Roland HD-3 Drum module issue

[Rockstar Okan]

Hi everybody;

I have Roland HD-3 electronic drum kit and module. I want to connect 2 pedals to one kick input. Please help me about this.



Here are my determinations:

Standard pedals are variable resistors. In the top position, i measure 20.2 Kohm. In the lower position, mesure to 5-6 Kohm. But it "beats" about 12,50 Kohm.

actually, this resistance changes sets voltage on kick input jack.

Here are measurements:

No load: 3,28 V
When pedal connected: 20,19V
"Beats" 1,60-1,80V

I've tried adding serial 20 Kohm resistors both pedal (total 4 parallel 20K ohm, 2 of standart fixed, 2 of variable-already pedals) but it is not working correctly.

I need these:

A circuit that have 2 inputs that both detects connected variable resistances (pedals). When one of them falls below 12,5 Kohm, the circuit sends to output a logic signal (maybe) and reset instantly. For fast double kick drumming, it must be done.

Second circuit that detects any logic signal on it's input. And sets output resistance (or resistance at output) between 20 Kohm and 12.5 Kohm. It may be a photo resistor driven by led.

My head is exploding! What can i do?

I'm thinking about 555 monostable one shot topology for second circuit. but it works when input shorted to ground. How can i do?



Circuits Page 9

Please help me, waiting for answers from Masters.

Thanks. Okan.

[paleeman]

Hello Okan. I think you're on a wrong foot here, because Roland KD kick triggers, use piezoelectric sensors, (not variable resistors) thus producing electricity on the output. Are you familiar with Roland's KD-120? It has a double pedal feature. Or even better, the KT-10 has a MIX IN TRIGGER input for the the second pedal.

[Rockstar Okan]

Hello Okan. I think you're on a wrong foot here, because Roland KD kick triggers, use piezzo sensors, not variable resistors. The KD-120 has a double pedal feature.

No. The pedals has carbon coated flexible ribbon cables. I know what piezos looks likes. When you press down the pedal, a metal piece applies some preasure to ribbon cable for resistance decreasing. I can take some photos if necessary. Thanks.

[paleeman]

I am not saying, that you do not have the resistor sensors, I was referring to the Roland KD triggers in general. Roland KD series use piezos.
I am suggesting to you, not to engage in such encounter with the NE555 and whatnot, because if you play music professionally, you need something 100% accurate and reliable when you perform. And this would certainly not give you the result you're looking for.
In my opinion the KT-10 is the most simple and cost effective solution.

cheers

[Rockstar Okan]

Yes, you are right.

But, i am doing this project for my friend. He has 2 HD-3. His setup has 6 toms 6 cymbals etc. But he selects different kits from each unit. whops, kicks are different. 2 kick pedal must be connected one unit. I told him. Buy another kit but he didn't listen me. He spend his money one time. I have to solve it with the material in my hand.

You know, we are friends!

[paleeman]

I fully understand your situation. Then I suggest to use the CD4001/CD4011 combination. With the logic circuits and some voltage dividers you can derive a single output, from two pedals, by finding the proper threshold to trigger the logic gates.

Good luck!