For several years now, the tech industry has been pushing an IoT ecosystem in which everything is connected. You’ve seen this in the form of IoT smart outlets, light bulbs, thermostats, refrigerators, and pretty much every other product imaginable. While the chips that allow these devices to connect to your wireless network are very affordable, they still have a cost and require power. That makes them unsuitable for disposable or commodity products. That’s why researchers from the University of Washington developed special 3D-printable mechanisms that are able to transmit data wirelessly without any electronics at all, and they’ve made their designs available for you to experiment with.
Let’s say, for example, that you often forget to purchase a new bottle of laundry detergent when your old bottle runs low. It would be really convenient if the bottle of laundry detergent was capable of sending a signal to automatically order a new bottle when it is low. But adding traditional IoT electronics to the bottle to handle that functionality would cost a few dollars — increasing the cost of your laundry detergent by a significant amount. You would also have to deal with recycling those electronic components responsibly. The wireless transmitters presented here solve both problems by working entirely with plastic and can be 3D-printed or manufactured using more traditional processes.
These operate using WiFi backscatter technology, which has been around for a while, but has required electronic chips. This technology works by sending wireless signals out from a transmitter, such as a router, and then monitoring the reflected signals. In this case, the reflected signals are modulated by simple plastic mechanisms. The plastic is embedded with conductive material, like copper or graphene, which can reflect the wireless signals. Using clever mechanisms, the signals are modulated by physical motion. In this case of your detergent bottle, pouring detergent spins a wheel. As the wheel spins, modulated pulses are reflected back. This acts as a rudimentary flow meter that can provide enough data to deduce when the bottle is almost empty.
This flow meter is just one example among many similar mechanisms. The researchers also devised ways to transmit button presses, turning a knob, and even moving a slider that can be used for volume control. Springs can also be used to store data kinetically and then transmit them at a later time. We covered this technology a couple of years ago, but the research team has now made their 3D models publicly available. That means you can download the models and 3D-print them yourself to start experimenting with them. Utilizing the designs will require knowledge about WiFi backscatter technology, but their research paper goes into depth on the specifics of how it works.