IoT Device Functional Test Solution

A Leading Hearing Aid Manufacturer Reduced Test Time and Costs with IoT Device Functional Test Solution

As a leading global manufacturer of hearing aids and complementary accessories, it is the company’s mission to improve lives of those experiencing hearing loss. One of the ways this is done is by integrating new technologies and capabilities into their products. The manufacturer’s latest project was to have Bluetooth® Low Energy (BLE) connectivity integrated into the hearing aids. This common RF standard allows audiologists to configure and test the device, and users can remotely control the device volume. This is especially helpful given the small size of the actual earpiece. Users with limited finger dexterity appreciate the ability to control sound levels from their smart phones, and using a phone app calls less attention to the hearing aid than reaching up to one’s ear does.

In addition, a BLE solution allows the user to position the smartphone or other microphone close to the noise source, which is not always possible if the microphone must be worn by the hearing aid user. Finally, BLE hearing aids can nimbly switch between input channels, so the user who is listening to one audio stream on a tablet or computer can quickly switch to an incoming phone call or a local conversation.

Special Test Firmware Creates Risks

The manufacturer’s original test solution used a special firmware to test the hearing aid. Under computer control, the hearing aid would transmit to a known-good radio, and then wait for the acknowledgment from the radio. If this transmit-receive test cycle completed successfully, the hearing aid was deemed to have passed.

There were several problems with this manufacturing test solution:

• The manufacturer had to load the special test firmware onto the hearing aid, and then later replace it with the final shipping firmware. This added time and complexity to get the product to market; and the extra product handling posed risks to the manufacturing process 
• The hearing aid was not tested with the actual firmware that the end user would be using. This opened the possibility the end user might encounter different device behavior than the test engineer. 
• In the test mode, the hearing aid was controlled via a wired computer interface. These added antennas (the wires) onto a very small product changed its RF characteristics. Physically connecting and disconnecting the hearing aid also added time and product handling risks to the test process.

A New Way to Perform Functional Testing for Manufacturing

The manufacturer turned to Keysight for a solution. It was crucial the manufacturer mitigate the challenges and risks of their manufacturing test solution to maintain their product quality. Keysight proposed testing the hearing aids using a customized, onebox, non-signaling test solution that included Test Automation Platform (TAP) software as a proof of concept for R&D validation. This solution achieved customer acceptance within three months.

The manufacturer then requested a similar solution for manufacturing test, but with full signaling test capabilities. Keysight introduced the X8711A IoT device functional test solution, a cost-effective over-the air (OTA) signaling test solution that allowed the manufacturer to easily perform BLE signaling power measurements. The X8711A makes an OTA connection with the device under test (DUT) by making full use of the signals present in the normal operation mode of the radios.

Key transmitter and receiver parameters that would be affected by manufacturing defects can be determined through quantitative measurements of the RF signals, ensuring device quality and performance. Test engineers could easily adjust test parameters to suit their testing needs with the optional TAP-based measurement suites. Best of all, the solution enabled the manufacturer to test their hearing aids in actual operation mode and with the final shippable firmware, avoiding any device handling risks.

With Keysight’s signaling test solution, the manufacturer was able to reduce cost, reduce test time, and ensure the quality of hearing aids before shipping them out to their customers.

Here are the key results:

• Over 25% of test time reduction per device, with OTA testing while using final shippable firmware. 
• Reduced test cost by 50% per test system, when compared to the original test system. Additional savings can be realized when the test setup is repeated to support volume production. 
• Enabled accurate, quantitative measurements to verify transmitter and receiver performance through the TAP-based software, instead of comparing to a known good radio.

The manufacturer was very pleased with Keysight’s X8711A test solution and the savings they were able to achieve in terms of test time and costs. Now, they have a solution that simplifies the product testing process, supports volume production as well as maximizes the throughput of their new hearing aid with BLE connectivity.