BATTERYLESS MICROCONTROLLER Operation Using Supercapacitor

Imagine a world where microcontrollers (MCUs) and development boards operate without batteries.

- ASHWINI KUMAR SINHA

Energy-harvesting technology now makes this a practical reality. Several batteryless IoT sensors already capture power from ambient sources such as light, heat, vibration, and RF signals, enabling fully autonomous operation. Engineered for ultra-low-power performance, these devices typically consume only a few microamps to milliamps and employ multiple deep-sleep modes to maximise energy efficiency.

For prototyping, learning, or experimental work, engineers often need a general-purpose microcontroller rather than a specialised sensor. This design introduces a proof-of-concept system that demonstrates continuous operation of an MCU paired with an OLED display, entirely without a battery and without relying on sleep modes. Ambient energy is harvested, stored in a supercapacitor, and used to power both the MCU and the display continuously.

The system intentionally showcases a comparatively power-hungry configuration, including an always-active OLED display, yet still operates without a battery. During testing, the complete setup, comprising the MCU and OLED display with active processing, ran for up to five minutes on a single charge in normal operating mode.

When configured for ultra-low-power operation, the system continued to function for up to 25 minutes without an external power source, drawing only 6-7mA in total. Additional optimisation remains possible through more energy-efficient components, reduced display refresh rates, lower brightness levels, or improved duty-cycling techniques.

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