New to MegaDrum - beginner questions

[dmitri]

There are several programming tools, e.g. PonyProg2000, avrdude and etc. You will need an ISP cable to program Atmega with them.
With the bootloader you need buttons no mater if you're updating over USB or MIDI ports. See viewtopic.php?f=3&t=111

From the thread on the bootloader it seems as though in addition to mandatory buttons, an LCD screen is mandatory as well. I just don't want a screen so I may have to go the ISP route.

No, it doesn't make an LCD mandatory.

[jamdat]

I like the look of having no buttons on the case. From following Japi and Gastric's builds I am probably opening myself up for a world of hurt. But once it's configured, I'm never going to touch it again. I think I'll forge ahead with the ISP route.

Moving on to a slightly unrelated topic - Hi Hat pedals. I am making my own pedal and I want one with continually variable position. I've gone and scoured the 'net and found most people using a 25k or 50k sliding potentiometer. Something about 25k being compatible with drum modules. I went another route and am using a rotary potentiometer. To get 25k, I've chosen a 100k, single turn potentiometer and I'm going to be turning it a quarter turn. That will give me 25k. So far, I've worked on how to get the pedal to turn almost 90 degrees, and the best I've got is about a 100 degree turn. So, my question is: if the effective resistance of my potentiometer goes from 0 to 28kohm, does that make any huge difference in terms of megadrum settings? How does one actually use a variable hihat in megadrum? I assume it's something along the lines of "if resistance is 0, play open sound, if it is 28kohm or greater, play closed sound."

A related question is: how is the pedal connected to megadrum? I see 3 pins for the hihat in the pinout list (power, controller input, and NC (which I assume has to deal with the hihat)). That means that the pedal takes up its own dedicated jack. Am I right here? The hihat wouldn't work without a pedal?

I never realized what went into a pedal! It took me about a day of thinking, calculations, and model building to come up with a way to use a rotary potentiometer. Every time I hit a wall, I gain a new appreciation for the design of megadrum! I'm just excited because soon I will order the final parts and start building!!

[dmitri]

I like the look of having no buttons on the case. From following Japi and Gastric's builds I am probably opening myself up for a world of hurt. But once it's configured, I'm never going to touch it again. I think I'll forge ahead with the ISP route.

These buttons don't have to be visible. You can make 4 pin holes in your case with 4 micro switches under them.

Moving on to a slightly unrelated topic - Hi Hat pedals. I am making my own pedal and I want one with continually variable position. I've gone and scoured the 'net and found most people using a 25k or 50k sliding potentiometer. Something about 25k being compatible with drum modules. I went another route and am using a rotary potentiometer. To get 25k, I've chosen a 100k, single turn potentiometer and I'm going to be turning it a quarter turn. That will give me 25k. So far, I've worked on how to get the pedal to turn almost 90 degrees, and the best I've got is about a 100 degree turn. So, my question is: if the effective resistance of my potentiometer goes from 0 to 28kohm, does that make any huge difference in terms of megadrum settings? How does one actually use a variable hihat in megadrum? I assume it's something along the lines of "if resistance is 0, play open sound, if it is 28kohm or greater, play closed sound."

28k is fine. With a stepped pot, as in your case, the number of steps between 0 and 28k will dictate how smooth transition is between open and closed. A switch is an extreme example of a stepped pot with no steps between open and closed.

A related question is: how is the pedal connected to megadrum? I see 3 pins for the hihat in the pinout list (power, controller input, and NC (which I assume has to deal with the hihat)). That means that the pedal takes up its own dedicated jack. Am I right here? The hihat wouldn't work without a pedal?

I'm not sure what pinout list you're referring to. Variable HiHat pedal has 3 pins: power source, controller input and ground.

I never realized what went into a pedal! It took me about a day of thinking, calculations, and model building to come up with a way to use a rotary potentiometer. Every time I hit a wall, I gain a new appreciation for the design of megadrum! I'm just excited because soon I will order the final parts and start building!!

[japi]

I like the look of having no buttons on the case. From following Japi and Gastric's builds I am probably opening myself up for a world of hurt. But once it's configured, I'm never going to touch it again. I think I'll forge ahead with the ISP route.

I think you should have some micro switches at least inside the case. For example.. if something happens with megadrum and you loose control, you can load defaults holding RIGHT when booting. To upgrade firmware via USB you need to hold LEFT. These are useful functions that you would loose for not having the buttons

Other than that, the rest of the functions can be set with MD Config Tool

[jamdat]

I think you should have some micro switches at least inside the case. For example.. if something happens with megadrum and you loose control, you can load defaults holding RIGHT when booting. To upgrade firmware via USB you need to hold LEFT. These are useful functions that you would loose for not having the buttons

Other than that, the rest of the functions can be set with MD Config Tool

I think I'll take the advice that both you and Dimitri have given me. No switches may be a little too "extreme".

Dimitri, the pinout I'm referring to appears earlier in this thread and is for the Synthex 2.7 version.

32 INPUTS Connector :

1 - GND
2 - GND
3 - Power source for HiHat controller
4 - HiHat controller input
5 - Kick
6 - NC
7 - HiHat Bow
8 - HiHat Edge
9 - Snare Head
10 - Snare Rim
...etc...

I'm puzzled as to what 'NC' stands for. I had always assumed it was something to do with the hihat. If I may describe in words: power goes to the hihat controller, through the pot, and back to megadrum. This dictates how far open the hihat is. The hihat itself is a separate thing entirely?

[dmitri]

NC stands for 'Not Connected'

[jamdat]

NC stands for 'Not Connected'

Well.... This changes things. I have to tweak my jacks board for one. Thanks for the clarification!

[jamdat]

28k is fine. With a stepped pot, as in your case, the number of steps between 0 and 28k will dictate how smooth transition is between open and closed. A switch is an extreme example of a stepped pot with no steps between open and closed.

In terms of the settings in Megadrum, would there be any problem in having a DIY hihat pedal with a potentiometer that is less than 25kohms? What about 10k? 15k? How does the value of the potentiometer affect megadrum? Can it be compensated for?

[dmitri]

In fact the smaller the better. Of course not insane values where it would just draw excessive current from power source.
1k-25k values are fine.

[orsku]

In fact the smaller the better. Of course not insane values where it would just draw excessive current from power source.
1k-25k values are fine.

What disadvantages should there be when using bigger pots? I'm using a 100k pot for my hihat controller and it works just fine.