Let's build your own designs on flexible circuit boards

The advent of micro controller modules like the Arduino opened up ability to build and program interactive objects to a whole generation of makers. Today these modules make it simple to control everything from DIY robots to remote control door bells. This learning tool is supported by add on modules known as shields that include displays and drivers, motor drivers, sensors, and communications units. These are all pretty much plug-and-play, and with the support of an ever growing software library have opened new possibilities for makers and innovators to test their ideas. Some platforms, such as Printoo, have embraced flexible electronics which does literally add a new dimension to projects – they no longer need to be flat two dimensional objects. Enter affordable 3D printing and the threshold to developing innovative, interactive ideas just got lowered further. But what do you do when there is no standard module to perform the function you need?

Step 1: BYOD – Build Your Own Device

The answer is simple – make your own. Inexpensive flexible PCB prototypes are one of the key elements in this process and a perfect complement to 3D designs. CIT Technology have worked with designers, makers, and innovators of all levels of expertise to help bring their ideas to life. Everything from touch buttons, sliders, LEDs, speakers, and sensors have been printed onto low cost flexible PET substrates.

Bluetooth enabled "Smart Inhaler" circuit tracks usage

Printing flexible PCBs is now an accessible, low-cost option for the DIY maker. The technology has been developed for over a decade, and with digitally printed flexible circuits now a reality, professional quality flexible PCBs are affordable options not just for professional developers but also the hobbyist. These boards offer repeatable quality and predictable conductivity and can also be the first step on the ladder to scaling to production if that is the goal.

In order to save time, developers can use multi-approach prototyping; in other words, produce a number of variations on a design and evaluate which performs best – a Darwinian approach. Designers can take advantage of the fact that digitally printed flexible printed circuits are produced using a continuous reel-to-reel process directly from the design files. Therefore, it is just as simple and economical to print ten different designs as it is to print ten of the same design.

Flexible LED array can be wrapped around curved surfaces

Step 2: Flexible can be flat too

Flexible circuits don’t always have to flex; they are often bonded to something rigid. They can also ‘flex to fit’, conforming to a curved design. Designers can fold and shape their circuits into complex forms and, for example, create battery contacts, curved sliders, and buttons or LED indicators around shaped objects.

Bluetooth sensor circuit: This is folded into shape and over-moulded with plastic.

Where devices have complex shapes, the electronics would traditionally have be spread across several conventional flat circuit boards requiring connecters and wiring looms to join them. With digitally printed flexible circuits, the inherent flexibility and the low cost of real-estate allows the designer to combine the functions of several boards onto one single interconnected circuit.  Microprocessors, wireless comms, capacitive touch elements, LED indicators, sensors, and sounders can all be built onto the same circuit and distributed around complex 3D objects without the need of connectors and labour-intensive wiring.

Test patterns for flexible heater elements

CIT have extended their PCB prototype service to include a choice of substrate materials previously only available for higher volume manufacturing. These include optically clear and heat stabilised films. These films are particularly effective for creating capacitive touch controls which can be back-lit and can incorporate controls, LEDs, and other electronics, all on a single circuit. Flex allows you to think and build in 3D – so get creative!