Author Topic: Crappers Digital Stomp Box  (Read 8307 times)

Crappers Digital Stomp Box
« on: November 24, 2011, 06:42:09 PM »
This is a continuation of my first posting for a DM6 called:

DM6 Foot Triggers

I decided to start a new thread because this will be a description of a complete project that I hope you will find interesting.
If you have read my previous thread, then you will know that I want to create a foot switch that will sound drum voices with both up and down foot movements. I have tried a number of prototypes for this, but have now decided that the way forward is to use some kind of active circuit.
While searching the net for a solution, I came across many examples of a 555 monostable timer circuit. This circuit can be made to produce a single pulse for a fixed time after a switch has closed. I stared wondering if this pulse could trigger a DM6 voice in place of the more commonly used piezo. My original idea was just to use the 2 switch inputs available on the DM6, but if my hunch was right I might be able to trigger all the voices with this circuit.

Well guess what? I was right  ;D

I constructed a breadboard circuit using a 556 chip, which contains two 555 timers and fiddled around with some component values until I got it working. It seems that the trigger inputs to the DM6 need a fair bit of voltage, somewhere around 5 volts with a very short pulse. According to the standard time delay calculations I ended up with a pulse that only lasts 200 milli seconds! That is incredibly quick.
Here is a picture of the design that is going to be used for a single foot switch. It has 2 identical circuits in it. One for up and one for down. There are 2 rotary switches to allow for the selection of DOWN - OFF -UP for 2 separate Drum voices. Here is that circuit.


I intend putting 4 of these in one interface box and have 4 footswitches plugged into it. The box will then be connected to the DM6 with a standard RS232 25 way cable. (That octopus cable is a real pain when it gets tangled up. I'll be glad to get rid of it!)
 

Thanks go to ccie5754 for his DM6 pin-out, which you can find at:
DM6 DB-25 Cable Pin-Out

I will keep you posted as the project progresses.

Lou
« Last Edit: December 28, 2011, 04:53:04 PM by Cpl Crapper »

Offline vtdrummer

Re: Crappers Digital Stomp Box
« Reply #1 on: November 24, 2011, 07:00:38 PM »
Very cool... wish I could read a schematic...  ;D
DM10 Studio 2011 w/Surge Cymbals added, BB Mesh head conversion w/rubber muffs at bottom, one 12" A-E pad, Simmons DA200S, sometimes using 2 satellite speakers... Simmons SDMP-1 Multi-pad.
See my DIY 12" Acoustic to E-Drum project post here: http://www.dmdrummer.com/index.php?topic=1227

Re: Crappers Digital Stomp Box
« Reply #2 on: November 26, 2011, 05:45:12 PM »
Let's do the easy part first.
I bought a momentary footswitch from Maplins for £7.99. It's a complete unit which provides an on-off function. It has an Eagle part number G028B. It looks quite sturdy and should stand up to the pounding it's gonna get!


When I took the pedal top off, I found it had a changeover microswitch inside, but they had only wired up 1 side of the switch. So it needs re-wiring for my up-down triggering. Here is how the switch will be wired to a standard TRS jack plug.


This will be one of four that will be plugged into my Digital Stomp Box.

Lou
« Last Edit: November 27, 2011, 04:49:40 PM by Cpl Crapper »

Re: Crappers Digital Stomp Box
« Reply #3 on: December 02, 2011, 05:18:54 PM »
Well, I hope you are all still interested in this project of mine.

Just to remind you, This is basically a circuit that converts the press of a switch into a pulse that will fire a Drum Voice. No need for a piezo and no crosstalk!

I have finished the construction of the circuit board, which is built to let 4 changeover footswitches control 8 DM6 Drum voices. In the picture below the circuit on the top left of the board contains the components needed for 2 triggers wired to a changeover switch. This circuit is repeated for the other 3 footswitches. The complete board contains 8 identical trigger circuits.


Here is a picture to show you the underside of the stripboard. The strips of copper that need cutting are shown with yellow dots.


In the next post, I'll show the connections from the board to the footswitches and the output switch connections.

Lou

Re: Crappers Digital Stomp Box
« Reply #4 on: December 09, 2011, 08:14:27 PM »
Here is the next chapter in my "Stomp Box" project.
For those of you who may be interested, there is a company in the States who make acoustic foot drums. They look really cool. but they are a little too expensive for my wallet!

http://www.footdrums.com

They are designed for musicians like myself, but I like the flexibility and range of sounds you can get from an electronic Drum Module.
I know there are probably not many of you who would actually make one of my Digital Stomp Boxes, but I find that putting up these posts helps me with the thinking process. For example. I have evolved the design to now use rotary switches for selecting up/down/off for the voices. These means I can use some of those chicken head knobs you see on old Fender Amps. ;D

This picture shows where the wires are connected that come from the up/down microswitches. If you remember from a previous post. The tip of the jack is connected to the down contact and the ring is connected to the up. All the sleeves for the TRS sockets will be connected together and go to a GND pin on the circuit board.


