A Modular Computer That's Bringing Back Analog

Digital computers may have won out over analog, but that doesn’t mean analog has lost its relevance. While digital systems dominate today due to their precision, ease of storage, and noise immunity, some problems are better suited to analog computations. Differential equations, for instance, which are important to many applications in engineering, physics, economics, and biology, can often be solved more efficiently by analog systems.

A modular analog computer called CONTINUUM, developed by Marco Monzani, has just been released for people who would like to experiment with the technology. Unlike traditional analog computers — large machines with fixed internal components — CONTINUUM adopts a modular design. Each computational element exists as a separate circuit board roughly 60 by 40 millimeters in size, allowing users to build systems piece by piece.

The boards can be connected using simple wires and are held in place with magnetic pads, enabling them to be arranged on a magnetic whiteboard or metal plate. This layout not only keeps the system flexible but also allows users to label variables and equations directly on the board while working.

Classic analog computers were powerful but expensive and limited in scalability. By separating each functional block into its own module, Monzani aims to reduce the barrier to entry. Users can start with only a few modules and expand their system as their projects grow in complexity. If a module fails, it can be replaced individually without affecting the rest of the system.

Each module corresponds directly to a mathematical operation used in differential equations. Core components include integrators, summing amplifiers, multipliers, and coefficient controls implemented with potentiometers. These blocks can be wired together to represent equations in hardware. For example, a harmonic oscillator — derived from Newton’s second law and Hooke’s law — can be built using two integrators and a feedback loop. Initial conditions, such as the amplitude of oscillation, are set by adjusting a potentiometer that initializes one of the integrators.

In operation, variables are represented as voltages, typically within a ±10-volt range supplied by a ±12-volt power system. Because all modules operate simultaneously, the solution to an equation evolves continuously in real time. Results can be observed directly with a voltmeter or, more commonly, with an oscilloscope to visualize how variables change over time or interact in XY plots.

The system also includes a master control module that distributes power and provides synchronization signals to start, pause, and reset computations. This allows integrators to be reinitialized for repeated runs, a useful feature when studying how parameter changes affect system behavior.

CONTINUUM is now available on Kickstarter, with rewards ranging from $70 for a basic starter kit to $196 for a complete kit.