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What Peter Balch’s Solve calculator does
Solve is both a pocket calculator and a numerical equation solver. Balch describes entering several equations in any order, including nonlinear and simultaneous equations. For-loop constructs can also generate a table of answers or plot a graph. The project’s own description is that it can be used “as an ordinary pocket calculator.”
In a Hackster feature by Gareth Halfacree, Balch describes its central function as: “The Solve pocket calculator solves equations numerically.” The project materials also include help pages with runnable examples, according to that feature. They do not establish a complete syntax reference or specify precision, speed, error handling, or the exact mathematical limits of the solver; those capabilities should not be assumed.
Hardware in the documented build
The project is a DIY build, not evidence of a finished calculator sold as a retail product. Its core is an ESP32-WROOM-32 module paired with a color TFT and a custom physical keypad. The project page lists these main components:
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- One ESP32-WROOM-32 module. Balch says he used a 30-pin version; other pin-count versions exist.
- One 2.4-inch, 240×320 ILI9341 SPI TFT display.
- Twenty-eight miniature push-button switches for the keypad.
- A lithium cell and USB lithium charger module for the rechargeable arrangement.
Hackster reports the display as 320×240 pixels and describes the buttons mounted on stripboard. Balch also describes an alternative power arrangement using three AA or AAA cells in a holder. The enclosure is custom 3D-printed, shaped to angle the display and keyboard. The project page provides wiring and build guidance without a dedicated main PCB.
These are project-specific component notes, not general electrical safety instructions. Before assembling a battery-powered version, check the relevant manufacturer documentation for the module, display, charger, cell, and regulator limits, and verify that the selected parts are compatible.
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Why the software has a 40-year history
The age claim describes the calculator software’s lineage. Balch says he began the first version in BASIC on a Sharp Pocket Computer roughly four decades ago. In the intervening years, he rewrote it in Turbo Pascal, Delphi-1, Delphi-4, and then C for the current project, which is described as an Arduino implementation.
“I wrote the first version of this software in BASIC on a Sharp Pocket Computer around 40 years ago.”
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That recollection is Balch’s account, reproduced in Halfacree’s Hackster feature; it is not a measured age for the current hardware. The present build uses an ESP32-WROOM-32, a much later microcontroller platform.
How to approach the build
For someone interested in building Peter Balch’s Solve calculator, the project page is the practical starting point: it lists the components and provides software and build guidance, including 3D-print files. Expect a hands-on electronics project involving a custom keypad, display, wiring, power arrangement, enclosure, and software—not a ready-to-use appliance.
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- 3 sets of code: MicroPython, C and Processing (Java). Python is one of the most popular languages, and C is one of the most classic languages. Processing code needs to run on computers to provide graphical interfaces
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- Review the project’s component list and build notes at Peter Balch’s Solve pocket calculator project page.
- Check that the ESP32 module’s pinout and the chosen TFT, switches, charger, and battery match the documented design before ordering or wiring parts.
- Follow the project’s wiring and software guidance, and verify power and charging limits against the component manufacturers’ documentation.
- Use the project’s enclosure files if you want the angled, 3D-printed case; the enclosure is part of the DIY build rather than a separately established retail accessory.
The project page was created on October 14, 2024. Component availability and file availability can change, so consult the live project page for its current materials rather than assuming a particular part or download remains available.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Who Solve is for
Solve is most relevant to makers who want a calculator they can assemble and inspect, or who are curious about numerical equation solving on a small embedded device. Its ordinary-calculator role may make the interface useful beyond solving equations, but the available project descriptions do not document every supported operation or make a direct performance comparison with commercial scientific calculators.
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It is less suitable for someone seeking a finished calculator to buy, a verified substitute for a particular scientific or graphing calculator, or a solver with documented guarantees about precision and supported mathematical cases. Those details are not established by the project descriptions cited here.
Quick Recap
Project sources
- Peter Balch’s Solve pocket calculator project page — project components, build notes, and software materials.
- Gareth Halfacree’s Hackster feature on Solve — calculator description, reported display and keypad details, and Balch’s attributed account of the software history.
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