The humble credit card reader — most of us have used hundreds, perhaps even thousands of them over the years. But even for folks like us, it’s not the sort of device we give a lot of thought to. It’s just a keypad, a display, and a magnetic stripe reader. How interesting could it possibly be?

That may be true in some cases, but at least for the 1990s-era TRANZ 330, there’s a bit more to the story than that. As [CharlesD] explains, these particular readers are essentially complete Z80 computers just waiting to do something more exciting than processing PINs. In the case of this particular unit, the addition of a GPS module and some new code has turned it into an interactive guide to the solar system.

Thanks to the UV erasable ROMs used in the TRANZ 330, loading new code on the device is easy enough. With a bit of educated poking around, [CharlesD] was able to map out what did what. Working from the basics of getting the display and keypad working, he moved onto the serial interface, which in turn let him communicate with a modern GPS module and era-appropriate thermal printer. From there it was just a matter of getting the math implemented to compute the azimuth and elevation of a given planet, and he had an offline map of the solar system for use with his telescope.

This is one of those projects which is awesome enough on its own merits, but it’s particularly exciting to see just how easy it is to repurpose one of these card readers, especially since [CharlesD] was kind enough to share his source code. If you end up picking one of these up and getting something running on it, be sure to let us know.

Although the demise of the Zilog Z80 processor has long been predicted, it would seem that this moment has finally arrived. The owner of the Zilog name – Littelfuse – recently sent out PCN ZAC26-0074, notifying customers that they will be taking final orders for the eZ80 and all other microcontroller lines that they currently own.

Over at Mouser, eZ80 parts have correspondingly all been marked as “End of Life”. This comes a few years after the original Z80 and its peripherals were discontinued, with the eZ80 still being an alternative until now.

Any potential sellers will have to put in their orders today, with orders still accepted until December 21 2026, with final deliveries taking place throughout 2027 as Littelfuse winds down its MCU manufacturing. This means that for commercial customers are least this is pretty much the end of the road for any circuit that still uses the eZ80 or similar.

Many of us have fondness for the Z80, which also has led to a potential way that the Z80 can live on. This includes both the many open source cores that are compatible with the Z80, as well as real silicon courtesy of the TinyTapeout project.

Thanks to [Techokami] for the tip.