Virtual ADAM Disk Drive - Prototype

The pre-production prototype of the MicroFox Virtual ADAM Disk Drive, dated © 2014 on the PCB silkscreen — two years before the 2016 commercial release. Signed and attributed by designers Bob and Doug Slopsema of MicroFox Technologies on the acrylic enclosure. This is a three-board sandwich assembly in a clear acrylic prototype case, revealing the full development architecture before it was consolidated into the production unit.

The prototype is built around an Arduino Mega 2560 (ATmega2560 @ 16MHz) as the ADAMnet protocol engine, paired with a custom MicroFox-designed green PCB that provides the ADAMnet bus interface, a 2×16 HD44780 character LCD (blue backlight), a microSD card slot, three navigation buttons (PREV / SELECT / NEXT) for disk image selection, and dedicated ADAMNET IN / ADAMNET OUT RJ connectors for daisy-chaining. A third sub-board handles DC power regulation. Hand-wired purple jumpers interconnect the custom board to the Arduino, characteristic of first-article prototype development. A bodge wire on the PCB indicates at least one routing correction was made post-fabrication.

The ATmega2560's hardware UART handles the ADAMnet slave protocol at 62,500 baud via an open-collector buffer stage on the custom board. SPI on the same processor drives the microSD card. This architecture — AVR microcontroller implementing full ADAMnet timing in firmware — was validated in this prototype and carried forward to the production design, and later influenced subsequent ADAMnet emulator projects in the ADAM community.