Created by Skrekkøgle (Theo Tveterås and Lars Marcus Vedeler), Durr is a shivering unisex bracelet that investigates our perception of time by exploring how we perceive 5 minutes in different situations. By markedly shivering every 5 minutes, it creates a haptic rhythm to make us notice the changing tempo of time and become more aware of both actions we take and the time we spend on things.
Time perception is our subjective understanding of how fast time passes. Our ability to accurately estimate durations depend on a range of factors. With Durr you become aware of how your brain alters the length of a bus ride, how fast you finish a beer, how time flies by when you enjoy yourself, and drags along when you wait in line at the post office.
To design the bracelet, Theo and Lark kicked off with a few hundred iterations on the casing using their Makerbot for rough estimates on height and diameter. Same with the strap fasteners, they went back and forth on standard watch-fasteners, button studs and custom-designed friction-fasteners, settling with the self-made friction-fasteners. When it comes to the hardware, the process started with an old Arduino and a simple program that made a hooked up vibration motor go off every 5 minutes and they strapped it to their arms. Of course, Arduino was clunky to wear but they noticed that the perception of time did change. They bought a bunch of ATtiny45 and used Arduino to program it (see this tutorial on CAN). With some ad-hoc soldering, a Makerbot-printed casing and some electric tape they got something that wasn’t beautiful but of a more decent size. After some research, they figured out how to make the chip sleep for most of the time, only waking up once in a while to check if anything was happening, making it now last for two months on one CR2032 battery.
Now it was the time to get into PCB design and since neither Theo nor Lars had any experience, they started off with Fritzing. Once they got the PCB printed via EDA it did work but not as good as they wanted. So they redesigned the board, this time in Kicad, which was difficult to get the hang of but more accurate than Fritzing and ordered the PCBs from OSHpark. Unfortunately the PCBs were still too tall for their preferred design, they once again redesigned the board to use a few SMD components. They printed the final PCBs with Seeed studio, both because they had black finish available, gold-plated ENIG pads and really thin boards. Soldering pieces together was a challenge especially since some components were super small but they managed, soldering all 50 boards in triplets.
The project is an internal experiment as a test to see if more people are interested. They have made only 50 of these, as a limited alpha run. It comes with a replaceable battery that lasts up to two months. You can order yours from their store for €90.00 and choose from 5 different colours.