https://forum.arduino.cc/t/pvc-pipe-impact-sensing/18803
PVC Pipe Impact Sensing - Interfacing - Arduino Forum
Jun 28, 2010 - Hi, I need help finding the best way to tell if someone has hit the end of a PVC pipe. I'm working on a project for my scout troop that will be used in our...
pvc pipeimpact sensinginterfacingarduinoforum
https://data.epo.org/publication-server/rest/v1.2/publication-dates/19980617/patents/EP0708925NWB1/document.html
IMPACT SENSING SYSTEM - Patent 0708925
IMPACT SENSING SYSTEM - Patent 0708925
impact sensingsystempatent