PURPOSE: This study aimed to develop and evaluate the feasibility and preliminary efficiency of a methodology to measure the mindfulness state using a wearable device ("Cap") capable of monitoring students\' levels of full attention by means of real-time measured heart rate variability (HRV). METHODS: The device was developed to export the data to the user\'s smartphone via Bluetooth, which in turn stores the securely accessible data in the cloud. The autonomous wearable device consists of electronic boards of the Arduino platform that detect the period in milliseconds between two subsequent referential R peaks of the QRS complex wave through infrared oxygenation sensor. RESULTS: In a population of 13 subjects (8 female, 5 male, age 16.1 years +/-0.58 ), the Z-test ( p < 0.05 ) using rMSSD (root mean squared successive differences) and the Toronto Mindfulness (Curiosity) Scale within two 50 min windows, shows that increased HRV values converge to high values for the mindfulness state when the time difference between Rn and Rn+1 samples is greater than 88 ms. CONCLUSION: The device proved to be viable and potentially effective for measuring the state of mindfulness. Thus, further studies should be conducted to test it on a large scale as well as in real classroom situations.