Design & Development of Pendulum Impactor

impact pendulum 1

Pendulum Impactor

Ratchet and pawl mechanism.


The main objective of this project is to design and build a pendulum that determines the reliability of small components under high G-force. This is used for the small receiver that is used in a hearing aid. 

It is an important test as part of the qualification process to ensure that the receiver in the hearing aid is able to withstand a certain threshold (G-force)so that it continues to function in the event the aid falls to the ground.


The pendulum is designed so that it reaches a maximum G-force of 20,000 G and allows for a one-man operation. To achieve this, a ratchet and pawl mechanism as shown in the figure is incorporated into the shaft that allows the arm to be locked at different angles. An angle indicator shown in the figure is built into the shaft to measure the angle of the arm.

A lock is integrated into the lever, shown in the figure, which prevents the arm from being released accidentally to ensure safety of the user and injury from unexpected impact. Another feature of the pendulum is that the pendulum ball and impact plate which are directly involved in the impact can be replaced easily as they will be subjected to many high G-force collisions and will be worn down over time.

The whole pendulum weighs approximately 150 kg and is about 0.5 m wide, 1.2 m tall and 1.5 m long inclusive of the arc of the pendulum arm. The whole structure is designed to be modular so that it can be dismantled with simple tools and parts can be swapped out easily. Some of the components were bought from MISUMI, for example the ratchet and pawl, so it can be purchased as standard parts instead of having to fabricate them.

Project video

Project Video Clip

School: School of Mechanical & Aeronautical Engineering

Course: Diploma in Mechanical Engineering

Supervisor: Lee Kim Kheng

Students: Chng Zong Han Joven, Low Qi Wen Keith, Boh Chang Wei Darren

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