## 2 Materials and Methods  
For our experiment proposal, we decided to analyse 3 independent variables: sleep time, light exposure and sleep position.  
* Sleep Time-Sleep time is essential to get a good quality sleep because our body needs to complete sleep cycles which consist in 90 min each one.
* Light exposure-To sleep well during the night, we must sleep with a blackout, which means no light should disturb our time of sleep.
* Sleep position-Sleep position is a vital element to have a good quality sleep because it affects directly how we breath and move, so that we should try to adopt a fatal position to improve our sleep.  
We began by collecting sleep quality data from sleep habits and quality from a group of 30 people from Guadalajara to tell whether there's a relationship between sleep quality and adopting 3 good sleep habits (sleeping complete sleep cycles, avoiding light exposure and adopting a fetal position). The following process of 5 phases is our proposal to get our results.  
Through the study, we mention the use of non-invasive devices, which we define as devices that are not in direct contact with the person involved. In the medical sector we may use invasive or non-invasive devices that interact directly or indirectly, respectively, with the patient. Since our work uses different system types to determine how our results are obtained. Furthermore, invasive devices should be used by the patient most of the time  
\begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Reference** & **Metrics** & **System Type** & **\% Sleep Improvement** & **Experimental Validation Period** \\ \hline
[29] & Minutes asleep, Minutes awake, Number of awakenings, Minutes to fall asleep, Sleep efficiency & Invasive & 5\% & 2 weeks \\ \hline
[30] & Bed time, sleep onset latency, the number of times they woke up during the night, wake after sleep onset, final wake time, the time they got up, and how long they spent in bed & Non-invasive & No reported & 1 week \\ \hline
[31] & Sound amplitude, Acceleration, Light intensity and screen proximity, List of running apps, Battery states, Screen states, Sleep diary & Non-invasive & 16\% & 1 week \\ \hline
[32] & Factors relating to their sleep quality and environmental conditions to look for trends and potential causes of sleep disruptions & Non-invasive & No reported & 2 weeks \\ \hline
[33] & Power spectrals of moving, snoring and coughing & Non-invasive & No reported & 1 week \\ \hline
[34] & Best effort sleep (BES) model: sleep duration & Non-invasive & No reported & 1 week \\ \hline
[35] & Vision-based sleep monitoring system, Breathing & Non-invasive & No reported & No reported \\ \hline
[36] & sleep status, on-bed movement, bed exit, and breathing & Non-invasive & No reported & 1 week \\ \hline
[37] & Average total sleep time (TST), \% wake, \% rapid eye movement, and \% non-rapid eye movement sleep & Non-invasive & No reported & 2 weeks \\ \hline
[38] & Total sleep time, sleep onset latency, wake after sleep onset, and sleep efficiency & Non-invasive & No reported & 1 week \\ \hline
[39] & Sleep, such as body movement, cough and snore & Non-invasive & No reported & 26 weeks \\ \hline
[40] & Breathing rate, heart rate & Non-invasive & No reported & 2 weeks \\ \hline This work & Heart rate, Breathing frequency, Temperature, Oxygen saturation, Total sleep time, REM sleep, Deep sleep, Heart Rate Variability, Snoring & 15\% & 4 weeks \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison of metrics with related work to sensors and/or wearables for sleep monitoring.  
to obtain these data. In our study, we use mostly non-invasive devices as these are placed around their bedrooms [41].