Flo Rida Optical tap tempo Tremolo

[Kipper4]

Right Ben N
I've looked into some more mods and am now able to set the minimum rate of the lfo so it can be set.
The lfo rate rises sharply on playing notes and chords and decays at a rate set by the decay pot in the charge pump envelope detector.
Notice a few changes No more bjt detector. it's all op amps now, less parts.
The manual/enveloped switching has changed this is how i maintain a min rate.
Probably not the most elegant of designs but it works well and with a tap tempo tremolo thrown in with 8 different wave forms, seems like a no brainer.
Rich

[Kipper4]

I should maybe add a 5V2 Zener diode clamp  before on pin6
Probably series 1k >Zener in reverse bias to gnd

--------/\/\/\------/-------- pin 6
             1k          /
                          /
                         /\
                       -----
                          /
                          /
                          /
                       -----
                        ---
                         -

Like it? 

[Kipper4]

I should point out that although the data sheet for the Stomplfo stipulates a max +5v on most pins.
This chip is very robust I know from the DMM that the op amp led driver has thrown out as much as +8V.
Note I also swapped the previous versions envelope and drivers LM358 for the ubiquitous TL072.

I might be about to jinx this but I haven't killed one yet.

I'm in too minds to do an lfo automated sweller with it for fun of it.
I have too much time on my hands.

[Ben N]

Thanks, Rich. Cool project. I had been thinking a bit about the VFE Old School, which has nice envelope options (amplitude and speed), but no tap tempo, and how to integrate one of Tom's chips into it. But it is transistor based, not optical, which I think would make this harder to execute. Your approach seems right on the money, and still not overly complicated.

[Kipper4]

https://youtu.be/edFz7PC4_AY

[Nicotep]

That's making me think of stereo phasers with one channel running opposite phase to the other. Or a panning trem. Hummm....

T.

Tom, I was gonna write you a mail about this idea, then I thought I'm probably not the only one interested in it.
How to reverse the phase of the PDM out? So we could both drive one volume (aka output) with the PDM and another one with its opposite?

[ElectricDruid]

That's making me think of stereo phasers with one channel running opposite phase to the other. Or a panning trem. Hummm....

T.

Tom, I was gonna write you a mail about this idea, then I thought I'm probably not the only one interested in it.
How to reverse the phase of the PDM out? So we could both drive one volume (aka output) with the PDM and another one with its opposite?

There's quite a few options. Since it's a digital output, a simple digital inverter will do the job. That's one way. Another option, if you're running something like vactrols from it, is to wire up one from the +5V rail down to the output, and the other from the output to ground. Like that, one's on when the other is off and vice versa.
Finally, you've got *actual analogue* solutions, like filter the output to get an LFO waveform, then stick it through an inverting op-amp buffer. That's probably my least favourite way since it uses the most parts.

[Nicotep]

There's quite a few options. Since it's a digital output, a simple digital inverter will do the job. That's one way. Another option, if you're running something like vactrols from it, is to wire up one from the +5V rail down to the output, and the other from the output to ground. Like that, one's on when the other is off and vice versa.
Finally, you've got *actual analogue* solutions, like filter the output to get an LFO waveform, then stick it through an inverting op-amp buffer. That's probably my least favourite way since it uses the most parts.

I didn't even know vactrols could be used both ways (ok, never used one actually, always used cheap homemade LED+LDR combos). Sounds like the easiest solution... And it prevents me from asking you how to use a digital inverter.
Thanks

[Kipper4]

Let me know if you build it.
DuckArse has already done the opposing leds vibrato.
I'll see f I can find a link but it's a bit more complex a build than this.
Good luck
Rich
I'll help as much as possible should you have debugging issues.

[ElectricDruid]

I didn't even know vactrols could be used both ways (ok, never used one actually, always used cheap homemade LED+LDR combos). Sounds like the easiest solution...

It's just a question of voltage across the LED, and that means any LED, in a vactrol, in your homemade LED+LDR, whatever. When the output is high, the LED from 5V to the output (also 5V) has no voltage across it, so doesn't light. But the one from the output (5V) to ground does. When the output is low (0V), the LED from 5V to the output now has 5V across it so it lights up, but the one to ground is wired from 0V to 0V so does nothing.

And it prevents me from asking you how to use a digital inverter.

Something like the 74HC14 (or any of the previous versions of the same chip). You put a logic level (So 5V or 0V) in and you get the opposite logic level out (so 0V or 5V). Dead simple.

https://assets.nexperia.com/documents/data-sheet/74HC_HCT14.pdf

HTH,
Tom

[Boba7]

Another option, if you're running something like vactrols from it, is to wire up one from the +5V rail down to the output, and the other from the output to ground. Like that, one's on when the other is off and vice versa.

Hey, I was just thinking of connecting two vactrols that way to the Stomplfo, so it's great to read it should work!
But if I wanted to add an LFO led, do you think I could simply add a parallel one (with its own resistor of course) from pin3 to ground (or 5V to pin3), or should I use a simple transistor switch like this? Or would it be even better to use a transistor for each led? (including a PNP switch then, to have the two vactrols out of phase)

Thanks a lot!

[ElectricDruid]

I'd certainly try the simple parallel way first. If it works (and I'd expect it should) then bingo! No problem!

If not, you've always go the transistor buffered way to fall back on.

T.

[Boba7]

I'd certainly try the simple parallel way first. If it works (and I'd expect it should) then bingo! No problem!

If not, you've always go the transistor buffered way to fall back on.

T.

Thanks a lot, I didn't expect such a fast answer!

[Bitinwood]

Heres an updated enveloped tremolo.

Hello kipper4, I'm quite interested by your schematic, but I'm confused with the vb on the power supply, cause there is no vb on the schematic, is there the supply for the op amp ? Thanks in advance

[antonis]

I would like to see a TL072 working at +2.5V single supply..

[bluebunny]

there is no vb on the schematic

Find the "x" in the "Trikbox" title and travel north a short distance (it comes off the regulator).

Edit: having said that, I can't see where it's used.  Rich has another divider to make VB for the opamp.

[Bitinwood]

I would like to see a TL072 working at +2.5V single supply..

It have 2.5von the negative input, and the voltage divider is 5v>10k ^vb > 22k >ground, so bb is around 3.75v that why look a bit strange to me 😊

[Kipper4]

Can't remember why I put Vb in there.
I can tell you this though. it worked on the breadboard.
Have fun building it and let us know how it goes please. Following.