AITRIP 5 PCS 8 Digit 7 Segment Module MAX7219 8 Bit Digital Segment Tube LED Display Module Compatible with Arduino MCU/51/AVR/STM32/Raspberry Pi 4 Model B

They have a voltage out in addition to a voltage in, and by design, you should be able to daisy chain up to 8 of them. But they just require too much current at 5v to power them in series. The second and third ones in the chain glitch out, and the fourth one doesn't even light up. Running them at a lower voltage, like 3.8 or 4V, improves this slightly. Powering them in parallel solves the problem altogether. Running the CLK, DATA, and CS pins in series works just fine.

As another review points out, i too received Unmarked chips! Some are, some are not. They are supposed to be MAX7219's but we'll never know because all 5 tested bad! They were setup on breadboard next to a 5digit 7seg set i bought from PropWash for flight sim, and side by side, swapping output files in MobiFlight, 2 of them litup at startup, but never display any digits. Are they banking on the fact that people just wont return these? What a ripoff.Junk, absolutely junk!

One arrived only half soldered. How did this ever pass qc? Lol see also the title.

Does not work. Other than that, they're great! Lol. You will see some red light. You will not see the numbers you're trying to display. I've verified this side by side with the same product from another seller. The other seller's product works. This one behaves erratically and illuminates random segments. This seller does not deserve your money. Don't give it to them. Returning. Absolute trash. Waste of time and money.

These arrived on time and all seem to work perfectly.