PHOBoS' Modular Lunetta

PHOBoS

copied from other thread

PHOBoS · Last edited by PHOBoS on Sun Oct 21, 2012 1:30 pm; edited 2 times in total

The power module

There's not a whole lot to say about this module: a DC input connector, protection diode, on/off switch
with indicator LED, a big 4700uF capacitor and a couple of 'outputs' incl 2 banana connectors.

I choose a nice fat diode [1N5408] rated for 3 amps. An 1N400x diode would probably be sufficient,
but with the 4700uF cap and all the decoupling caps on the modules the inrush current might just be too much,
and I had one laying around anyway.

The reason I wired the switch they way I did (shorted on one side) is only because it was more practical to
solder it this way. I had thought about putting the 4700uF capacitor before the switch, but it was much easier
to place it parallel to the outputs, and as a bonus I get a powerstarve effect when I turn it off.

There's no voltage regulator, so the system just runs on whatever I supply it with.

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PHOBoS · Last edited by PHOBoS on Sun Oct 21, 2012 1:49 pm; edited 1 time in total

4040 divider

This is also a very basic module: a simple transistor inverter for the CLK input, and a reset switch + ext reset input
seperated by a simple 2 diode/resistor OR. (The diode connected to the switch isn't actually necessary, but I wasn't
100% sure yet how I was gonna connect it when I soldered the board so I put it in just in case Wink

).

all the outputs have a LED with a 4K7 series resistor which makes the LED's light up bright enough without
drawing too much current, since at some stage 12 LED's light up and the current could be too much for the chip
to handle if the resistors are too low. The LED's are just basic 3mm diffused.

I put a 1K current limiting resistor in series with the outputs and a diode so I can clip multiple outputs
together on one input. Cool

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PHOBoS · Last edited by PHOBoS on Fri Dec 21, 2018 11:36 am; edited 9 times in total

Flame-LED Oscillators

something you probably won't see in most lunetta's, at least up untill now Laughing

tea-candle LED"s are curious things, once you listen to them that is Shocked

. Some sound like a series of beeps
available in a range of frequencies, and others play actual melodies. I think those are mostly the older ones,
when it was easier/cheaper to take an existing chip, and I guess they where probably made with a seperate PCB at first.

The sounds they make are actually just a series of bits (PWM ?), which is offcourse perfect for use in a lunetta.
You only need to make it usefull somehow which is quite easy.
just connect a schmitt trigger gate to the point between the LED and series resistor and you get a nice bitstream.
And with the addition of an extra transistor it can also be turned on remotely.

the resistors/diode/LED on the ouputs are the same as the 4040 divider and I plan to do this for all the outputs on
modules.

I selected 4 LED's, by listening to them, ranging in frequency. 2 are in the same range, but higher then the other pair
which are also in the same range. No 'real' melodies used in this one.

I soldered the LED's to the back of the front facing outwards, so they shine through the perfboard.
yes, I have a digital fireplace in my lunetta. Twisted Evil

edit: added some demo sounds:
- first demo is just the seperate outputs, from low to high
- second demo is the result of chaining them output to gate in from low to high. sound from the last LED.

edit: uploaded video to the forum since it is no longer available on youtube.

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PHOBoS - Flame-LED Oscillators demo (Okt 21, 2012).mp3

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seperate outputs, one by one

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PHOBoS - Flame-LED Oscillators demo2 (Okt 21, 2012).mp3

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chained

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lunetta fireplace.wmv

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lunetta fireplace.wmv

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PHOBoS · Last edited by PHOBoS on Tue Oct 23, 2012 4:07 pm; edited 2 times in total

Triple R/2R Network

There's a little bit more to this one then just a bunch of resistors, but not a whole lot. Because I choose to put diodes
on all the outputs I can't just connect them directly to an R/2R. So I added some non-inverting buffers in the form
of a CD4050, which as it just turned out, will solve another problem too. With 6 buffers for every chip I could make 3
4-bit R2R's with 2 chips, which was also just right for the available panel space.

the output is buffered with an opamp wired as a voltage follower, but as I allready suspected, it clips when
all 4 inputs are high.I came up with 2 ways of solving this (or actually 3):
Adding a voltage divider between the R/2R and the opamp, but I'm not exactly sure how that will
effect it's behaviour, or power the opamp from a higher voltage/cmos from a lower voltage.

