REBEL concrete strength sensing system (IMAGE) Purdue University Caption From beneath a concrete pour, this black circular sensor transmits data about concrete strength levels through a cord plugged into an aboveground device called a data logger. Engineers receive real-time data from this device through an app. Credit Purdue University photo/Greta Bell Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.