I have designed an ultra easy to build expression pedal but I don't know how to put my drawing details up in a post here for all to see. 

Does anybody know how to post a drawing on this forum?  Please share?

I also have a new PCB design for the GEO A/B/Y that I would like to post for everyone.

It's time for me to start giving back to this awesome site, if I could get a little help from my friends.

KMS

Quote from: KMS on November 12, 2005, 10:08:46 AM
Does anybody know how to post a drawing on this forum?  Please share?

The button is your friend. Look under the posting section and also the "Bulletin Board Code" section.

You will need a web host to store you images that you will link too. Many people around here recommend photobucket. You could use Aron's layout gallery.

Andrew

Check out the About this forum.... link.

http://www.diystompboxes.com/smfforum/index.php?topic=21.0

You can use the layout gallery schematics folder to host your pictures.

Thanks!

Aron

I've been thinking of a way to build one myself and have a good idea, I'll wait to see whether your idea is the same as mine or whether it's better or whatever

Thanks for the info Tone God and Aron.

Well, it is not as easy as I wanted.  But it will be strong and last a long time as opposed to some of the other ones I've seen made out of a steel stud box.

I put the images in this forums archives so we can go back to it and if needed, I might do some updates and make a front view.  For now I covered most everything with a side view plan.

I have not made the box yet, but my luck has been holding out real good on mechanical design for the last 20 years so I'm not too worried about it.

For those that are not too good with their hands on applications, try using hot glue to set each part before drilling the final hole. It is best to first drill holes in one part (like the hinges) in vise first, then set the part on the next piece and mark it with pencil, then apply a dab of hot glue to the part and quickly press it in place. The glue will hold it as you drill through the hole you already made into the final piece. Alignment of the door hinge will be crucial and I advise to use some method that will keep the parts from moving while you drill the final holes. 

The PCB for Geo A/B/Y will have to wait until I test it. Probably next weekend.

Man, drawing this stuff is hard to do!

Enjoy!







Note this set up uses a slide pot (s) and you can put as many pots in there as you can fit. All you need is to install a wider actuator plate and glue a series of pots together.   Different value pots too and if your ambitious you can wire the pots to a big DPDT rotary switch and then use a micro toggle DPDT to control the rotary such that you can use the pots in series or parallel and thus have a multitude of ranges that can be used on a multitude of other stomp box functions, like the speed on your delay, the speed on your flanger, the speed on your flanger and delay at the same time, the tone on your favorite distortion.....the possibilities are endless.

I'm not sure if I'm reading this correctly.. but it seems as though your pot will only be able to have half motion, if that. So a 500k pot could go from 0 - 250k or 200k - 450k and so on. Am I right?

Quoteit seems as though your pot will only be able to have half motion

My pot has 1-1/4" travel (the total outside dimension of the Stackpole 117 pot casing is a little less than 2-1/8" ) At 8-inches from the center of the hinge the pedal has 1-1/4" travel on a flat surface with the face of hinge 1/2" above the flat surface (I tested this today just to be sure).  The drawing is not to scale and I guess I should make a note of that fact somewhere on an update, but I will wait until I finish my box and update it then (sometime this winter).  I will be building two of them.   

I priced all the stuff today at about $30 per pedal and that is if I buy for two pedals.  If you buy for just one pedal, there will be a lot of waist that could be used on other pedals in the future, but most of this stuff is pretty specialized just for this pedal.

Notice how the rear of the box is on an incline.  That should allow a lower elevation (1/4" maybe) on the hinge and still get 1-1/4" travel at 8" from the center of the hinge or it would allow me to set my "Actuator Plate" closer to the hinge than 8".

The plan is to have full travel on my Stackpole 117, but I doubt I will need it.  Most applications would only need about 250K to make the circuit expand to it's limits.  I will probably set the stops so my travel is limited to about 3/4" but I'm not sure yet as to what part of the pot I will find pleasing to the ears. I think that stopping at about 250K will do what I need and because we are talking about log pots here, that ends up being exactly 3/4" travel to achieve the 250K on the Stackpole 117.

The Mouser equivalent that I noted in the details is almost exactly the same size as my Stackpole and a little cheaper (my Stackpole was $1.50) but the Mouser only goes up to 100K.  It has just a little less travel than the Stackpole. 

Mouser also carries an Alpha Series that is 500K but it is 3" long and has about 2-1/2" travel. 

Also note that most Dunlop pedals have about 3/4" travel at the pot location.  My thinking here is that we don't want to deviate to far away from the well proven pedal travel of the Dunlop.  That way, what many of us have practiced on a Dunlop we can easily transfer to this pedal.  Also the Dunlop has the hinge 2-3/8" from the heel end of the pedal.  It makes since that the hinge should be close to the heel because folks have a lot more power on their heel than their toes so this will allow an even and natural feeling muscle action to operate the pedal.

I looked into almost every aspect I could think of to incorporate into the design and my design has a lot of what you would see in a Dunlop Pedal including the "Drag Plate" compression rings (I got that straight out of my Dunlop except they only use one ring and it is located on the Actuator).

The main problem I ran into was coming up with something to make the very weak steel stud box strong.  The 2x4 wooden block solves that problem but makes the box a little hard to take apart if needed.  I originally was going to use a 2" angle iron in place of the wooden block, but it cost $10 for 36" piece and woe to all of us that would cut that damn thing wrong and then need to cut it again. 

If anyone needs to put a battery in the box, put it in the back section (easy access) but remember to drill a hole in the 2x4 block before mounting the wooden block assembly so you can run your wires through the block.