World’s first wireless molecular network uses rubbing alcohol to send text messages

Molecular communication, sprayer

Researchers in the UK and Canada have succeeded in creating the world’s first text message via a molecular communication. The messages are encoded in molecules of alcohol, which are then wafted across the room to a receiver, which sniffs the molecules out of the air and decodes the message. Molecular networks are an area of interest for applications and environments where the usual method of wireless communication — electromagnetic radiation — can’t be used, such as underwater, underground, in oil pipelines, or inside your body.

The molecular communication setup, created by the University of Warwick in the UK and York University in Canada, is surprisingly simple. There’s a commercial electrical sprayer (DuroBlast) that transmits the signal, and on the other side of the room there three alcohol sensors (MQ303, MQ-3, MR513) attached to an Arduino microcontroller that receive the signal. The transmitted message is encoded by another Arduino, which is connected to a custom switch that’s wired up to the electrical sprayer. Each letter of the message is encoded as binary, which is then translated into sprays. There is a fan behind the sprayer to help the molecular signal across the room.

(The video says that vodka is used as the molecular messenger, but that’s a lie designed to make the research sound sexier than it actually is. They actually use isopropyl alcohol — rubbing alcohol… which, while it might look like vodka, you really shouldn’t drink it.)

The molecular signals are encoded in terms of concentration, with a binary 1 being represented by an increase of alcohol concentration, and binary 0 being a decrease. In turn, this means that one pulse of the spray equates to a 1, while not spraying is a 0. This is a simplistic version of how molecular communication works in the plant and animal kingdoms — there is now fairly definitive proof that plants communicate with other by releasing chemicals into the air, and animals, as you know, are all about pheromones.

Molecular communication transmitter

The transmission side of the molecular communication setup

The three different alcohol sensors

The three different alcohol sensors, detecting alcohol at 2 meters (left) and 4 meters (right)

Despite the simplicity of the system, text messages can be reliably transmitted up to a distance of four meters (13 feet) — but the transmission rate, which is around 0.2 bits per second, is incredibly low. 0.2bps equates to one bit every five seconds — and the test message, “O CANADA,” encoded at five bits to the byte, is 40 bits. That’s over three minutes to transmit an eight-character text message. As the researchers note, though, transmission rate could be significantly improved by increasing the complexity of the system — multiple chemicals, better detection algorithms, multiple-input multiple-output (MIMO), and even a better fan would all increase throughput dramatically.

Transmission rate aside, though, what we have here is an excellent proof of concept for molecular communication. Molecular communication is exciting because they tend to work very well in situations where normal wireless networks fall short. Because you’re ultimately dealing in concentration gradients, all you really need for molecular communication is a medium where the transport phenomenon of diffusion is possible. Diffusion is where molecules naturally flow from areas of high concentration to areas of low concentration — and this readily occurs in air, water, and other fluids (blood, oil, etc.) Where a wireless signal might be blocked by a huge lump of concrete, metal bulkhead, or Faraday cage, molecular communication can be used pretty much anywhere.

Molecular communication - transmitter and receiver

The text message being encoded on the left, and the signal that’s received on the right (click to zoom in)

The most obvious use cases for molecular communication networks, then, are where normal wireless communications lose their efficacy. Reporting on a city’s sewer system, for example, would be a prime use for molecular comms. As would the ruin of a collapsed building or disaster site. We could also imitate nature and use molecular communication to link together medical implants– a sensor in your heart, for example, might use your blood as a transport medium to communicate with a computer implanted just under your skin. There is also the distinct possibility that we could use molecular communication to talk directly to the cells that are already in your body, to marshal them into doing our bidding… but that’s another kettle of fish for another day.

Now read: Harvard cracks DNA storage, crams 700 terabytes of data into a single gram

Research paper: DOI: 10.1371/journal.pone.0082935 – “Tabletop Molecular Communication: Text Messages through Chemical Signals” (Open access)

ExtremeTechNews & Updates For Hardcore Tech Fans | ExtremeTech

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>