compassdime

Compassdime is a term used for a coin-sized navigation device concept that combines a magnetic compass with a compact electronic readout to display a heading. The concept is mainly discussed in maker and educational communities and is not a widely established commercial product. It is often presented as a portable, pocket-friendly alternative to traditional compasses and as a hands-on tool for teaching magnetism and orientation.

In the typical envisioned design, compassdime is roughly the size of a small coin, about a dime in diameter. Inside, a magnetometer or Hall-effect sensor measures the magnetic field while a microcontroller processes the data and drives a tiny display or a set of LEDs to indicate the heading. Some concept sketches include tilt-compensation to maintain accuracy when the device is not perfectly level, as well as a calibration routine to address magnetic distortions from nearby ferrous objects or electronic equipment. Power is usually supplied by a small button cell or similarly compact battery.

Applications for compassdime ideas include educational demonstrations, quick-field orientation during outdoor activities, geocaching, and compact-scope projects for STEM learning. DIY versions typically rely on affordable microcontrollers and open-source firmware, allowing experimentation with sensor placement, calibration, and user interfaces.

Limitations of the concept include sensitivity to local magnetic interference, limited display readability on a coin-sized form factor, and the need for careful calibration to yield reliable headings. Because compassdime remains largely a prototype and educational concept, it has limited presence in mass production and consumer markets.

See also: compass, magnetometer, tilt-compensated compass, geocaching, orienteering.