Guess you’re right, but where to buy them? Previously I bought some MSGEQ7 on aliexpress and I was kinda disappointed (they didn’t work at all from two different sellers). Are there any “clone” sellers that are worth my money?
Well, the MSGEQ7 is nowhere near as popular with experimenters as the MAX7219s and I have certainly not pursued them.
The problem here is this:
I got a small 7 segments display that can display 3 digits.
This is a sort of “cart before the horse” problem.
Although her prices have recently inflated substantially for what is probably a fairly obvious reason and she frequently posts bogus “auctions” (there is one at the moment!), most here have generally found “Alice” reliable. buying a MAX7219 to match a display you already have is just not sensible! Essentially, you have an orphan part.
If you want a display, this is what you buy:
There! It’s done!
Before the postage charge appeared, it was just US$1.85 shipped to your mailbox. There are other versions of this module, but if you only want four digits, you just pull off the second display because they are socketed - it makes no difference to the operation and you code it for only the four digits you want. If you only want three digits, just mask off the fourth but seriously, you don’t only want three digits, do you? In fact, I doubt you would say “no” to eight digits; you can have a lot of fun with that.
There are other, smaller four digit modules, equally cheap, some configured as a clock display, using the TM1637 and requiring two dedicated pins to control so if that is what you want, search on TM1637 (or here it is for you! ). Either way, you do not sensibly build a display; you just buy it.