Angel Cabello's Galdeano Handheld Is a Pocket MicroPython Calculator with Hidden Capabilities

Designed after dissatisfaction with commercial calculators, this Espressif ESP32-powered handheld has secrets to share.

Maker and calculator enthusiast Angel Cabello, finding nothing on the market to fully scratch his itch, has designed his own surprisingly powerful pocket calculator — which can double as a portable computing machine for a range of tasks, including acting as an Internet of Things (IoT) control system.

"I fell in love with calculators," Cabello explains of the project's origins, "but no one was good enough, so I created my version. [Galdeano Handheld] is a DIY graphics calculator, with a CAS [Computer Algebra System], an algebraic mathematical engine, so you can use it to integrate, derivate, and do matrix calculations. But if you dig into it a little, you will find an [Espressif] ESP32, with Bluetooth and Wi-Fi connection."

The Galdeano Handheld is a kit-form calculator which offers everything you'd need and a lot more besides. (📹: Angel Cabello)

Designed to mimic the appearance of classic graphing calculators, the heart of the Galdeano is an Espressif ESP32 microcontroller module running a customized MicroPython firmware. On this, Cabello has created an LVGL-based graphical user interface for local use – displaying on a color LCD panel at the top of the calculator and taking input from a tactile button matrix taking up the bulk of its face.

Powered by two AA batteries in its latest incarnation, the calculator can be used as-is for a range of mathematical functions. Peer under the surface, though, and it is in effect a microcontroller-driven pocket computer complete with Bluetooth and Wi-Fi connectivity: Cabello has used the device to control a smart lighting system, as but one example of why it's better than anything you'd find on a store shelf.

Cabello is selling the Galdeano Handheld on Tindie at $170 plus shipping; the modified MicroPython source code is published to GitHub under the permissive MIT license with additional code available in a separate repository under the GNU General Public License 3.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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