Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How to translate a large variable resistance to a low variable resistance

Status
Not open for further replies.

Waynec42

Newbie level 3
Joined
Nov 25, 2012
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,316
Hi,

I'm new to this forum so I hope this is the correct place for this question.

Having studied electronics a number of years ago, I'm not as knowledgeable as I would like to be in regards to analogue circuits, but I'm sure what I'm trying to do is possible.

Here's the question.

I'm a drummer. I play an electronic kit (2box brand). The foot pedal that simulates the hihat has a variable output of 700Ω to 800Ω. I would like to use a different brand of foot pedal (Roland) for this input. The problem being that the Roland foot pedal is 0Ω to 20kΩ as well as being reverse polarity - 20kΩ to 0Ω.

Can anyone recommend a simple circuit to translate a 20kΩ to 0Ω input to a 700Ω to 800Ω output.

Thanks.
 

Hi,
Connecting a suitable resistance in parallel would make it.
 


That will turn a high resistance into a low one but the problem requires the opposite. Also, it won't reverse the direction of travel.

It may be possible to use a simple transistor circuit where the pedal progressively turns on a transistor with an open collector/drain with a series resistor added. Most modules simply have a pullup resistor (to 5V) internally - maybe you could measure yours?

My main concern would be how progressive it could be. I could look tomorrow to see what might work. My main experience is with Yamaha modules.

Keith
 

That will turn a high resistance into a low one but the problem requires the opposite. Also, it won't reverse the direction of travel.

It may be possible to use a simple transistor circuit where the pedal progressively turns on a transistor with an open collector/drain with a series resistor added. Most modules simply have a pullup resistor (to 5V) internally - maybe you could measure yours?

My main concern would be how progressive it could be. I could look tomorrow to see what might work. My main experience is with Yamaha modules.

Keith


Thanks for all the replies.

Unless I haven't explained myself correctly or I'm misreading it, I do need to change the high resistance into a low resistance. The other part is correct about reversing it.

I like the transistor idea. I'd have to re-learn it all but from what I remember about transistor theory, this sounds promising.

I look forward to further suggestions from people who know more than me.

- - - Updated - - -

Hi,
I think this will work. Pls follow the link
https://obrazki.elektroda.pl/1964705400_1353850533.png

Thanks for this, but I've actually tried this method. I found it works in theory but isn't linear enough. It goes from no change to a sudden maximum change. I can't remember which direction though.

Keep them coming though.
 

Sorry, I misunderstood.

Do you actually have a Roland pedal? If not, the Yamaha pedal works (HH65 I think) the correct way round for you needs and although the resistance is very high it is set by fixed resistors on a PCB which are progressively shorted out so could easily be changed.

Keith
 

Sorry, I misunderstood.

Do you actually have a Roland pedal? If not, the Yamaha pedal works (HH65 I think) the correct way round for you needs and although the resistance is very high it is set by fixed resistors on a PCB which are progressively shorted out so could easily be changed.

Keith

Ok, thanks for the info. I don't have a Roland pedal, but I have access to one for testing purposes. I don't want to purchase one if I can't use it.
I'll look into the HH65. You wouldn't happen to have a circuit diagram for the HH65?
Cheers.
 
Last edited:

Yes, see attached. The pedal works by having conductive rubber which progressively shorts out the resistors through pads on the PCB. You end up with a low resistance when the foot is pressed on the pedal, which I assume is what you want. The resistors are standard through hole, so easily changed. The ring connection is to do with the splash, I believe, as is the diode/capacitor. Roland modules don't use the connector ring - I don't know about the 2box.

I assume you have seen Jman's posts about hihats on the unofficial 2box forums?

Keith.
 

Attachments

  • HH65 pedal.pdf
    42.6 KB · Views: 51

Yes, see attached. The pedal works by having conductive rubber which progressively shorts out the resistors through pads on the PCB. You end up with a low resistance when the foot is pressed on the pedal, which I assume is what you want. The resistors are standard through hole, so easily changed. The ring connection is to do with the splash, I believe, as is the diode/capacitor. Roland modules don't use the connector ring - I don't know about the 2box.

I assume you have seen Jman's posts about hihats on the unofficial 2box forums?

Keith.

Thanks for the pdf. I'll have another look at the 2box forums. There's a fair bit on there about hihat options.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top