Technologies are generally described for systems, devices and methods relating to blood pressure monitors. Blood pressure monitors may include a processor and a structure effective to be in communication with the processor. The structure may be effective to apply pressure to an object. Blood pressure monitors may include at least one photoreceptor effective to be in communication with the processor. Photoreceptors may be located in the device so as to be effective to detect light returned from the object while the pressure is applied. Blood pressure monitors may be effective to determine color values of the returned light, determine changes in the color values of the returned light, and determine a blood pressure based on the changes in the color values.
