Optical hihat controller

[dmitri]

Dimitri-
Could the 5k6 resistor be replaced with a 10K or with 5k? My local radio shack doesn't carry anything close to 5k6, so I'll be stuck using 2*10K in parallel with 4*150 in series to get 5k6 equivalent . Wiring up 2*10K in parallel at least gets me to 5k. I don't understand how this resistor affects the circuit so I don't know how accurate this value needs to be.

I think you can use anything between 3k3 and 8k2. Maybe even 10k.

[Thurston]

I have the circuit wired and temporarily attached to PVC using a method adapted from racer's. I want to test using MCT and my synthex 2.8 board but am uncertain about the wiring between megadrum and the optical circuit.

With the exception of 5K resistor in place of his 5K6, my circuit follows this schematic provided by dimitri:


I will be wiring directly to the 32 input connector cable connected to the megadrum board. dimitri's wiring diagram for the 32 input connector shows connection to the the hihat pedal jack (J1) as follows:
Tip: pin 5 or pin 3 depending on SW 1 position
Ring: pin 1
Sleeve: pin 40

I don't think this is correct for Synthex's MD design. His schematic as found in the the PCS v2.8 manual gives the following 32 input connection pin assignments:
1 - GND
2 - HiHat controller High impedance input
3 - HiHat controller Power source
4 - HiHat controller Low impedance input

How should I make the connections? My guess is:
Tip: pin 2 or 4
Ring: pin 3
Sleeve: pin 1

And a related question, what is the purpose of the SW1 switch in dimitri's schematic and the High vs. Low impedence pins in Synthex's?

[dmitri]

I don't think this is correct for Synthex's MD design. His schematic as found in the the PCS v2.8 manual gives the following 32 input connection pin assignments:
1 - GND
2 - HiHat controller High impedance input
3 - HiHat controller Power source
4 - HiHat controller Low impedance input

How should I make the connections? My guess is:
Tip: pin 2 or 4
Ring: pin 3
Sleeve: pin 1

Tip to pin 4. Ring and Sleeve as you stated.

And a related question, what is the purpose of the SW1 switch in dimitri's schematic and the High vs. Low impedence pins in Synthex's?

To choose between HH pedals with high or low output impedance. The optical HH controller is a low output impedance pedal.

[Thurston]

I have wired up the circuit and I'm working on a inside-hi-hat mechanical design that pretty much copies racer's great idea.

What MD configuration settings should I start with for this?

So far MD sees only wide open hi-hat. When I slip a piece of cardboard between the LED & phototransistor nothing happens. I've looked over the wiring for shorts and bad connections but everything looks ok. I thought that if anything I would have trouble getting an open hihat signal (transistor sees 100% of LED emission), but the opposite is happening. I'm going to double-check my wiring to make sure I haven't over-looked anything when I get home, but I thought this could also be an issue with my config settings.

[dmitri]

I have wired up the circuit and I'm working on a inside-hi-hat mechanical design that pretty much copies racer's great idea.

What MD configuration settings should I start with for this?

So far MD sees only wide open hi-hat. When I slip a piece of cardboard between the LED & phototransistor nothing happens. I've looked over the wiring for shorts and bad connections but everything looks ok. I thought that if anything I would have trouble getting an open hihat signal (transistor sees 100% of LED emission), but the opposite is happening. I'm going to double-check my wiring to make sure I haven't over-looked anything when I get home, but I thought this could also be an issue with my config settings.

When you close the phototransistor, watch voltage on it's emitter - it should go down a few volts. Do you see it happen?

[jman 31]

I'm embarrassed to even have to ask, but I've been killing myself over this for hours. I built the is circuit using my own tutorial based on Dmitri's schematic, and I can't get it to show any change. I hooked a 4v source up as follows: ground to sleeve, +4v to the tip, and I am measuring the output on the ring and sleeve with a DMM. I am getting full voltage on the meter which tells me that the phototransistor is allowing all of the voltage through, but when I cut off all light to it I get no change. The only thing I can figure is that I am measuring the wrong points. I have built this same circuit before and it worked fine.

Any suggestion would be greatly appreciated.

Jman

[dmitri]

I'm embarrassed to even have to ask, but I've been killing myself over this for hours. I built the is circuit using my own tutorial based on Dmitri's schematic, and I can't get it to show any change. I hooked a 4v source up as follows: ground to sleeve, +4v to the tip, and I am measuring the output on the ring and sleeve with a DMM. I am getting full voltage on the meter which tells me that the phototransistor is allowing all of the voltage through, but when I cut off all light to it I get no change. The only thing I can figure is that I am measuring the wrong points. I have built this same circuit before and it worked fine.

Any suggestion would be greatly appreciated.

Jman

My guess is that you swapped emitter and collector of the phototransistor.

[jman 31]

My guess is that you swapped emitter and collector of the phototransistor.

You were right, thanks a bunch! RadioShack had it marked wrong on the package. They had the flat side of the detector marked as the collector which was opposite of what it actually was. Boy I'm glad that's figured out. That could throw a lot of people for a loop. It didn't make sense to me, seeing as how an LED usually has the flat side to negative, but I would expect them to get their packaging right.

[jman 31]

Hey Guys, I built one of these for my MD, but I am not getting any response from it. I know it is working because I ran test voltage through it to make sure. Could someone post their settings with this controller? Also would this be considered a foot pedal or a pot?

[jman 31]

Hey Guys, I built one of these for my MD, but I am not getting any response from it. I know it is working because I ran test voltage through it to make sure. Could someone post their settings with this controller? Also would this be considered a foot pedal or a pot?

Update: I can't get it to act consistently at all. I get an open hat sound when I first turn on midiox. When I plug in the optical controller I get a closed hat sound when I hit the pad. I get no change whatsoever when I insert a blocker in the optical controller. However when I remove the HH controller the pad continues to register a closed hat sound.

Here's more that I don't understand.... sometimes when the blocker is inserted I get a midi response, but other times nothing. When I plug in the HH controller sometimes the midi note scrolls endlessly and sometimes it doesn't resister anything. It is so inconsistent that I can't zero in on anything.

Any help would be greatly appreciated!

Jman