Set up of the reaction Time test Download Scientific Diagram Arduino Spede A Speed Reaction Time Tester Showcase Arduino Forum Figure 2 from Portable Reaction Time Measurement Device: Prototype Set up of the reaction Time test Download Scientific Diagram Arduino Based Reaction Timer Improve Your Reaction Time The DIY Life. The Reaction Tester is based around the 555 timer IC. The kit is designed to test and expand one's sense of timing. The students need to synchronize their reaction time to press the button in time to keep the LED lit or else it goes out. Note: Step by step instructions are not included use the included parts list to identify the components and assemble according to the included circuit diagram. Jumper wire not included (breadboard accepts 21 to 26 AWG wire).