I picked up a dozen small dot matrix displays from a surplus place about ten years ago.  At the time, they were very cheap (maybe 10/$5?).  Now I wish I’d grabbed more. I’d really like to make a wristwatch out of these.  Let’s not get ahead of ourselves.  The logic and power requirements of these things aren’t trivial. They appear to be HDSP-2000 series displays made by HP/Avago.  They are “dumb” displays in that they don’t incorporate any kind of character encoding.  They are just the matrices and a shift register. This application note shows how to hook them up.  It looks like an external constant current source capable of 110mA per channel per character is required to drive the columns.  The application note suggests UCN5890A but is a bit hard to find.  MIC5891 is roughly equivalent, easy to find, and will source 500mA per channel.

I picked up a dozen small dot matrix displays from a surplus place about ten years ago.  At the time, they were very cheap (maybe 10/$5?).  Now I wish I’d grabbed more.

I’d really like to make a wristwatch out of these.  Let’s not get ahead of ourselves.  The logic and power requirements of these things aren’t trivial.

They appear to be HDSP-2000 series displays made by HP/Avago.  They are “dumb” displays in that they don’t incorporate any kind of character encoding.  They are just the matrices and a shift register.

This application note shows how to hook them up.  It looks like an external constant current source capable of 110mA per channel per character is required to drive the columns.  The application note suggests UCN5890A but is a bit hard to find.  MIC5891 is roughly equivalent, easy to find, and will source 500mA per channel.

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