In measuring impact absorption capability of foams samples, a falling/drop weight impact tester is a good instrument to be utilized. However, the impact machine need to be equipped with force and displacement/acceleration transducers in to order to capture the fast event and this is often quite a costly investment.
By relying on the understanding the basic of force and displacement sensing coupled with a simple data acquisition capability, an existing drop weight impact tester has been upgraded to achieve to above mentioned objective. Two simple speed trap were developed in-house (using LED and LDR sensing concept) and attached to the impact tester. These traps are used to capture the travel time of the impact head for a given distance which can be converted into its velocity. A reuse force sensor from a discarded instrument was utilized and together with a DIY data acquisition unit to record the impact force subjected to the samples.