A different approach to a tap-tempo Hamlet Delay

[solderfumes]

I posted about this before it was boxed, but the thread got wiped when the server problems struck.  I wanted to try my hand at Jon Patton's Hamlet Delay because his demos sound great and the circuit looked nice, simple, and elegant, but with some added bells and whistles: tap tempo, two PT2399s for extra delay, and an effects loop.  I bought a Taptation chip for the tap tempo, but when I did a little more research into how it works, I found that it isn't an ideal situation if you wanted to double up on the PT2399s.  A little more digging through forums revealed several helpful posts (particularly this one http://www.diystompboxes.com/smfforum/index.php?topic=94484.30) suggesting that a PLL would be a good way to get two PT2399s to sync without heterodyning.  There were also suggestions that this approach could be used to implement the tap tempo as well.

I then decided to finally try my hand at some Arduino programming, and after a bit of trying to get the uC to work as a tap-tempo oscillator and PLL, decided that it wasn't going to be fast enough to do both, so I programmed it to be a straight tap-tempo oscillator and turned to a CD4046 for the PLL duties.  This was fun!  I studied computer science but had never made anything that actually controls a real world machine -- closest thing I'd ever done was make two computers talk to each other, and that's kind of cheating )

Anyway, this is what I ended up with:

IMG_2574 by dickolaswang, on Flickr

IMG_2573 by dickolaswang, on Flickr

and this is how it looks in context:

IMG_2613 by dickolaswang, on Flickr

IMG_2612 by dickolaswang, on Flickr

(My middle name is Hwa.)

I learned a lot from Rod Elliott's page too (http://sound.westhost.com/project26a.htm).  The secondary PT2399 stage is based on his Super-Simple PT2399 Delay Circuit, figure 3 on that page.  I tried to go light on the filtering on that stage, as I thought the filtering on the primary stage would handle the noise (the secondary stage actually precedes the primary one).  It almost does, but when the secondary PT2399 is engaged it definitely sounds a little gritty/distorted.  I should try a different PT2399 in that spot to see if it helps, but I can live with it, and I probably won't need the extra delay time much anyway.

I had a few issues putting it together: I fried one of the switches so it had to be replaced (which is a mean feat without desoldering braid, which I bought and promptly lost).  One of the pots was bad, too, so it had to go.  In replacing both of those things, I broke another trace on the board -- to go with the one I broke originally assembling the board -- so there are two ugly white jumpers on the finished product.  I also made a mistake on the board. I grounded pin 5 on the uC because I didn't fully understand the datasheet and thought it was an input pin.  Turns out that it can be an input if you futz around with the firmware, but by default it's a reset pin.  Next time I build it I will cut the appropriate trace, but in the meantime I lifted the pin by fashioning a 7-pin socket out of SIP sockets.

Nonetheless, it now works, and I'm still kind of blown away that I managed to get this project finished and functional!  Still gotta work on those EnviroTex and painting skills

[playpunk]

Woah!!


Sent from my iPhone using Tapatalk

[Martan]

Woah!!

Indeed

[monkeyssj1]

Dude this is rad. Congrats!

[Kunfuz]

Excellent and inspiring build, thanks for sharing!!

[Matt]

That's wild. Very nice build!

[Jebus]

Very nice! Its nice to see some uC implementations on pedals. I've been tinkering with Arduino and tap tempo for some time now. Basic idea that I have is to have a LCD-display that shows tempo and maybe some additional information and rotary encoder so you can adjust the tap tempo on the fly.

[midwayfair]

Great job bending the machines to your will! And thanks for the detailed report on bringing it to fruition! Very much something to be proud of.

[287m]

hat off for you, 2 thumbsup
(y) (y)

[lincolnic]

Now that's some fine engineering.

Also, can we talk about how your Flickr username is Dickolas Wang for a minute. Do you have a secret career in film you'd like to tell us about? 

[alparent]

So the Arduino sketch and schematic will be posted soon? 
Would really like to use my Arduino to do more then flash LEDs!

[Coda-effects]

This really impressive!
I had a similar project in mind with a double delay, but I am not able to code such complex (well, for a beginner like me ^^) yet.

We want clips!

[solderfumes]

Thanks everyone for your kind words

Very nice! Its nice to see some uC implementations on pedals. I've been tinkering with Arduino and tap tempo for some time now. Basic idea that I have is to have a LCD-display that shows tempo and maybe some additional information and rotary encoder so you can adjust the tap tempo on the fly.

Yeah that would be awesome.  I didn't have enough IO pins on the ATtiny to try anything like that, and I was concerned about the amount of time it would take to perform the analogue read on a delay pot, but I'm quite sure if you went with a more powerful uC that would be no sweat

Also, can we talk about how your Flickr username is Dickolas Wang for a minute. Do you have a secret career in film you'd like to tell us about? 

Haha, I haven't really gone by that in a few years now (you know, since I joined the workforce), but that's when I signed up for the Yahoo/Flickr account.  No film career, just a slightly unfortunate first name and some university buddies who, in retrospect, were mildly racist.  Eventually I decided to get out in front of the message.  Until Google Photos makes it easier to embed pictures, I guess D to the W rides again.

So the Arduino sketch and schematic will be posted soon? 
Would really like to use my Arduino to do more then flash LEDs!

Here you go:

https://drive.google.com/folderview?id=0B8Qn1G0R3IKVNWZwVkFOUFhReHc&usp=sharing

I also have four more boards that I'm probably not gonna use... hint hint

We want clips!

I don't really know the first thing about video editing, but if I remember I'll ask my friend to help me throw something together.  Overall though it basically sounds like a Hamlet Delay, so check out Jon's demo videos.  There is a bit more cold digital noise when the tap-tempo is engaged, but nothing serious, and it sounds a little noisier/distorted when both PT2399s are engaged.

[alparent]

I also have four more boards that I'm probably not gonna use... hint hint

Sending you a PM..... hint hint

PS. Let me know if you got the PM. I've sent PM's lattely with no response. Not sure if people or not getting them or just ignoring me

[solderfumes]

Yep just replied.  Let me know if you didn't get the message!

Also I should mention that though I wrote the code in Arduino, I was really only using the Arduino platform itself to program the ATtiny chip, following these instructions: http://highlowtech.org/?p=1695

Another thing I forgot to mention above is that there's another annoying bug on the board: the diode footprints all came out in the opposite orientation to how they're supposed to be.  I think I must have designed the board right after upgrading KiCad, and a bunch of footprints got garbled -- only noticed after I put the thing together