CalcOpen

devlog — open source $25 graphing calculator

2026-05-12

Day 2: PCB design

Since the parts have no been deliverd yet, I started working on a first pcb design based off the figma design I made yesterday in a new folder called hardware. This is my first time making a PCB so I can only imagine some things are off. It was preety fun though. I'm excited to get to working on the physical hardwarre but it still hasn't come so trying to do what I can in the meantime.

Parts still waiting to arrive... my dorm package prossessing sucks.

Ok so the PCB I made sucks and I could't even finish wireing it but it was a good first go.

Made a second version of the PCB and honestly it's not much better but im bored so.

2026-05-11

Day 1: The Start

ESP-IDF is now fully setup to build and flash blinky utilizing the onboard led on the esp32 model I purchased. To build idf.py build and to flash I belive it's idf.py flash, but only time will tell. I also finsihed and uploaded the first iteration of the button layout to docs/designs which was made using Figma.

Parts will arrive tommrow so testing and the code base will start to form.

2026-05-07

Day 0: why?

A TI-84 costs $130 and runs a Z80 from 1976 (even the neweer mdoels are slower than they should be for this price). OpenCalc is the same thing for $25 — ESP32-S3, color LCD, USB-C, computer emulation, and MicroPython scripting built in. It's quite frankly ridiculous to be expected to spend $130 on a calculator with a processor that's older than most people using it.

Everything open source. This log tracks the build from scratch.

Today I made a planning document, started this blog, orderd a board, screen, some buttons and some wires, and setup the enviorment I'll be using, ESP-IDF. Everything ready to start just waiting on physical componets now.


MIT · github