Why is a customized fixture needed when using the PPG module for testing?

When testing the PPG function of wearable devices, the major difficulty is how to test the PPG function when the arrangement of LEDs and PDs on DUT differs from it of the testing equipment.

A fixture helps overcome this difficulty by assisting the DUT in aligning to the PPG module for accurate test results.

 

What are the plans for WhaleTeq customized fixture service?

The LEDs and PDs on the DUT should be aligned to the PDs and LEDs on the PPG module to achieve the best test results.

Please refer to the table below for categorizing your DUT and suggested plans.

Side-by-sideArrangements of
the LEDs and PDs on DUT
Non-side-by-side (specific patterns)
  Examples

• Can directly align to the WhaleTeq PPG module (standard)
• Only requires a customized optical signal fixture for securing the DUT

DUT Descriptions  

Can't directly align to the WhaleTeq PPG module
• Requires customized PCBA and fixture for properly simulating signals

    

• Refer to Q3 below【Plan ①】(by DUT's manufacturer)
• Refer to Q4 below【Plan ②】(by WhaleTeq)

Solutions to designing
customized fixtures
(and PCBA)

• Refer to Q5 below【Plan ③】(by DUT's manufacturer)
• Refer to Q6 below【Plan ④】(by WhaleTeq)

 

Note:
1. The pictures shown are for illustration purposes only.
2. After the customer applies to customized fixtures, WhaleTeq will evaluate the design of DUT to confirm whether it can be undertaken.

Plan ①-By DUT’s manufacturer (Side-by-side arrangement of the LEDs and PDs on DUT)

Plan ②-By WhaleTeq (Side-by-side arrangement of the LEDs and PDs on DUT)

*Note: Whether to provide the components depends on actual needs.

Plan ③-By DUT’s manufacturer (Non-side-by-side arrangement of the LEDs and PDs on DUT)

*Note: It's recommended to use the same LED and PD components as the DUT to have the identical wavelength of the optical signals for more accurate testing.

Plan ④-By WhaleTeq (Non-side-by-side arrangement of the LEDs and PDs on DUT)

Note:

1. If the PCBA and fixture need to be calibrated regularly, please inform WhaleTeq in advance so that the design team can reserve positioning points.

2. Whether to provide the components depends on actual needs.