Press release
Wavelength measures the light that sets your body clock
8 July 2026
Impulse Arc has released Wavelength, an iPhone app that measures the light in a room with the camera and says whether it is helping or hurting your sleep.
Wavelength reports melanopic light, the part of the spectrum the body clock responds to. From your readings and your schedule it builds a plan: when to get bright light, when to avoid it, and when the evening light around you starts to keep you awake.
What it is for
Settling a sleep schedule that has drifted. Moving sleep to fit a run of night shifts. Adjusting to a new time zone: enter a destination and Wavelength says when to seek daylight and when to avoid it, before and after the flight.
A notification arrives as each light window opens.
Where the numbers come from
The recommendations follow Brown et al. (2022, PLOS Biology) and the light response curves of Hannay et al. (2019, Journal of Biological Rhythms). Camera readings are approximate, not lab-grade. The app supports sleep and circadian alignment and does not diagnose or treat any medical condition.
Availability
Wavelength is on the App Store for iPhone. The light meter is free. Coaching is $29.99 a year after a seven-day trial.
About Impulse Arc
Impulse Arc LLC is a California software studio run by Ben Kazez, a concert singer who earlier created FlightTrack and founded Mobiata, acquired by Expedia in 2010. Its products are Wavelength, Continuo.fm, Absurdly Optimized and Ambleway.