This is documentation for impact testing infrastructure, intended to measure peak acceleration and energy return of foam samples.
The specs for the test are a mass of 7.8 kg, traveling at 1 m/s, with an circular impact area of diameter of 4 cm.
impactor/ contains design files for a release mechanism for the mass. This is built around a solenoid and a push-button quick release pin (90985A311 from McMaster-Carr).
pcb/ contains design files and firmware for an embedded logging system using the ADXL372Z accelerometer and the Cortex M0 Adalogger board for Micro SD Card integration and battery management.
fw/ contains embedded code for detecting impact, sampling, and writing to the SD card.
analysis/ contains an ipython notebook for analyzing the acceleration profiles, extracting peak acceleration levels and energy dissipation.
video/ contains details of video analysis of the drop test. For now, this is implemented with a Sony RX-100 IV camera shooting at 960 fps and the free software Tracker to analyze acceleration profiles.
I've been using this measurement device to characterize the dynamics of folded foam samples I've been producing. Below are the acceleration profiles of two folded samples compared against conventional foams.