Integrating 3D printed circuitry into a 3D printed object is a breakthrough idea being developed by a number of well-funded companies that would create a revolution in custom electronic devices. Printing circuitry could allow for the additive manufacturing of just about any electronic device (robots, radios, computers, etc..) and new devices that have yet to be imagined.

Due to the technical complexity involved, one may assume that the capability to 3D print circuits would be out of reach for the owners of desktop 3D printers. Of course, since nothing seems to be impossible in this growing age of additive innovation, the 3D printing of electronics is now coming to the masses thanks to a small group of Stanford students and their Rabbit Proto conductive ink extruder.

The Rabbit Proto team of Alexandre Jais, Manal Dia, and Rohan Maheshwari, have invented an extruder head add-on that is basically a nozzle that emits a conductive ink. With the Rabbit Proto extruder makers of all levels can create 3D printed objects, with integrated circuits, using an affordable desktop 3D printer.

The Rabbit Prototyping system is ideal for entrepreneurs who need to launch a working prototype quickly. Manal Dia, the operations wizard of the group, estimates that Rabbit Proto will be able to go from zero to revenue in 10 weeks.

The Rabbit Proto web site explains it as follows: "Unlike some of the 2D circuit printers out there, Rabbit Proto allows you to effortlessly print circuits inside of the plastic design itself – without having to interrupt the printing process. You can also print circuits on 3D surfaces, and can deposit some pretty complicated conductive patterns while doing it."

Rabbit Proto can print a first part of a plastic enclosure, then deposit a conductive pattern, and finally finish up printing the rest of the plastic enclosure – all in one printing process.

An example of a prototype created with the Rabbit Proto is a puzzle with integrated circuits that will light up when all the pieces are connected.

The Rabbit Proto extruder is now available for pre-order and comes in 3 flavors: the single conductive ink extruder, a combination filament/conductive ink extruder, and a complete Rabbit 3D Printer for those who want a ready-to-go machine with minimal calibration.

As an open source project the Rabbit Proto team hopes to attract developers who may add functionality to it in the future. The  Rabbit Proto firmware is available on Github with a number of demo projects, such as a game controller and an iPhone stylus.