Let's design a tap tempo tremolo.

[flo]

Thanks for the BOM! 

[caress]

can taylor, electric druid, jkowalski or anyone else recommend some good reading for microcontroller programming?  especially as related to audio and/or control signals?

also, any programming software or hardware interface suggestions?  any for mac?

[Taylor]

I don't really know much about microcontrollers, but have you seen this (from the Digital & DSP section of this site)?

http://www.diystompboxes.com/smfforum/index.php?topic=42476.0

I can offer a decent amount of help with the FV-1 DSP chip, but if you're wanting to do digital control of analog signals like this trem project, I probably know about as much as you do about it.

[caress]

thanks taylor, there's plenty there to start with.
it would be rad if someone who programmed one of these PICs could lend a hand!  i'm interested in the process...

[Taylor]

Ok, the build PDF is done, have a look:

http://www.aronnelson.com/gallery/main.php/v/Taylor/

Any comments on things that are unclear, wrong, misspelled, etc. are welcome.

[jkokura]

Great work Taylor.

One question. Electric Druid's diagrams and .pdf order the wave forms in a different order than you described. It would be helpful to know precisely the order of the wave forms - especially which way they go. Does it progress clockwise from '0' to '10' on the pot from 'a' through b, c, d, e, f, g and h, waveforms, or from '10' to '0'... I might be the only one confused, but if I were to make my graphics and then fire up the pedal and find out the waveform knob doesn't match the graphics... I guess I'm asking you to make it really, stupidly, obviously easy to understand that function.

Thanks bud, you've done a super awesome job on this one, and I think it's gonna be a fabulous build! I got two boards after all, and I'm willing to get more to make for other guitarists if they're interested.

Jacob

[Taylor]

Looking at the documents, I'm pretty sure what I wrote matches Tom's documents and picture of the waveforms (one exception I just noticed is that I forgot to mention the random step waveform, which is included).

It may be confusing because I called some of the waves by different names.

Hypertriangle=sweep
inverted hypertriangle=lumps

So, from 7-o'clock on the dial, moving clockwise to 5-o'clock on the dial, the waveforms are

up ramp
down ramp
pulse
triangle
sine
hypertriangle (sweep)
inverted hypertriangle (lumps)
random

Can you point me to where I have it written differently, I can't find a spot where it's different? I know the formatting is a little hard to read; all my formatting was lost when converting to PDF - though I'm not a total idiot and have the full Adobe suite, I still can't figure out how to really work with PDFs. I'll hopefully fix this in the coming days, but I'm swamped right now and just wanted to make sure the info was there.

[jkokura]

The different names and leaving out the last one was I guess the differences. A closer look puts them in the right order, but I guess I thought the Lump and sweep were the first in the list. The clearer description you just gave helps a lot though, and not just me I hope.

Jacob

[JKowalski]

http://www.mstracey.btinternet.co.uk/pictutorial/picmain.htm

That one was the first tutorial I read and it really helped me get the basics down. From there, I kept learning by looking up functions that I find and don't understand, analyzing snippets of code that other people have written to do specific things and figuring out what makes them tick, going through completed code and analyzing the program as a whole, and the odd specific tutorial.

I found that once you know how everything works in a very basic sense you can easily learn ASM by simply building on your knowledge through experience. Analyzing someone else's code is a great way because you get introduced to functions you have never used before quite often, and rather then simply learning functions you can learn how a program is put together to make it streamlined and efficient.

I find that coding ASM is less of a cut and paste kind of deal, and more of a logic problem. You have limited functionality in the language, so to solve complex problems you have to use the language in creative ways.


Buying a programmer is well worth the money, don't be hesitant on that if you really want to learn code. Mine was a USB powered, serial port data programmer for only ~$14 and that has served me very well.





And remember if you want to reverse the order of the waveforms just reverse pins 1 & 3 on the pot 

[svstee]

Does anyone have soundclips of this? I'm about to order the PCB, but I'm still a bit on the fence.

[Taylor]

I doubt it. I think JKowalski, .Mike and I are the only ones who have built them so far, and I don't know about the other guys but I don't really have a recording setup right now.

However, I will refund the price of the board to the first person who builds one and records sound clips.

[.Mike]

Does anyone have soundclips of this? I'm about to order the PCB, but I'm still a bit on the fence.

I posted some sound clips when I built the original tremolo based on the chip from which the tap tempo chip evolved, and from which the schematic for the tap tempo tremolo evolved. As far as I am aware the wave shapes are identical between the two chips. The circuit is also practically identical to the tap tempo tremolo circuit-- my original version just doesn't have the tap features.

The audio path is practically identical to that of the Tremulus Lune except that I used film caps for the input and output caps instead of electrolytic. If you like how that sounds, you will like this. The only difference is the LFO (and it is a big difference due to the flexibility of the PIC LFO), and of course the tap feature.

Anyway, here is my original topic with some sound clips, along with visual representations of the waveforms and wave distort feature: http://www.diystompboxes.com/smfforum/index.php?topic=77471.0

I don't remember if the clips are any good, so take them with a grain of salt. Still, I hope that helps you decide, and I hope you decide to get one.

Mike

[NQbass7]

Does anyone have any input on potentially using rotary switches for waveshape and multiplier?  I'm thinking use a 1P8T (e.g. for waveshape, 1P6T for multiplier)) with maybe 1k resistors between each throw, and then connect the first and last throws to the outside lugs of the pot connections, and the pole of the rotary switch to the middle lug.  Would that work?  It looks like it's just a voltage divider, so I think that would work...  The only thing I'm concerned about is where the ranges actually fall, and if I'd be riding the line between voltages the chip is looking for rather than landing in the middle of the range.  I might need a 470ohm on the end to make the voltage fall in the middle of the range, I'm not sure.  And I don't think it'd be a problem for it to be less than 10k total resistance, but I could always choose resistor values that put it there if needed.

I was thinking this switch: http://www.smallbearelec.com/Detail.bok?no=477

Any thoughts?

[Taylor]

Tom has directions for that in his datasheet:

http://electricdruid.net/datasheets/TAPLFO2Datasheet.pdf

[NQbass7]

Doh!  Thanks for pointing that out.  Apparently I stopped reading the datasheet before I got to that point...

[Taylor]

For those building the project, I've started a thread for questions about building it, build reports, etc.

http://www.diystompboxes.com/smfforum/index.php?topic=84020.0

[Fuzz Aldryn]

Hi,

made my own tap tempo tremolo inspired of course by the things which have come up here.

It's fully working and nearly total smd.

http://www.youtube.com/watch?v=wmI9JOuNjQU

Cheers

[Taylor]

Very nice, would love to see the trace side of the board if you don't mind sharing it. Which control did you leave off?

[aziltz]

has anyone suggested using this new TAPLFO thing to do phaser, wah, and other mods?

[Taylor]

Do you mean, has anyone come up with a schematic for one of these? AFAIK no. The reason tremolo was so easy is that the output of the TAPLFO puts out a PWM signal, which needs to be filtered before it can be used as an LFO. The optical tremolo is slick because the LDR simultaneously accomplishes the filtering (by way of its slow response) and the actual amplitude modulation. So to do one of these other effects you'd need to deal with that in a different way. A PWM phaser would be quite possible, I believe Nelson did one awhile ago.

The other thing is that tap tempo has diminishing appeal for some other effects to many people, myself included. Rhythmic delay and tremolo make sense with the way most people use these effects. But personally, for phaser/flanger/filter type stuff, I like slow sweeps that aren't tied to the tempo of the music.