The Zeo™ wireless headband collects sleep data through the proprietary soft sensors that rest on the forehead. Zeo approached Altan to find a working solution to a previously unsolvable problem. They needed a way to create an extremely reliable RF communications link between the headband and the base station.

Altan began by reviewing the existing circuit design, component selection, printed circuit board layouts and mechanical construction of both headband and base station.

Testing indicated poor reception of the base station transceiver and inferior output of the headband transmitter.

Headband operation was tuned and optimized, yielding immediate improvements that Zeo could measure.

Next, Altan staff measured and documented the existing system performance, then defined the necessary changes to component selection and printed circuit board layout that would provide significant improvements.

To help Zeo understand the expected performance of the system, Altan developed a link budget for the application to show that Zeo’s performance targets could be met.

Altan simulated key portions of the updated solution to validate proposed changes.

Then, Altan staff guided the Zeo team through the required changes, including:

• component selection
• modifications associated with correct shielding
• grounding and antenna circuit methods
• providing detailed instructions for each change

Once the changes were implemented, Altan tested and tuned the updated headband and base station units, then conducted field tests to validate the changes. The improvements were dramatic.

Achieving success required 2.45 GHz ISM band expertise including RF circuit simulation, impedance matching, PCB transmission line design, use of PCB and chip antennas, and knowledge of Texas Instruments Chipcon CC2500 and CC2550 devices.

In addition, Altan engineers assisted in the refinement of Zeo’s proprietary FHSS protocol, used for communications between the headband and base station, to greatly improve its reliability.

Working with the Zeo team, Altan's engineers were able toidentify and solve critical prototype development problemsthenintegrate the solutionsto providefully functioning Zeo™ headband and base station modules.

Overall, the wireless connection was improved with an increase in the link budget by > 10 dB, and a reduction in packet error rate by a factor of 20, at the required operating range. As a result, the link range was increased to meet the established product requirements:

In addition, by improving the FHSS protocol, costly hardware changes were avoided.

Altan Technologies and their team of engineers were able to rise to a specific challenge for Zeo’s new sleep monitoring invention – one that was critical to its success. Without Altan’s specialized knowledge of RF devices and the robust software required to support them, Zeo’s new product might have remained more of a dream than a commercial reality.

• Company: Zeo Inc. (formerly Axon Labs), http://www.myzeo.com
• Product: Zeo™ Personal Sleep Coach
• Contact: Ben Rubin – CTO and Vice President of Development