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8x24 LED matrix


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Maybe I'm overthinking it. I think it would be easiest to specify two separate matrices (16x8, 8x8). If the matrix is 8 rows tall, then I think it should still work to specify the same shift register for the selection pulses.



DOUT_MATRIX n=1  rows=8  inverted=0  sr_dout_sel1=1  sr_dout_r1=2  sr_dout_r2=3   led_emu_id_offset=1001
DOUT_MATRIX n=2  rows=8  inverted=0  sr_dout_sel1=1  sr_dout_r1=4                 led_emu_id_offset=1129


Edited by latigid on
single colour, proper maths
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  • 1 year later...

Hi guys hope every one is keeping well

I am a midbox newbie and i was hoping that  someone could help me with led matricies I am trying to resurrect a project which i initally started with a livid diy builder platform.

my question centers around rgb led matricies

At present i have several rgb matricies each  are 2 rows 4 columns connected to a 10pin idc

pin 1 is common anode column 1,

pin 5/6/7/8/9/10 are for the cathodes and are assigned to rows  123456 respectivley.

Not sure what pins 234 are doing but these are assigned to columns 234 respectivley.

is there a way to hard wire the 2 by4 rgb led matrices to create a larger matrix so i can reduce the number of D outs i need.

I have 72 rgb leds (standard) 56 are associated with encoders i am hoping to eventually hack the board (livid rgb omni) replace the leds with connectors  that go to assignable leds layed out in a strip and get better visual feedback.

 i would greatly appreciate any pearls of wisdom anyone would like to share. feel free to PM me.

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You can create a matrix with 9x rows (sink side) and 8x3 columns (R/G/B source sides).

So you need 5x 74HC595 chips because they only have 8x outputs. You also have 7x rows spare as it is a 16x8(x3) matrix.

If you have buttons you can connect 1x DIN 74HC165 chip to the columns with diodes to the switch inputs. 


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Appreciate the input  have looked into the shift registers i have more questions re going from the idc headers to the shift registers. I think what i would like to do is create 3 separate matricies  of rgb leds each is 4 columns and 6 rows total (72 leds) have 3 sepaate matricies.

if poosible can i pm you.

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MB_NG supports multiple matrices. You just need to define the shift register where each block of 8 is connected. If any block is less than 8 wide, no problem. It will just take more shift register chips to address them. 

Best idea is to draw a circuit diagram of how the LEDs are arranged. Then for each contiguous block, that is one shift register with a maximum of 8 rows or columns. You probably need sink transistors (NPN) on the rows unless your current draw is low. 

Please keep posts public so other travellers can benefit from any knowledge or lessons. 

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Thank you latigid on

im in the process off creating my first circuit diagram,  at the moment it looks like noodles intermixed with blocks however i have just been reading up on  net flags and net lables so i will tidy things up this week and then post the circuit diagram.

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hi Created a diagram of sorts,drilling this down i twould like to join 3 separate matrices 2 by 12  by pigy backing the common anodes using idc cable cascade.  wires 1/2/3/4 to  shiftreg U12. the the cascade cable is cut at wires 5/6/7/8/9/10 wires 5 and 8 are for blue led go to SR U11 wires 6 and 9 are for green led go to  SR U10 wires 7 and 10 are for red leds  go to SR 09. 

below is a pic

Thankyou in advance or the helpi am being given

Schematic_rgb led common anode matrix 74hc595_2021-01-21_01-32-30.svg

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Still not totally easy to follow but I get more where you're coming from. I would prefer to draw it out as a logical table rather than a netlist. Are the LEDs on boards and you want to use DOUTX4 PCBs to drive them? Or are the shift registers also on your LED boards? 

4x source rows as selection pulses will work, though you get no faster multiplexing as that's limited to a doubled 4x pattern. But colours can only be 16 columns wide. 

If using DOUTs, you could buss two IDC10 ribbon cables and define them as one matrix but you still need a second DOUT to drive the 'second' matrix (third LED board). I would suggest simply to use 3x DOUTX4 boards and define three separate matrices with 4x source rows each. 

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Thankyou once again I will look into creating a logical table the LEDS are attached to boards as are the 10 pin headers. The board is an livid rgb omni board each board has two ten pin headers for controlling led feedback. http://wiki.lividinstruments.com/wiki/Omni_RGB. No shift registers on boards. I Was going to buss the boards together with an idc cable and then create one larger matrix using sparks fun type shiftreg break out boards then to a MIDIBOX DOUT BOARD.

as i have 4 positions free on SR u12 common anode columns  i thought i could connect a  second 72 led matrix into SR U12 via q4-q7

Really just trying to reduce the number of separate cables connecting things together As i have 9 rgb 10 pin headers in total to deal with.


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No problem, hope it's helpful!

You will need to figure out the wiring puzzle. The following links might be of use:

http://ucapps.de/midibox_ng_manual_ngc.html -> search "LED_MATRIX" and "DOUT_MATRIX"
There you can understand how things will look in software.



DOUT_MATRIX n=1  rows=4  inverted=0  sr_dout_sel1=1  sr_dout_r1=2  sr_dout_g1=3

This is an .NGC example of one four-row matrix. In theory you could share the same sr_dout_sel1=1, though you still need dedicated RGB columns. As you have common-anode LEDS:

inverted_sel=1 and (optionally) inverted_row=1

commands should be used when defining the matrix.


6 hours ago, doc.g4 said:

create one larger matrix using sparks fun type shiftreg break out boards then to a MIDIBOX DOUT BOARD.

This: https://www.sparkfun.com/products/10680 ?

You don't need that if you will use DOUTX4 PCBs. You can get creative with how you assemble IDC cables, no need to follow the original order or total number of conductors.


6 hours ago, doc.g4 said:

i thought i could connect a  second 72 led matrix into SR U12 via q4-q7

I guess you could consider defining an 8-row matrix?

If you save one shift register but give yourself a wiring headache, maybe the simpler approach is better. See ilmenator's approach for an 8x8 RGB matrix. 


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