The next picture shows where the wires go for connection to the selector switches.


I am currently working on a box to put this all in to.
I'll be able to show you the final assembly in the next post.

Keep on Drumin'

Lou
« Last Edit: December 28, 2011, 06:08:06 PM by Cpl Crapper »

Offline wildbill

Re: Crappers Digital Stomp Box
« Reply #5 on: December 09, 2011, 08:39:28 PM »

...Just to remind you, This is basically a circuit that converts the press of a switch into a pulse that will fire a Drum Voice. No need for a piezo and no crosstalk!...

Lou


Is this basically how units that use a switch for the hi-hats works?  When you step on the switch to make a 3rd sound.  (Open, closed, and foot click).

I'd like to have your skills in this area.  Nice project.

Re: Crappers Digital Stomp Box
« Reply #6 on: December 10, 2011, 07:17:01 PM »




Is this basically how units that use a switch for the hi-hats works?  When you step on the switch to make a 3rd sound.  (Open, closed, and foot click).

I'd like to have your skills in this area.  Nice project.

I don't own a Hi-Hat Control pedal or any drum pads. But I have discovered that there is about 6volts across the tip and sleeve for the Hi-Hat control plug. This does act as a switch because it triggers the Hi-Hat voice when shorted across. My guess is that they are using a circuit similar to mine to convert that switch action into a pulse to trigger the sound. The contact between the ring and sleeve must be causing the DM6 to sound a different voice, ie: open hi-hat, when you hit the hi-hat cymbal. Hope that helps, wildbill.

Lou
« Last Edit: August 22, 2012, 06:54:56 PM by Cpl Crapper »

Re: Crappers Digital Stomp Box
« Reply #7 on: December 28, 2011, 05:20:45 PM »
Well, it's taken some time. I have finally completed the "Digital Stomp Box". I was delayed by 3 Tooth Extractions, 2 Broken Cars (autos) and a Partridge in a Pear Tree (Christmas).
I gave up the idea of triggering the same drum voice from both up and down switching. I found it worked OK on the Kick voice, but didn't trigger consistently on the other voices. No big problem because I can re-assign any trigger to any voice and save them as a custom drum. This will give me the same sound for the up and down presses of the footswitch.

Here is the inside of the assembled box.


Notice the PP3 battery, held in with a piece of velcro. The power from the battery is only connected to the circuit when the 25 way cable is plugged into the Stomp Box and the DM6. Because all the sleeve connections are connected to Ground in the DM6, I'm basically using those connections as a power switch.

Here is the back of the front panel with the 8 rotary switches wired up.


Last picture is the front of the box. I wanted it to look like a cigar box and used them good ol' chicken head knobs.


I've just got to get used to playing the thing now.
I'm also working on a housing for this stuff. I got a vintage single headed 24 inch Bass drum on eBay and I will mount the DM6 and my Stomp Box into it.
I'll post a picture when it's finished.
When I've mastered the footwork required to play this thing, I'll post a video on YouTube so you can all have a laugh!

Have a Good New Year.

Lou
« Last Edit: December 28, 2011, 06:12:59 PM by Cpl Crapper »

Re: Crappers Digital Stomp Box
« Reply #8 on: January 04, 2012, 09:37:18 AM »
The design of the Digital Stomp Box seems to be forever evolving. When I originally tested it, I only had one footswitch wired up. Everything worked as expected.
However, when I wired up 2 footswitches, I found that when I had a cymbal voice switched to the up position on one footswitch, the other footswitch did not operate properly. Because my knowledge of electronics is not that good, It took a while to figure out what the problem was.
I thought that the circuit was sending a short pulse whenever I pressed a switch. What actually happened was that a pulse was produced, but if the switch stayed closed, the signal stayed high. This prevented some of the other voices from sounding. It appears that if you keep a cymbal voice at a high voltage then voices like the toms will not sound.
I found another example of the 555 timer circuit on the web which indicated that I need to add a capacitor to the footswitch contacts that would force it to return to a positive voltage soon after it had been closed. I tried this out on my breadboard and that did the trick. Also as a bonus it allowed me to return to my previous idea of being able to sound the same voice with both up and down switches. The 4 diodes were added to isolate the up and down pulses from each other when both up and down are selected with the rotary switch.
Here is the final circuit that I'm using.


Lou
« Last Edit: January 08, 2012, 03:43:08 PM by Cpl Crapper »