Button Light Matrix help...

[Harley Godzisz]

Hi guys, my 1st post on here... and i've just got my head around the general MIDI setup of things! :D

My main question....

I have found a couple of schematics on this forum / website for dual coloured Button Light Matrix's, I'm after a single colour BLM.

My project incorporates:

200 Pots

244 buttons (push to make contact - momentary switch)

...and I want every button to illuminate and stay on when I let go untill I press it again for it to deluminate, or in the case of some of the buttons, i press one of two buttons, for it to turn the other off and illuminate it's self (Dutton 1 is on, button 2 os off. I then press button 2, button 2 illuminates, and button 1 turns off. And the same like wise.)

they are gonan be coloured buttons so i only need the 1 colour (clear) in each button.

2nd Question:

I would also like a STEREO VU meter on each channel, is there any other way of doing this other than getting a HUGE I/O setup with the comp?

How do i achieve this?

Forgive me.. i'm a bit of a noob :o)

Many thanks all!!

[Max Romantschuk]

I'm sorry but I don't think anyone is willing to do the hours and hours of research and planning your project entails for you. You need so spend some time looking at ucapps and the wiki linked at the top of the forum. Once you have a real plan, not just a fancy idea, post a new post to this thread on how you plan to build your box. Then I'm sure people will be happy to help you with ironing out the details.

I don't mean to sound harsh, but the Do It Yourself idea with midiboxes is just that... :D

[Harley Godzisz]

sorry id my frst post ws a bit vaigue, i was knackared and posted juat just before i went to sleep. (UK - London here)

Hi Max, i've done alot of research on it to the extent i'm thinking abot it 24/7 now... it's taken over my life!! haha.

I've already got the designs for the panel.

I understand that each core can handle 128 Digital In's, 128 Digital Out's, and 64 Analogue In's, and 64 Analogue Outs.

So working on that basis, 200 pots will need 4 cores, 244 buttons on their own would need 2 cores.

Also, I would need 7 Analogue In Cards, and 8 Digital In Cards

= 4 cores needed if i'm correct.  I would have this broken down to 2 analogue in's and 2 digital in's per core, with the 4th core with only 1 analogue in's and 2 digital in's.

I understand that.

Now....

I found a PDF schematic of the BLM with Dual LED's (red / green).  Is it just a matter of NOT connecting the RED ones if all I want is a light to come ON and stay ON when I activate the function on the computer (press the button), then to turn off when I press the button again?

I'm not asking for people to do hours and hours of research for me :P, i just can't find ANYTHING on VU meters, or anything explaining in simple english a BLM. :S

Even just a couple of schematic's for me to work with?

I will be doing a running blog of the build from scratch. And although this may be my 1st build, I'm gonna be using this for years to come.

Thanks people :D

[stryd_one]

200 knobs? Why no paging scheme?

If you want real VU meters, then google around for some DIY audio sites, if you want bar graphs that will display 'something sent via midi', there is info around here. (not great amounts of it, but it's there)

There is no 'plain english' info on the BLM's inner workings, but if you write it, there will be ;)

[Harley Godzisz]

200 knobs? Why no paging scheme?

A paging scheme? how would that help?

[stryd_one]

Less knobs, less space, less cost, easier accessibility, segregation of similar controls, easier use.... Should I go on? :D

Maybe you thought I meant memory paging or something? That's not what I meant, I meant as in , there are knobs 1-8. In page 1, they act as controls 1-8, in page 2, they act as controls 9-16, page 3, 17-24, etc etc etc. You don't need (or want, in most cases) a physical knob for every control you want!

[Harley Godzisz]

On each channel i have (in order):

Gain

Hi Freq

Lo Freq

Hi

Mid

Lo

Pan

Volume (fader)

Basically, I hate using a mouse with music software. I would feel much more in control if i had a "replica" of a proper studio mixing console.

[stryd_one]

So, I take it that you want 24 channels + a master? Then for example you build 8 physical channels and have three pages. That works best with motorfaders, but still works well with pots in soft-takeover mode.

[Harley Godzisz]

nice idea, i might do something in the future using a paging scheme...    But I like my consoles to be bulky and full of buttons and pots and faders!

here is an image of what i'm going to do:

Now the small lower space is for a ball mouse / touch pad (depending on what i decide), but the top bigger space.. i'm not sure what to put there, i was thinking about having a drum pad like the "M-Audio Trigger Fingers", but idea's welcome for that part.

[stryd_one]

Ahh, ImagesHack. I never can get an image off that site without allowing tracking cookies and other such evil things... would you mind attaching it?

Anyway... you sure have you sights set high! Best of luck!

[Gridracer]

Hello Godzisz,

I  had to get myself read into this BLM stuff just some weeks ago.

Perhaps it helps to think about the basic concept of a scan or display matrix first:

"Matrix" here has nothing to do with the position of the buttons and led's on your panel!

It is a concept to handle a large amount of buttons and led's with a smaller amount of

in and outputs of shiftregisters:

Think of 100 buttons e.g. without a matrix you will need 100 DIN pin's so each button is

connected to one pin.

By using a e.g. 10x10 scanmatrix you will only need 10 output pins and 10 input pins, while the outputs

are connected to the rows of your matrix and the inputs are connected to the columns of your matrix.

But you will have to use a technique called multiplexing, that means, only one output and therefore

row will be active at one time and  current will "flow" thru the matrix so that the inputs can read the information from this active row. Then the next row is activated by next output and scanned by the inputs, then the third.... this switching is done faster than anyone can push a button and has to be realized by your software. Basically the same with a LED display matrix, but here you use outputs for columns and rows, switching is faster than your eye can realize.

Two problems come along with a BLM matrix, on the scan matrix you could have some undetermined states where the input could not "know from which button the current came from" this can be avoided

by adding a diode to each button which restricts current flow to only one direction.

On the display matrix you have the problem that output connected to one row has to "take" the current of all LED's in one row (if all are on) there is a workaround by using low current led's but the propper way to do it is to use a special IC thru which the curent will flow and which can take it. The shiftregister output will only drive this so called sink driver. Also as a Row is only active when scanned the LED gets less current

in average compared to a permanent on one, so to get the same brightnes you have to drive it with higher current.

So this is what i have sorted out, if i wrote something wrong, please anyone correct me.