feature article
Subscribe Now

Chirp Does Data Over Sound

Quirky Network Technology can be Retrofitted to Almost Anything

“Lovers of audio books learn to live with compromise.” – David Sedaris

“Oops! I forgot to add the Wi-Fi!”

How many times has this happened to you? You design and deliver a great product, ship millions of units into the market, and then realize too late that you forgot to add the wireless networking? Boy, is your face red.

Cheer up, friend. There’s a solution to your problem. And it doesn’t involve product recalls, PCB rework, new components, or awkward conversations with the purchasing department. In fact, it’s just a software fix. Whew! I bet the boss will never know. Thanks, Chirp!

Thanks, who? Why, Chirp, of course, the cheerily named 10-person startup located in central London that has transmogrified an old technology into a new solution. Chirp does wireless networking without the wires – or any RF components at all. How’s that work? The hint is in the name.

Chirp does data-over-audio. They modulate sound, not radio spectrum. When Chirp says they transmit over the airwaves they really mean air waves. Practically any device with a speaker can transmit, and any device with a microphone can receive. That means lots of old MP3 players, tablets, digital picture frames, speakers, e-readers, or cheap flip phones can potentially use Chirp’s technology to add local-area networking purely through software. No RF components and no hardware add-ons. Fun!

Chirp’s range is roughly the same as that of Wi-Fi. Basically, if the device is within earshot, it’s close enough to exchange data. A loud device (a public address system, for example) could reach across an entire stadium, while a quiet device might reach only a few meters. Or a few inches. You could also simply turn the volume up or down to adjust the broadcasting range, a nicely intuitive method that RF devices don’t really offer. Worried about someone eavesdropping on your data? Close the door and turn the volume down.

What Chirp isn’t is fast. It’s orders of magnitude slower than either Bluetooth or Wi-Fi, so think carefully about how much data you need to transmit. Plan on data rates in the range from about 20 bits/second up to 1K or 2K bits/second, depending on ambient noise and other factors. Think of Chirp as a kind of QR code: a simple way to represent limited data using a different medium.

On the plus side, Chirp doesn’t require the tedious pairing of Bluetooth or the SSID/passphrase exchange of Wi-Fi. “It’s 2019 and we still haven’t sorted out Bluetooth pairing or how to connect to the meeting room projector,” says Chirp CEO James Nesfield.

To leverage the billions of existing audio input and output devices already in the field, Chirp restricts itself to the audio spectrum, meaning roughly 20 Hz to 20 kHz. Virtually any device can transmit and receive at those frequencies (and often well outside of that band as well), so it’s a safe bet that any past, present, or future gizmo that makes noise can do so at the appropriate frequencies.

That doesn’t mean that Chirp’s chirps are necessarily audible to humans. That’s a user option. Although the “audio” spectrum is usually defined as 20 kHz and below, most humans can’t actually hear anything above 17 kHz or so. That leaves a small band of perhaps 2 kHz at the top end of the spectrum that is imperceptible to humans but is happily supported by cheap commodity speakers, transducers, and microphones. If you want your data chirps to be inaudible, simply configure the software to use the upper end of the audio spectrum.

On the other hand, Chirp works just as well as an audible data transfer, in which case “it sounds a lot like R2-D2. It’s a digital birdsong kind of sound,” says Nesfield. Chirp can also layer on top of existing audio, such as music from an MP3 player or PA announcements. That means you can mix audible and inaudible data. Chirp doesn’t replace a device’s native audio; it complements it.

The uses cases for Chirp are… not always immediately obvious, even to its creators. At one extreme, a supplier of nuclear power plants uses the company’s technology as a low-bandwidth IoT network to monitor the health of its industrial equipment. The plant is hugely noisy (above 100 dB, too loud for human occupancy), but Chirp-enabled devices have no problem communicating above the din. At the other extreme, kids’ handheld games use Chirp to network up to eight nearby players, like a LAN party without the network cables.

In a business setting, Chirp sees its technology as an alternative to Bluetooth beacons, which can unintentionally penetrate walls and floors, whereas Chirp can easily be restricted to a single room. One customer in India uses Chirp as an electronic ticket taker. Passengers simply wave their phones in the general direction of the ticket machine and it validates the fare. The system works better than QR codes because it doesn’t require line of sight. Or even light; sound travels just fine in the dark.

Chirp’s business model mirrors that of most software companies. There’s a recurring license fee for access to the technology, which allows the developer to deploy as many devices as they like. There’s no per-unit or per-byte royalty.

“We’ve basically reinvented the modem,” says Nesfield, with some justification. Transferring data over sound is an old process that includes SOSUS, SONAR, medical ultrasound imaging, 300-baud Hayes Stack modems, and scores of other applications. Wi-Fi, Bluetooth, Zigbee, and other RF networks may be faster, but they’re also way more complicated and can’t be retrofitted to existing devices like Chirp can. Plus, you don’t get to hear the data. As a software-only network addon, Chirp turns old tech into something useful and new. Simple networking. Just add software.

Leave a Reply

featured blogs
Dec 7, 2021
We explain the fundamentals of photonics, challenges in photonics research & design, and photonics applications including communications & photonic computing. The post Harnessing the Power of Light: Photonics in IC Design appeared first on From Silicon To Software....
Dec 7, 2021
Optimization is all about meeting requirements. In the last post , you read about how you can use measurements to optimize a circuit. This post will discuss the use of curve fitting to optimize a... [[ Click on the title to access the full blog on the Cadence Community site....
Dec 6, 2021
The scary thing is that this reminds me of the scurrilous ways in which I've been treated by members of the programming and IT communities over the years....
Nov 8, 2021
Intel® FPGA Technology Day (IFTD) is a free four-day event that will be hosted virtually across the globe in North America, China, Japan, EMEA, and Asia Pacific from December 6-9, 2021. The theme of IFTD 2021 is 'Accelerating a Smart and Connected World.' This virtual event ...

featured video

Imagination Uses Cadence Digital Full Flow for GPU Development

Sponsored by Cadence Design Systems

Learn how Imagination Technologies uses the latest Cadence digital design and simulation solutions to deliver leading-edge GPU technology for automotive, mobile, and data center products.

Click here to learn more about Cadence’s digital design and signoff solutions

featured paper

Add Authentication Security to Automotive Endpoints Using the 1-Wire Interface

Sponsored by Analog Devices

By adding a single authentication IC, automotive designers can authenticate a component with only one signal between an ECU and endpoint component. This is particularly important as counterfeit and theft are increasingly problems in automotive applications. This application note describes how to implement the DS28E40 Deep Cover 1-Wire Authenticator in a system to provide authentication for optical cameras, headlamps, EV Batteries, occupancy sensors, and even steering wheels, and more.

Click to read more

featured chalk talk

Build, Deploy and Manage Your FPGA-based IoT Edge Applications

Sponsored by Mouser Electronics and Intel

Designing cloud-connected applications with FPGAs can be a daunting engineering challenge. But, new platforms promise to simplify the process and make cloud-connected IoT design easier than ever. In this episode of Chalk Talk, Amelia Dalton chats with Tak Ikushima of Intel about how a collaboration between Microsoft and Intel is pushing innovation forward with a new FPGA Cloud Connectivity Kit.

Click here for more information about Terasic Technologies FPGA Cloud Connectivity Kit