Researchers at Worcester Polytechnic Institute, Imperial College London, and University of Illinois Urbana Champaign have recently developed a new robotic system that can visually rearrange its surroundings to receive the maximum amount of energy from a given power source.

Although powerful design software and cheap manufacturing services have made rolling your own PCBs easier than ever, there are some situations where a piece of FR-4 just doesn’t cut it: think art projects with hidden LEDs or biomedical applications that need to attach to the human body. For such occasions, [Narjes Pourjafarian] and her team at Saarland University in Germany developed Print-a-Sketch: a handheld device that lets you print electric circuits on almost any surface using conductive ink.

The heart of the device is a piezoelectric print head, as used in some types of inkjet printer. It dispenses tiny droplets of silver nanoparticle ink, which is conductive enough to make useful electronic circuits by simply printing a schematic. Lines can be drawn to connect components, while customized footprints can hold LEDs, capacitors or even integrated circuits.

Print-A-Sketch: A Handheld Printer for Physical Sketching of
Circuits and Sensors on Everyday Surfaces
https://narges-pourjafarian.github.io/assets/img/Print_A_Sketch.pdf

I used ELECTROLUBE brand conductive paint that came in small bottle. It had been on my storage cabinet for many years and was still useful while by newer conductive ink pens had dried out.

https://www.youtube.com/watch?v=FAC3kqzWm4g

You can actually make an approximation of this just using an ultrasonic cleaner and silver gilding foil, with the particles dried and mixed with “Humbrol Liquid Poly”. Worked for me though not as good as this: conductivity was about 1/10 that of store bought silver demister paint and it wasn’t compatible with as many materials. Someone should try this with some of the tiny RGB LEDs with dual data lines and make a mask.

Spurred by the growth of low-cost, additive 3D- printing, conductive inks have regained attention in recent years despite having existed for quite some time. A 10-year forecast conducted by IDTechEx suggests that the conductive ink market will reach $400 million over the next decade.

According to the report, “Printed large-area piezoresistive, capacitive and biosensors are set to become one of the largest constituents of the greater printed electronics industry.”