Earbud-Size FM RADIO

In the June issue, the construction of a 'Miniature Watch-Style FM Radio' delivering stereo FM output was described.

- ASHWINI KUMAR SINHA

Building on that concept, the next objective was to create an even smaller FM radio compact enough to fit inside an earbud. However, the complete design proved too complex for a single article and is therefore being divided into parts.

This part, covering 'Earbud-size FM radio,' presents a simplified version—a basic FM radio embedded in an earbud with limited functionality. It allows listening to a single, preset FM channel configured on the main FM integrated circuit (IC). Alternatively, by presetting the IC to a specific frequency, the earbud can serve as a long-range FM spy device, receiving audio transmitted on that frequency.

The next part in this series of FM radio articles will introduce a tiny SMD-based microcontroller, such as the ATtiny85 or one of the world's smallest MCUs from Texas Instruments (like the MSPM0C1104: https://www.ti.com/product/MSPM0C1104?hqs = epd-msp-procbr-mspm0_small-pr-pf-ew25-wwe), enabling complete programmatic control of the FM radio.