An 840 Segment Display

A while back, [limpfish] bought a few four-digit seven-segment displays from a seller on eBay. A month or two later, thirty displays ended up in [limpfish]’s mailbox. Instead of using the one or two displays he thought he ordered, [limpfish] decided to do something very cool with these bits of seven-segment displays. He’s controlling all of them at once.

[limpfish]’s usual method of controlling a lot of LEDs is the MAX7219 LED driver. This chip can easily — and cheaply — control eight common cathode seven segment displays. There’s a problem with this plan, though: the LEDs received from eBay are common anode. That’s actually not a problem, because with a little effort and even more thinking [limpfish] got these displays to work with the MAX7219 driver chip.

With chips in hand, [limpfish] designed a small breakout board for the MAX7219 and two common anode 4×7 segment displays. These displays can be daisy chained,¬†and connecting them all together results in a very weird but very cool visualization.

[limpfish] is treating this display as a bitmap display, which means it’s demo time. You can check out a 1337 01d skool¬†demo playing on this 840-segment display in the video below.

8 thoughts on “An 840 Segment Display

  1. Article says: “control eight common cathode seven segment displays”
    vs website: “Here’s my final setup controlling 8 common anode digits :”
    One display is four digits, so one chip can drive two displays but not eight.

    1. Eh? 7 segs are commonly produced in single or 4x packages. Both are displays. Just that one contains 4 digits the other 1 digit. Either way, a single max7219 can control 8 digits, either packaged in a single digit ‘display’ or packaged as 4x ‘display’.

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