Hi hat controller questions

[mackanov]

Hello all.

Is it normal for the hihat controller signal to oscilate? Mine varies between values like crazy, very fast. Is it possible that this is caused by multiplexers (I designed a board for the 4581s, without the diodes and resistors, but can't find them, so I'm using the 4051s in their places for now)?

Another question, not totally related. Does MegaDrum generate chick notes when the pedal is not fully pressed? I'm getting chick notes when going from open to half-open, for example. Is this normal behavior? The way I see it, the hihat should be closed for a chick to sound, right?

[dmitri]

Hello all.

Is it normal for the hihat controller signal to oscilate? Mine varies between values like crazy, very fast. Is it possible that this is caused by multiplexers (I designed a board for the 4581s, without the diodes and resistors, but can't find them, so I'm using the 4051s in their places for now)?

The HiHat controller should work on 4051 even without the diodes. What voltage range do you get between fully open and fully closed? Does the voltage changes smoothly when you press the pedal.

Another question, not totally related. Does MegaDrum generate chick notes when the pedal is not fully pressed? I'm getting chick notes when going from open to half-open, for example. Is this normal behavior? The way I see it, the hihat should be closed for a chick to sound, right?

Read through this thread: viewtopic.php?f=3&t=716

[mackanov]

I get 2mV fully open and from 57 to 61mV fully closed, changing a lot, on the AltInput (200K slide pot).

[mackanov]

Voltage between tip and ground on the Alt input for the Hihat controller also varies, 1.05V +- 0.01V.

[dmitri]

So, is it 2-60mV or 0.01-1.05V range? And does it change smoothly?

[mackanov]

2-60mV with the slide pot, changes smoothly. The 1.05V is between tip and sleeve with nothing connected and it floats between 1.04v and 1.06v very quickly. My VCC is 4.99 to 5V.

[dmitri]

2-60mV is very small range. It is no wonder you get unreliable HiHat pedal data. It should be at least 0-500mV. Figure out why it doesn't go above 60mV with the slider moved towards +5V. Maybe you soldered a 100 kOhm resistor instead of a 100 Ohm resistor which sources power to the variable pedal resistor or you haven't soldered it at all..

[mackanov]

I'll check it. Should I get 1V with the pedal disconnected, though? What voltage does the ATMEGA supply on this pin?

[dmitri]

Atmega supplies there very weak power only good enough for switch type pedals. For variable type pedals (variable resistors, optical, Hall effect) the power must be provided from +5 over a 100 Ohm resistor.

[mackanov]

I have power between ring and sleeve on both hihat control inputs, +5V. I'll run some more tests tonight and see what I come up with.