It is possible to increase the supply voltage for the opamp with a small circuit, but it's much easier to power
the CMOS chip from a lower voltage. but you have to be carefull there,. you can't just attach the input
of a 5V powered chip to the output of a 9V powered chip, so that would require a voltage divider on the input.
one extra resistor would be enough since there is allready the pulldown resistor. but I remembered reading
something in the datasheet about using the 4049/4050 for level conversion between CMOS and TTL.
I just looked it up and, I quote:

PHOBoS · Posted: Sun Oct 21, 2012 4:56 pm Post subject:

one thing I want to mention about the previous modules, I'm currently low on 100K resistors so I used 47k instead but
of course you can use whatever you're used to. I had just ordered 50x 100K resistors (which i think are 0.1%, not the 1% I ordered Laughing

)
but I allready used 36 of those in the triple R2R Shocked

what's next:

I have a couple of ideas in my head, so might as well write them down here and see what else I come up
with on the spot

ok let's see:
oscillators! i gotta have those, probably some gated 4093 based ones with a range switch. maybe two outputs:
one inverted. I could make 2 of those with 1 CD4093, which would probably fit nicely on 1 panel if i use alpha pots.
or maybe I can make a slightly larger panel with 4 oscillators. I have to make some different sized panels anyway
to fill the whole front.
babble

finished 2 oscillators

Maybe some simple non gated 40106 oscillators,. with remote power control and a starve function.
A starve function is something I have thought about making into a seperate module, but I'm not
sure there are many chips that actually benefit from this, so it might be better to incoroprate it with the oscillators.

Logic gates (AND/NAND/NOR/XOR): I will probably make a dedicated panel for some XOR's, but something
else I have in mind is an X-gate panel (not to be confused with the any-gate Wink

). This will be a panel with
a 14 pin socket on the front panel, so I can put in different chips which have the same pin layout.
babble

finished X-Gate module

A variation on this is an X-chip panel, which will just have all pins wired to the front, with pulldown resitors
on all pins (maybe larger then usual) and the socket mounted on the front aswell. Maybe I can come up with
a way to incorporate LED's too.

a CD4017 counter module, for non binary divisions among other things
babble

finished

hmm now that I say counter, a module with a LED display would look great. Doesn't even
have to be hooked up to display numbers, so I have to think about what module I'm gonna attach that too.
[I also want to make a visualizer module with a matrix LED display someday, probably incl a PIC for different
modes. But I don't think that will end up in this lunetta. we'll see Wink

]

another thing I have to add with a CD4017 is the 4017/4051 melody generator.
I experimented with this little ciruit before, with some very nice results.
For those tests I made a small PCB so I only have to make a front and wire it up. Very Happy

another one of those circuits I did a bunch of experiments with is Cynosure's CMOS waveshaper.
I also have the 4015 version of that one allready soldered up,. so I might use it for a module aswell:
Posted Image, might have been reduced in size. Click Image to view fullscreen.

however, after those experiments I came up with an extended version which has a bunch of switches.
and a lot of extra options. It would be great to make that one, afterall I did design it for a modular lunetta system.
But I have to see how much panel space it would take up first.

put LED display(s) on that one (which I mentioned somewhere in that thread too i think)

back after the break,..

PHOBoS · Posted: Sun Oct 21, 2012 5:43 pm Post subject:

VCO's, at least 2
I did some experiments with a simple 4046 VCO which sounds promising.
posted below is a short demo using it with the 4040 divider and R/2R. (in which you can also hear the clipping;
it can't reach the highest note). I will have to add the voltage regulator first before i do more experiments.
It's probably gonna have a glide pot, I like the sound it makes at short settings Very Happy

, and several in/outputs
so I can make more use of the chip.
babble

finished 2 VCO's

an (output)mixer. It's nice that it can make sounds but even nicer if you can actually hear them,
and have some control over the levels. because I put diodes on the outputs I can allready mix outputs together
that way. But I also want a mixer with some pots for both analog and digital signals. Not sure how many channels,
can't make it too big. I saw tjookum used some small slidepots that might be nice. I'm probably gonna use two cinch
connectors for the outputs. I'm not sure if I'm gonna add some sort of CMOS filter, I think I'd rather use the space
in this case for some more digital logic.
babble

finished a dual output mixer

An interface for external signals: Comparators with protection diodes for the inputs, and maybe some
attenuators for the ouputs. I could make a panel with a Sub-D connector on it, and a seperate box with some jacks
and the actuall circuitry. This could also be used for an interface with a joystick, some switches, maybe something
with LDR's,.. Laughing

made a 16 I/O interface module.

Shift register I have to look into what chip I'll use for this. Probably a CD4015.
babble

finished a 4015 shiftregister module (2x4/1x8)

CD4520 dual 4-bit binary counter instead of another 4040 divider panel, and it can be linked for 8 bit Very Happy

made a CD4029 counter module instead.

