Turkey Day SHOOTOUT Competition

[pakrat]

Ummmm.... THOSE builds 

[samhay]

Wow - they just keep coming.
I got the circuit built last night - it worked first time, which was rather lucky as I didn't have time to breadboard all of it. No convenient holiday in the UK to get it finished, but I may still have to cram it into the enclosure tonight - family willing.

[deadastronaut]

@sam: tick tock tick tock.....no pressure!!!..

[Mustachio]

Forgot to mention Gord, I love those connectors on your board. Nice touch!

[pakrat]

Jim, great playing in your vid

[digi2t]

Jim, thanks for the big fat guitar lesson. I could listen to you all day long man. Nice!

[pinkjimiphoton]

wow, every time i think my minds made up, it gets re-blown.

you guys are absolutely outstanding. it is an honor i don't think i'm worthy of to be asked to judge such fine examples of the diy ethic,
you guys @#$%ing rock. period. sorry... it had to be said.

time is ticking away... i HATE to see anyone run out of time to enter. but the rules are the rules.

thanks to EVERYONE.

[GGBB]

I could listen to you all day long man. Nice!

Yep - same here.

[haveyouseenhim]

Wow, it's 1:10pm and I just woke up to two new daggers in my hopes of even placing in this comp.

Two really great builds guys!

@daggum drug stoner         Is that pour on clear coat?   Whatever it is, it's beautiful!

[digi2t]

@daggum drug stoner         Is that pour on clear coat?   Whatever it is, it's beautiful!

That's got to be 100% acrylic urethane love man!

[haveyouseenhim]

@daggum drug stoner         Is that pour on clear coat?   Whatever it is, it's beautiful!

That's got to be 100% acrylic urethane love man!

Derp     I just re-read Jim's post and it is pour on clearcoat

[Mustachio]

Aww Shucks fellas your all too kind. thanks for the compliments on the playing and pedal.

And yep you guys are right its envirotex pour-on , been having pretty good luck with it using a heat gun

[alparent]

Jim.....you actually etched the switch washer! Never thought of that. 

[Mustachio]

Haha Yeah I almost forgot it! Last minute I ran upstairs and etched it. I had drawn on it with etch resist pen earlier in the week and it was just sitting on my desk. I gotta say though the white plastic washer didn't look bad on it. But I really wanted to give it a try Ive never etched a washer before. Gave it a light sanding with 1500 grit before I put it on.

[Ronan]

A couple more outstanding pedals...just keeps blowing me away! 

What can I say, very nice pedal Jim!

I'm starting to feel for the judges, gonna be some difficult judging going on.

[Govmnt_Lacky]

Little over 5 hours to go people!!! 

[haveyouseenhim]

My HEART is racing....

[Jdansti]

Well I've finally got it all together and have found time between family events today to post.  I have great admiration for you guys who were able to get your projects turned in earlier.

My entry is a tremolo called the" Pulsinator". I was originally going to call it the "Treminator", but an online search revealed that someone else was already marketing a tremolo under that name.   I wanted to use a 555 timer for the LFO as a challenge, and boy was it!

I had run across Dead Astronaut's (Rob Henry) Tiny Tremolo which feeds the guitar signal through an LDR which is controlled by an LED connected to the output of the 555.  To be different, I placed a Tillman preamp in front of the LDR to keep the signal's quality in tact (or even make it better). The biggest problem with the 555 is the ticking noise that permeates most audio circuits that share the same power supply.  The Tiny Tremolo avoids this problem by having a separate ground for the LFO and the LDR since the LDR is passive.  The Pulsinator on the other hand has an active amplification circuit and shares the ground with the LFO.  I was able to knock almost all of the ticking using a suggestion that Jon Patton had given to another forumite. Thanks Jon! (BTW, that "Big Bertha 4700uF cap shown in the photos did the trick! ).  I also found Small Bear's "Tremulous Bear", which is a nice 555 based tremolo that uses active components to isolate the ticking.  Steve's configuration of the 555 gave me much more control over timing than I would have had otherwise had, so thank you, Steve!

The next problem I ran into was a popping sound unrelated to ticking from the power rails.   This only occurred when there was a signal going through the Pulsinator.  I was able to reduce this quite a bit by using an external pot to control the intensity of the LED in the optocoupler.

I did an extensive amount of research  trying to finding a passive filter to smooth out the 555's square wave.   I finally settled on a diode/capacitor arrangement that did a pretty good job without greatly affecting the volume or overall sound.   I made the filter switchable between four levels of smoothing.

Once I got past the hurdles above, I had stupid irritating problems. This was the first time that I had designed a PCB. It took me a little while to realize that I didn't need to reverse the PCB image before doing the photo transfer, just the text on the board.

I downloaded the base artwork for the enclosure from a clipart site and then edited it using several drawing programs. The biggest problem with the art was getting the photo overlay on the enclosure without blemishes or uneven cuts. I finally got it and did a varnish clear coat.

On to the videos. I shot several segments of video using my iPhone. They looked good when I viewed them on the iPhone, but  when I transferred them to the computer, they were upside down.  So I had to spend more time finding a way to flip the video.  BTW, being tired when I shot the video didn't help my mediocre playing abilities.

Here are the build documents. I apologize that I haven't had a chance to convert these into jpeg images and post them directly, but I'll flow edit follow up and do this. The docs have been updated for new components and trace cuts that appear in the photos further down.

https://www.dropbox.com/s/0mwqr9mbk02slnt/Pulsinator%20V1.02%20Scheme.pdf

https://www.dropbox.com/s/brcfs18amqh787o/Pulsinator%20V1.02-Copper.pdf

https://www.dropbox.com/s/0zsfzlz3igpeq9c/Pulsinator%20BOM.pdf

Here are my photos of the outside and inside. The board is copper side up because that's the only way it would fit. The copper spring on the back of the board is soldered to a large ground plane to provide grounding of the enclosure. Not shown are two strips of foam attached to the inside of the lid to prevent the board from contacting the lid. I tinned the copper to give it a silvery "Terminator" theme look.











Here's my embarrassing video:

I want to thank the judges for conceiving this contest and running it. Your time and talent is greatly appreated!  Thank you also to all the sponsors (including judges) who generously donated the terrific prizes.  Of course, without Aron, not only would the contest be impossible, but there would be no data source for the wealth of information that we DIYers rely on.

Finally best wishes to all of the other contestants.  This has been a lot of fun and so far you've all submitted projects of a magnitude that I can only dream of.

Edit I forgot to post an image of the component layout on the board. I'll do that ASAP.

[haveyouseenhim]

Nice build John      I'm really diggin the theme!    NOW GO EAT! you deserve it.

One thing you can do to connect the ground plane to the box is to use a thin gauge wire from the ground plane and tuck it under the bypass switch and tighten it down to hold the wire to the enclosure

[GGBB]

Yeah - love the theme - I can tell you really put your heart into it. (It had to be said.)

Sounds fantastic too - great job!