optional feature: Log light sensor readings (and phone orientation) to record light intensity during awakening

[richrobe]

would like put this on the table again - we can discuss about details :)

[richrobe]

Reason(s):

• Law, R., Hucklebridge, F., Thorn, L., Evans, P., & Clow, A. (2013). State variation in the cortisol awakening response. Stress, 16(5), 483–492. https://doi.org/10.3109/10253890.2013.817552
• Figueiro, M. G., & Rea, M. S. (2012). Short-Wavelength Light Enhances Cortisol Awakening Response in Sleep-Restricted Adolescents. International Journal of Endocrinology, 2012, 1–7. https://doi.org/10.1155/2012/301935
• Thorn, L., Hucklebridge, F., Esgate, A., Evans, P., & Clow, A. (2004). The effect of dawn simulation on the cortisol response to awakening in healthy participants. Psychoneuroendocrinology, 29(7), 925–930. https://doi.org/10.1016/j.psyneuen.2003.08.005

and of course Stalder, T., Kirschbaum, C., Kudielka, B. M., Adam, E. K., Pruessner, J. C., Wüst, S., Dockray, S., Smyth, N., Evans, P., Hellhammer, D. H., Miller, R., Wetherell, M. A., Lupien, S. J., & Clow, A. (2016). Assessment of the cortisol awakening response: Expert consensus guidelines. Psychoneuroendocrinology, 63, 414–432. https://doi.org/10.1016/j.psyneuen.2015.10.010