Optical hihat controller

[dmitri]

Maybe Roland modules provide power source on a tip and take HH pedal signal on a ring?

[jman 31]

Maybe Roland modules provide power source on a tip and take HH pedal signal on a ring?

I did notice that Admir's schematic had his set up opposite from the way yours is dmitri and I was wondering why yours was different. That could be the purpose.

[racer52]

Maybe Roland modules provide power source on a tip and take HH pedal signal on a ring?

I did notice that Admir's schematic had his set up opposite from the way yours is dmitri and I was wondering why yours was different. That could be the purpose.

I am still doing research with this project. Can you tell me how to find Admir's schematic?

...Found it! - (needed to pay closer attention to this post )

OK, so now I see what may be the problem in my circuit.

Admir uses a device that is an actual variable resistor (based on light)
Now.. I am most likely wrong, yet again.. but - Is this a subtle, but important difference in the schematic?

What I used is a device that works like a transistor. It flows current from Emitter to it's collector based on the influence on it's base by the light. I am picturing in my mind that Admirs is a purly resistive device that changes it's resistance...

Am I way off base in this thought process?

thanks

[dmitri]

http://www.edrum.info/hihat.html

The Admir's schematic uses a photoresistor. When I tried it it had noticeable lag and I had to replace the photoresistor with a phototransistor.
As you can see the Admir's schematic does use the tip for power source the ring for the pedal signal. As far as I know Yamaha and Roland have tips and rings reversed compared to each other.

[racer52]

When connected to TD20 what is the voltage on the sleeve?

the following values are with the TD20 connected (TRS as in your schematic) and the light block removed (full light hitting phototransistor)

T= +3.3 V
R= +1.3 V
S= 0 V

LED 1 Anode = 1.25 V

all the above values stay constant, they do not change as light is blocked.

D1 Anode side =.08 V Drops to 0 V whith light blocked

The sound produced out of the TD20 is a VERY tight 'chick' - If I disconnect the opti-controller the cymbal changes to a nearly full open hihat sound (with slight cymbal to cymbal sound)

[dmitri]

I guess you have to swap tip and ring on the opto-controller.

[racer52]

I guess you have to swap tip and ring on the opto-controller.

I tried that...same results

The open circuit voltage reading on the tip & ring from the Roland HHCntrl are both 3.5 volts.

dmitir,
Let's not forget the good news about this DIY internal controller that i have built...
This Internal Opto-Controller actually does produce a varing voltage out,
It seems to work exactly as the Megadrum needs ... I just don't have a Megadrum....yet

I do appreciate your willingness to help me with my specific issue - I just wanted others reading this thread to know that it should not be an issue with the Megadrum.

[dmitri]

If you could get voltage readings on the tip and the ring with a Roland HH pedal (in various positions) I would probably be able to give more help.

[jman 31]

I know you said you hooked it up to a 6v source to test the variable part, but did you try doing that while it was on your module. by this I mean unhooking it from the module voltage source and hooking it only to the battery? Sounds like you have the variable voltage that you need, but not the power. Just a thought.

[racer52]

I know you said you hooked it up to a 6v source to test the variable part, but did you try doing that while it was on your module. by this I mean unhooking it from the module voltage source and hooking it only to the battery? Sounds like you have the variable voltage that you need, but not the power. Just a thought.

tried that too... did not control the TD20

I don't think that the TD20 is looking for a variable 'voltage'
I get the feeling it wants to divide its voltage and sample that...???..

gotta go to work - I am late..