream chip doesn't need it.)

Each Channel (including percussion) has a Cut/Rez Filter, standard vibrato mod wheel etc, and  A/D/R envelope controls! Quite a lot for $80 eh? ($4530 CAD)  It is 32 bit so sounds very nice indeed. Stuff sounds real and can be modified into our favorite electronic music instruments by monkeying with the above controls.

The down side is typical Chinese buggery. Even the the Dream chip can handle multiple instrument access, several drum kit variations, and other features, whatever firmware they have put into the STM chip kills it. Perhaps for future model feature releases (ugg!) or just because they had no idea what they were doing.
Another nasty is sending any bank select or Program Change message on channel 10 will turn the drums into a piano requiring a factory reset to get the drums back. If any white button is pressed while drums are playing it will turn into a piano. Sloppy of them really!
Why is it whenever the word "PRO" is in the name of a product, it ain't ?

I could go on and on and on about the Pedal-7, for pages and pages ( well 34 pages - here's the user manual for ideas!! ) but I won't.

Suffice to say, this is the "funnest" thing I have ever made.

It can hold 100 Songs, 100 DrumLoops, all tap tempo playable and variable, can be re-clocked on the fly via external Eurorack Modular clock ( great for fast-forwarding! )  or DAW Sequencer ( resets to start instantly) , it can provide a clock for other MIDI instruments or Eurorack Modular, can hold up to 100 directories with 100 samples in each, has 12 accessible Pedals assigned with any of  31 functions, sends Trigger/Gate pulses from any Clock Division or notes in a MIDI Sequence, saves and updates Song/DrumLoop parameters & Options via SysEx files on an SD Card, has a SD Card SYNC function to add samples or update default/Dong/DrumLoop parameters automatically, can output Control Voltage (via CC or Quantized from MIDI Notes), can read trigger/gate inputs to control Pedal functions or play MIDI Notes or a Sample, has 2 separate MIDI Output Ports and 2 MIDI inputs (merge), has built in EQ and Auxiliary Audio (stereo) I/O Mix, Controls the VLT2 via MIDI CC's, Special Notes, and voltage inputs....

OK enough! I will be making some videos in any case and I will post then here

Cheers, and thanks for putting up with me! S*