MIDI percussion bass

[Mexicanfunkman]

I really want to learn to make one myself

[mikulasvselicha]

well yeah... almost like Futureman :-D :-D :-D

[taptronics]

first answer is yes.

the piezo and pre-amp delays is in miliseconds, you don't need to worry about slew rates. You can't make faster than that. That's is why to increase velocity you have to convert this linear input into log table. For example 0 mV, 250 mV, 500 mV, 750 mV , 1 V will associate with 0 mV, 500 mV, 800 mV, 1 V, 1.5 V respectively.

[mryellow123]

I wrote a PIC drum controller but then ended up buying an Alesis D4 when the memory pages ran out :-)

I was taking 2 samples of the input and comparing them. So you'd end up with a representation of voltage increase over time. The harder the hit, the faster the voltage spike would spike, with a larger difference between the samples..

Only got to test this with hex values on screen and not actual sounds.... Seemed right....

The technique sound you think?

[mryellow123]

doh I've asked that before :-D

[taptronics]

So to answer your question, velocity is  controlled by both of them. first is analog gain which is controlled by potentiometers and secondly, the digital results of ADC are manipulated by code inside the firmware to get desirable either linear or logaritmic rsponses.

[mryellow123]

So the amp gives it a good enough attack to the signal so you can just use the voltage via ADC? voltage = velocity (after going through table)?

There is a little delay in the triggers voltage taking off and I found that the faster the voltage increases the more velocity it was likely to be hit with....

You used the pre-amp to do that? By making the voltage from the hit nice and manageable first?

[mryellow123]

oh I see the photos now.....

On the cable, I found you can get good flexible multi-core robotics cable.

For plugs, Binder-USA has some great locking multi-pin connectors of various kinds.

How much for your trigger brain?

Velocity sensitive?

Latency?

Quirks?

[taptronics]

I am not selling this Brain anymore , It is going to be replaced with new version, which has smaller board and less cost.

It's velocity sensitive controlled by pots for each trigger. You will not notice latency when connected to most drum machines such as Yamaha , or Alesis but if we play it through PC it depends on how fast the MIDI/sound drivers to process MIDI input from this Brain.

[mryellow123]

velocity sensitive to touch with a pot to adjust level?

or

velocity set by pot?

The code I was running took a few samples and by how quickly the voltage was increasing it would create a velocity for the midi msg. Similar technique?

[taptronics]

This pots to adjust amplifier gain when we touch the piezos. This analog signals between 0-5 VDC fed into Analog to Digital Converter (ADC). Meanwhile there is part of code I written contains "tables" which we can choose either linear or logarithmic modes to manipulate MIDI velocity values and these tables to be selected by external switches.

I suggest you to create logaritmic table due to human ears response to audio volume.

[mryellow123]

What are you using as a brain?

I coded one for PIC16 but then realised Alesis D4 go cheap on ebay.....

[goinghomesic]

can u play n e thing

[gysmazar]

cool, where is your web site?

[taptronics]

w w w. t a p d r u m.c o m

[thedean64]

how expensive is everything?

[taptronics]

16 pads for $200.

[takenxtx]

Very nice,how long did that take to build..?

[taptronics]

1-2 weeks for building box(instrument's body) 3-4 days for assembling electronics parts.There is instruction to build triggers (piezo sensors) on my website.Even you can replace box with cupboard , just lay the sensors on it.

[wokensoulsounds07]

hey man, thats quality...can i really build one myself though?

:)

[taptronics]

Yes, You can.