All Case Studies

Digital Reflex Hammer

Measures the force of a reflex hammer tendon strike to provide practitioners with quantitative feedback.


For over 100 years, reflex hammers have been used for performing routine neurological examinations. These safe, prompt and low-cost medical instruments are used to strike tendons with a specified amount of force to examine the central and peripheral nervous system.

However, the force of each tendon strike and the resulting reflex is subjective to how hard the clinician swings the hammer. Even professional athletes have trouble duplicating the same swing twice in a row! This is a problem for establishing reflex trends over time or when multiple practitioners are examining one patient. RFX Corporation set out to disrupt the industry with real-time force measurement that eliminates measurement ambiguity.


We developed a low-cost electronic device that displays the force of each hit on a series of LEDs. The development of this novel measurement technique began several years ago. The tool needed to be inexpensive to manufacture, achieve the required measurement range and accuracy, and not impact the hammer's weighting or how it is used. Working closely with the RFX team, WTI performed months of testing to validate the concept on a custom-built test rig.

We brought the idea to fruition with the design of the user interface, PCB, injection-molded enclosure, firmware development, device calibration, and manufacturing. As part of the product launch, WTI helped RFX Corp. rapidly scale up by assembling the initial manufacturing run in-house.


Key Features

Low-cost design
Unique form factor does not change how the hammer is used
Novel measurement technique