This project is a hardware electronics experiment where a standard calculator enclosure is modified to house a custom microcontroller-based system.
The original calculator LCD is removed and replaced the solar panel with a 128×32 OLED display, interfaced via I2C with a Wemos D1 Mini (ESP8266). User input is handled using three tactile push buttons salvaged from an old blood pressure monitor.
To fit the additional electronics, minor internal plastic sections of the calculator casing were trimmed. This project represents the first functional prototype and serves as a proof of concept.
- Wemos D1 Mini (ESP8266)
- 128×32 OLED Display (I2C)
- Three tactile push buttons
- Modified calculator enclosure
- Jumper wires for temporary power
The internal schematic and wiring layout of the modified calculator is shown below.
Chosen for its compact form factor, low power consumption, and simple I2C interface.
Buttons were scavenged from an old blood pressure monitor to reduce cost and encourage component reuse. Standard tactile push buttons mounted on a zero PCB can also be used as an alternative.
Small internal plastic structures were carefully removed to create sufficient space for the OLED display and microcontroller.
The current prototype is powered using external wired connections.
- Integration of a compact battery
- Estimated battery backup of approximately two hours
Internal wiring and layout images are provided in the repository for reference.
- First iteration complete
- Battery integration planned
- Further layout and power optimizations pending