I'm making an 8x16 LED matrix display using 3 shift registers, 8 0.1k registers (used in rows), and an Arduino nano.
The display text is scrolling fine but the issue is Can't identify the Letters. Actually, the issue is, when a LED turnOn its left and right LED also Turning On (with low brightness). In the video, the text is **ABCD I **. letters are using single line and column off led. But all are looking like rectangles.
I have seen many tutorials on YouTube and other sites. And use their code, but always I got the same issue. Can anyone help me, please?
At this post, I was given the wrong sample youtube video link. Now I have corrected it (in the video description also has the code link). You can recheck please
OK, now just some hardware comments: You indicate 220 Ohm resistors for the anode drives - but then suggest using 100 Ohms. If you are gong to use 74HC595s for the cathodes, you need to use 1k resistors for the anodes.
If you want to use 220 Ohm resistors, you need to use TPIC6B595s for the cathode drivers.
For an 8 by 16 matrix, the proper way to drive it is to use two MAX7219 chips.
As always, I recommend buying one of the MAX7219 matrix module kits, unassembled like this:
Better still buy a couple, assemble one with the matrix provided for practice, and wire the other one to your own array.
The point is that you do not install the matrix arrays from the kits themselves - or their socket pins, but just solder to the positions on the PCB and you have a durable and reliable assembly to drive your own matrix arrays or in this case, seven-segment displays in custom mounting.
Why did I say two or three? Well, you can fully assemble the first one as the matrix with which it comes and practice programming it. Then the second one for your current project and the third one - for the next! :smiley-lol:
Bro! I actually used 100Ohm resistors (in diagram I mistakenly used 220Ohm. Cz of mistake was I haven't find 100Ohm in Fritzing).
Bro! If I i use 1k resistors. The problem will be solve?.
Also, In some video I have seen they are used Transistor in every row. For example In this video. I know transistor work like a switch. But why used Transistor instead of connect directly?
No, I was pointing out a hardware problem - the 74HC595 driving the common cathodes is not rated to sink the current of eight LEDs at once, so you need to limit the current to each anode so it totals no more than 35 mA for all eight. Nevertheless they will probably survive with the wrong resistor values.
Or in this case, the columns. Using transistors allows you to sink the current from all eight anodes at 20 mA simultaneously as the (appropriate) transistors can easily sink 160 mA with less voltage drop than the 74HC595 at 35 mA.
But as I said, the proper way, is to use the proper driver IC.
My advice relates to the hardware matters - whether you are likely to damage the ICs and experience premature failure. I have not looked into your (presumably) software/ code problems. In any case you have not posted (using the forum instructions) your code for me to look at.
Hi @riz1ahmed, I think there is a problem with the latch of the row driving shift register. Please check if there is any short to another pin. Is it connected correct? Is the pin of the Arduino still working?