I also have a couple of CMOS chips I ordered a while back, types I haven't used before, I think the 4089
was one of them, but I'm not sure what the rest is, so will look up what I have.

I have some more ideas but I think that's it for now Cool

recommendations are welcome!

PHOBoS - R2R VCO demo (Okt 21, 2012).mp3

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tjookum · Posted: Mon Oct 22, 2012 2:19 am Post subject:

perf porn!

bubzy · Posted: Mon Oct 22, 2012 2:20 am Post subject:

love that fireplace!!! Very Happy

PHOBoS · Posted: Mon Oct 22, 2012 3:17 am Post subject:

RingMad · Posted: Mon Oct 22, 2012 2:12 pm Post subject:

Thanks for sharing this treasure trove of information, PHoBoS! Following your build is inspiring and the results will no doubt be yet another thing of beauty. With fireplace.

I have some older tea-candles LEDs and they have the black blob. Newer ones don't... it's just magic. But I never thought of listening to them (except via photo-resistors going into my non-Lunetta Triowaverator box).

James.

PHOBoS · Posted: Tue Oct 23, 2012 2:04 pm Post subject:

PHOBoS · PHOBoS - R2R VCO demo (Oct 23, 2012).mp3

I said I was going to add a 78L05 to the triple R2R module to power the CD4050's and so I did.
As expected, no more clipping at the top level, and at first everything looked to be working perfect. Razz

you can skip this part if you like, it's the experimentation which led to choosing a different opamp in the R2R

So I continued experimenting with the 4046 VCO, and I noticed that the lowest levels didn't have any effect on
the pitch. I presumed that the CD4046 probably needs a minimum input voltage, so instead of the R2R, I
hooked up a pot as voltage divider and this confirmed what I was thinking, somewhere from 0.8/0.9 V the
voltage started to effect the pitch.

All that was needed to do now was add an offset voltage to the input. My first thought was opamps, but didn't want
to go that route right away, especially with a single supply. So I tried adding pullup resistors and some transistor
configurations, but eventually did grab an opamp. Wink

So that should be pretty easy, right ?, I breadboarded a basic inverting summing amp (47K resistors) with
an extra offset pot, with it's ouput connected to another inverting opamp. (else the pitch would go down
when the voltage goes up). Both opamps connected to a virtual GND point. (opamp used: LM324).

I was still using the potentiometer instead of the R2R and sofar this was working fine, by adding the offset
voltage it now worked from 0V up. Very Happy

I connected it to the R2R and Shocked

no matter what offset voltage I supplied there was no different in pitch
in the lowest voltage levels. (R2R inputs: 0000/0001/0010/0011 all sounded the same)

hmm, I hooked up my scope to the ouput of the R2R, and that's when I saw that it wasn't just the VCO
not responding, the output from my R2R wasn't changing either.

Since the levels straight from the R2R before the buffer seem to be fine it got me thinking that maybe the input voltage
for the opamp was too low (allthough I seem to recall an LM324 pretty much working from 0V up on a single supply).
The last thing I tried before going to bed last night was a 1M pullup to the input of the buffers and this seem to solve it.

sleeping

allthough a resistor seem to solve it I wasn't done experimenting yet.
Next thing I tried was using a TL074 opamp as a buffer to see what the effect was, but this only made it worse.
With no inputs I got an output of a few volts, then it would go down in steps and then back up. Confused

I noticed that on my breadboard (where I attached the R2R output to the inverting summing amp) some resistors
might have been touching causing this effect, I took that part off so it was just the scope directly attached to the
output of the R2R, but still the same down/up effect. I didn't really expected the TL074 to do better on a
single supply anyway so back in with the LM324.

powered it back up and

it suddenly worked perfect !

wait a minute! thinking

, could it be,.. nah really ?!
I hooked it back up to the summing opamp and yep,. no pitch change on the first bits, so somehow attaching the ouput
to the opamp caused it. I changed that opamp too just to be sure but that wasn't it.

As it turns out, the LM324 can hardly sink at low ouput levels, from the datasheet I got 50uA at 0.2V out with
a 15V supply voltage (I'm using only 9V). Since the non inverting input of the summing amp is attached at 1/2Vcc
the inverting input is at the same level, and the LM324 just doesn't have enough juice to pull it down Wink

. Using very
large resistors in the Mohm range instead of the 47k might work. but then I still have the same problem if I would
attach it to something else. Solution: a different buffer opamp.

