Perhaps we take for granted digital methods of transmitting information, but have you ever considered using chemistry to convey a message? A previous entry in this blog featured a device developed by George Whitesides’ group from Harvard University, US, which used fuses dotted with alkali metal salts to generate coloured flames, where different sequences of colours are assigned to letter and numbers.
The latest wacky scheme to emerge from this group uses droplets of liquid as the data source.
The device shines light through an optical mask, basically a sheet with clear or coloured windows, to a channel with a flow of transparent droplets suspended in black ink. Finally there comes an appliance to collect and measure the light that makes it to the other side, either a spectrometer or video camera, while computation is needed to decode the signal. Hence light passes through when a droplet is adjacent to a window in the optical mask.
An interesting feature is that multiple properties of light, such as intensity, wavelength and polarisation can be recorded. This makes the data intrinsically more complex than binary systems comprising bits with a value of either 0 or 1. Light with differing intensity can be generated using windows of varying size in the optical mask. Wavelength and polarisation can be altered with coloured windows in the optical mask or polarising filters respectively.
Undeniably inventive, clever and pretty, but what are the potential applications? The group foresee operation in environments where electricity is either hazardous or unavailable, including chemical or molecular computing. Before that though, technological developments are required, to provide detectors, pumps etc which function without electricity. Judging by the video it could also be perfect to communicate a secret message during a display of Christmas lights.