How wireless communication protocols make or break designs

The design process includes many critical decisions for engineers, such as which wireless communications protocol to use. Not only does the choice point to a host of different design implications, it can also make or break the user experience of a product.

Often this choice lies between Bluetooth and Wi-Fi. Take the case of Music: Not Impossible, a surround body wearable system that allows both the Deaf and hearing communities to experience music through vibration. In this product, the translation and communication of the music to the harness, wrist and ankle bands is central to a user’s enjoyment of the product. However, when the engineers at Not Impossible Labs started building proof of concepts, they ran into a problem.

While Bluetooth is a great low power option, optimal for mobile devices and other small, battery-operated designs, its 30-foot range was too short for the device to be used in a large music festival. Wi-Fi solved some of those problems, offering high bandwidth and a much larger 300-foot range. It introduced another problem, though.

“When the Not Impossible team brought their proof of concept to us, the devices were prone to interference. They couldn’t scale due to Wi-Fi’s limitations,” said Erich van Stralen, engineer and Avnet’s project manager for Music: Not Impossible.

So what happens when neither major protocol works for your design?

The answer? Broadcast LoRa

Newer Internet of Things (IoT) deployments can span for miles and communicate to dozens or hundreds of machines, so Bluetooth and Wi-Fi won’t work there either. While customized connectivity solutions can work, they also take resources, time and money to complete—things most startups don’t have in house.

When Avnet and Not Impossible started collaborating to help bring Music: Not Impossible to fruition, they agreed to try something Not Impossible hadn’t experienced yet: LoRa, an emerging standard in many IoT projects. LoRa, short for long range, provides the range and power consumption benefits that IoT implementations depend on without some of the struggles Wi-Fi and Bluetooth present.

It’s a proven solution from the broadcast side, which offers longer ranges, low latency and low cross talk. It’s also perfect for a wearable that has to work anywhere from a small concert venue to a giant music festival, navigating the complex communication challenges of broadcast not only from device to device, but also around and through hundreds or thousands of bodies.

Latency envelopes and the future of Music: Not Impossible

LoRa was one of the many design choices that helped in the successful beta launch of more than 220 Music: Not Impossible products in September 2018. With that launch behind the team, the next hurdle is continuing to scale and refine the design while still providing a good experience.

“As Not Impossible scales this technology, we’ll need to focus maintaining optimal synchronization,” Erich said. “When you add another dimension to a user’s experience, if any part is out of sync, it’s just awful.”

Erich notes that while sound and light travel at different speeds, they arrive at your body within the same latency envelope—or a span of time where you perceive them to be fully synched up. When you add vibration, it all still has to stay in the same envelope.

How big is that span of time? About 30 milliseconds. Not much time to translate the vibration protocol, have the user receive it, and keep it in sync with light and sound. But that can all happen in large thanks to this less-than-decade-old protocol.

“It could have been built with something else, but LoRa enabled this in a way that other protocols can’t,” Eric said.

Learn more about Music: Not Impossible and how this transformative technology was built.

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