I just happened to have 1 TS274CN (no idea why I have it). And that one seems to work perfect Very Happy

some info from the datasheet for what it's worth:

bubzy · Posted: Wed Oct 24, 2012 5:00 am Post subject:

and i thought i built fast Very Happy

PHOBoS · Last edited by PHOBoS on Thu Oct 24, 2019 6:44 am; edited 5 times in total

PHOBoS · Posted: Fri Oct 26, 2012 10:57 am Post subject:

some more ideas:

of course a mux or muxes 4051/4052

some flip flops might be fun, 4043/4044

ok let's see which 'odd' chips I have here:
40174 - Hex D-type flip-flop with reset; positive-edge trigger.
Very Happy

maybe I use that instead 4043/4044, have to check the datasheet
and so I did. 6 flip flops with a common clock and reset. Usefull and very easy to make a panel for,
but I want some independent flip flops first. so 4043 is the one Cool

finished 4043 module

4521 - 24-stage frequency divider
hmm could be interesting,. have to look up what that's about.
it has an internal oscillator (RC or crystal) but looks like it can take an external clock aswell.
so it can be used like a 4040 divider but outputs are Q18-Q24. Q24 = divided by 16.777.216 !

4560 - NBCD adder
a math chip,. those are fun Wink

. will do some tests but can probably just wire it to the panel completely
babble

finished

4572 - Hex gate : quad NOT, single NAND, single NOR
ah yes,. the weird one, I wonder who came up with that ? the platypus amongst CMOS chips.
Posted Image, might have been reduced in size. Click Image to view fullscreen.

(damn you brain,. now I want to build a module with a platypus on it Confused

)

4026 - BCD counter with decoded 7-segment output
hmm,. I allready said I wanted a 7 segment display Razz

edit: just looked it up. it's indeed a counter with a display driver but doesn't look very usefull.
It has a clock and reset in, display outputs and a carry out. Maybe usefull in combination with another chip.

4073 - Triple 3-input AND gate
maybe If I have some panel space left.

4078 - 8-input NOR gate
don't think I need that one.

I will have to look up some more information in the datasheets before I decide further.

analog_backlash · Posted: Fri Oct 26, 2012 3:46 pm Post subject:

Love the demos PHOBoS, especially the R/2R bits. I too used the 4050 chip on my randomizer circuit R/2R - I thought I was being original there, but it's probably all been done before. I've come to the conclusion that I also want to add an 8-bit R/2R across my sequencer, as it seems too good an opportunity to miss (the trouble is, I never finish anything this way).

Keep up the good work,

Gary

P.S. I had to download the 4572 datasheet, to believe it was true - what were they thinking? The platypuses (platypi?) are so cute though.

PHOBoS · Posted: Fri Oct 26, 2012 4:01 pm Post subject:

analog_backlash · Posted: Fri Oct 26, 2012 4:28 pm Post subject:

Just been modding my mixer and it works a lot better now (thanks again for your help on that). I'll try breadboarding an 8-bit R/2R tomorrow (probably) and see how it sounds. It's not too critical in this application as I haven't got a 1V/octave VCO or anything like that. If I want to adapt it for my conventionally tuned synths, that would be different (I'd probably use a DAC chip of some kind). Anyway, the beauty of breadboarding is that if it's lousy, you can adapt it (or give up if it's that bad).

And yes, I do want to pet them, but watch out for the venomous spurs... Twisted Evil

ENGAGE BRAIN BEFORE POSTING!

Realised after posting that the R-2R which I was going to add will be 3 or 4-bit one from the outputs of the 4029 in my sequencer. I was thinking 8-bit because it's an 8-step sequencer Embarassed

I just wanted to add the possibility of a staircase waveform, which currently I do not have.

Skrog Productions · Posted: Tue Oct 30, 2012 11:04 am Post subject:

nice looking modules , that case will fill up quick Smile

Dave.

PHOBoS · Modular Lunetta - Oct 31, 2012

elmegil · Posted: Wed Oct 31, 2012 8:26 am Post subject:

Do you do anything but work on this? Very Happy

I'm burning midnight oil trying to get a single Soundlab built and ready for someone, and you're running rings around with your Lunettas Smile

PHOBoS · Posted: Wed Oct 31, 2012 8:30 am Post subject:

PHOBoS

I added a decent power rail with 18 cinch connectors, which is the maximum of modules I can fit in.

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PHOBoS

I also made 3 new modules, first:

4093 Gated Oscillators

a schmitt trigger NAND gate configured as a gated oscillator with a range switch to use it for audio or an LFO.
Because the output of the oscillator is high when turned off (gate in low) there's also an extra NAND added
to invert the signal.

I might make another one of these but I also want to make a starved oscillator. So it depends how much room I have left.

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