In the world of wearables, smaller components are better. Smaller means things are easier to transport and more comfortable to wear against your body. Michael Yang, co-creator of KeKePad and a Maker with an interest in smart clothing, discovered this for himself when he started making his own wearables in 2014.
Although Yang liked the Arduino Lilypad, he found using conductive thread frustrating. “Using conductive thread as the wires in electronics is a fresh idea, but there are some obvious drawbacks,” Yang explained. He sees three main problems with conductive thread: It has no insulation so it requires Makers to sew creatively to avoid short circuits; using a needle with the conductive thread can noticeably break up the fabric; and for a really tight connection to the board, wires would need to be soldered, but doing this means that the board could not be easily removed if there were any mistakes.
KeKePad is an attempt to address all of these issues. The KeKePad itself is an Arduino compatible platform with a series of sewable modules designed to be as small as possible and to connect together with special cables (Ke Cables) that have crimp terminals. Modules include sensors for detecting light, sound, temperature, humidity, and acceleration, as well as actuator modules for things like LEDs, and vibrating buzzers.
The Ke Cable itself is the key feature of this platform. Yang and his team spent months finding the right wire and insulator combination that would work for this ultra thin 3-pin cable. The drawing room floor of their workspace is littered (metaphorically speaking) with “thin flat cables,” IDC cables, FFC cables, ultra soft silicone wires, and even enamelled copper wires, none of which met the requirements.
The resulting Ke Cable is thin, but strong and flexible. According to Yang, it’s the thinnest cable with crimp terminals in the world. The wire is Teflon coated copper wire AWG34, with a diameter of only 0.32mm and very low resistance. The crimp terminals mean that you don’t need to solder to ensure a solid, but easy-to-remove connection. The insulation prevents short circuiting, and because it’s a 3-pin cable you won’t need to plan the wires out as carefully as you might with conductive thread.
The cable itself is not designed to be threaded through the fabric, but could be fixed in place (if that’s desired) with a couching stitch. Also, due to the extreme thinness of the wires, they can’t be manually stripped (in production, they’re stripped with lasers), so cutting them down to size won’t be possible. Currently, they are only available in 100mm and 250mm lengths, although KeKePad has a tiny cable extender so two cables can be connected.
Even with these considerations, the KeKePad as a platform seems like a step in the right direction for wearable components, at least in terms of size and ease of use. These products are not available to purchase just yet, but Yang says they’ll be available after a crowdfunding campaign geared at increasing their publicity. (Update: KeKePad has now launched an Indiegogo campaign for those interested in backing their project.)
Do you make wearables? Let us know in the comments below whether or not you think this would be a marked improvement over conductive thread.