Widget of the Week #4: 8 x 7-segment display MAX7219

A quick one this week after last week’s marathon.

Projects often need a few digits of numeric display – from thermometers to clocks these eight digit displays are a cheap and easy-to-use solution.  Commonly known as MAX7219 but that doesn’t refer to the display at all but the multiplexer chip that drives the LEDs from a serial input.  It’s also found in 8×8 matrix displays that we’ll come back to in another WotW.

At a current price of around a pound you can pair one with a NodeMCU to make an NTP synchronised clock accurate to fractions of a second for under a fiver.

While this display has decimal points it lacks the colons necessary for a nice looking clock so we’ll look at other displays in a future post.

We’re compiling reference information in the wiki over at http://wiki.wlhs.co.uk/index.php/Ref:_MAX7219_8_x_7-segment_display