HP-1973

We're used to thinking of emulation in terms of old games consoles or arcade machines, but there's also a thriving community of enthusiasts for old digital calculators. Their enthusiasm is there for many of the same reasons, too: a mixture of nostalgia, functionality, and modern capability that makes revisiting old hardware fulfilling in ways not possible earlier. One of the best examples of this is a software recreation of the HP-45 scientific calculator, called HP-1973. The HP-45 was launched in 1973 and was Hewlett Packard's second-ever scientific pocket calculator, and their successor to the first, the HP-35. Both had distinctively square and diminutive seven-segment displays and offered various trigonometric functions alongside basic calculator functionality, with the latter adding nine storage registers, a four-level stack, and a Shift key for accessing many more options from the same keys.

All of this has been recreated in HP-1973, a graphical desktop application that will run wherever Python 3 is installed. It recreates all the original features from the included ROM image and boasts both a realistic red simulation of the screen and image-driven button inputs, complete with shift functions. Most importantly, function of the original device has been expanded with introspection and monitoring tools to give you a peek at what's happening inside the calculator. The output display includes a map of the ROM data, the four-level stack, the internal register values, and a decompiled execution list. You can even interact with the decompiled execution list just as you might a debugger, with options to jump through the code and change values. It's a wonderful way to see what was happening within the black plastic case of the original as you fight with the input Reverse Polish notation, where operators follow their operands, to generate output.

Project Website

https://sarahkmarr.com/retrohp1973.html

Grab a copy of the original manual and spend a rainy afternoon learning the ins and outs of the world's second pocket scientific calculator.

Piano plugin

Piano Forte

Despite a lack of professional musicians, Linux has become a wonderful platform for inventive music and sound processing, as well as professional-quality effects and plugins. One of the best of these is the commercial and proprietary Pianoteq. Pianoteq is a virtual piano that produces stunning results, not from audio recorded samples of a real piano, but from its own mathematical models of how a piano works. It calculates the audio energy and pressure from how a piano's hammers physically excite each string, how each string resonates with the others, and how everything resonates within the frame and its case. Thanks to the way everything interacts within the model, nothing quite compares to the sound Pianoteq can generate, which can be either exactly like a specific piano model, or tweaked and reprogrammed into a purely fictional instrument.

The Piano Forte Audio Plugin takes a very similar approach to generating piano-like sounds, and it has the distinct advantage of being open source. It's still at an early stage, but it can already generate a decent piano sound that is better than a simple SoundFont and can sound more natural to play. Like Pianoteq, the sound is entirely generated by algorithms, but unlike Pianoteq, the algorithms have been built with machine learning, using a neural network that's been trained to produce a piano-like sound. The size of the neural network is tiny compared to some of the numbers we're now used to hearing, just 8KB in size with 1,500 parameters, but it has at least been trained with freely available piano sample sets. Building an instrument like this is utterly unique. What's perhaps more interesting is that the same technique could be used to replicate all kinds of sounds, or even open up a new kind of synthesis, and it's wonderful that this technology is open source.

Project Website

https://github.com/tesserato/PianoForte

Piano Forte sounds more like an electric piano than a real piano, but it's still a great achievement.