|3||Blue Light-Tracking Glasses
|Erik Lundin [erikjL2], David Yan [davidzy2], Jane Zhao [janejz2]
Blue Light-Tracking Glasses
Problem: The increased use of electronic displays has led to concerns over the effects of visible light on the eyes. While it is now widely known that UV radiation and blue light is very damaging to the eyes, there is currently no device that tracks the amount of exposure.
Existing Alternatives: Blue light glasses are glasses made with polymers or other materials that block blue light. These glasses do not track exposure time and only block light.
Solution Overview: A pair of glasses can be equipped with sensors to detect UV radiation and blue light. If the user is exposed for longer than a determined threshold then indicators will go off depending on the type of light that exceeded exposure.
Sensor package: Consists of at least two photodiodes to detect blue and UV light. Dichroic filters that selectively pass blue light (400~500 nm) will be placed near the photodiodes corresponding to blue light. The circuit will be calibrated to best respond to light coming from a screen at a distance of about 3 feet.
Sensor amplifier: Amplifies signals from the sensors using transistors and determines if the sensor output reaches the threshold for eye damage and sleep interference. This subsystem also includes a logic circuit to indicate to the counter the exposure time is increasing in the case of blue light. For UV light the indicator LED will light up any time the threshold is exceeded.
Power subsystem: Consists of the system that converts power from lithium ion batteries for internal use and a switch. It interconnects with the indicator, sensor, and timing subsystems. Also includes the necessary safety precautions for charging and discharging the battery
Counter subsystem: Consists of a basic counter IC and 555 timer IC, which will only be enabled when the sensor threshold is reached. When the user specified time has elapsed a signal will be sent to the indicator subsystem.
Indicators: Consists of one red and one yellow LED for blue light and UV respectively. As a threshold is reached, the LED that corresponds to that threshold will light up to alert the user.
User interface: Consists of two knobs at the side of the glasses and an on/off button. One knob connects to a circuit with a variable resistor/capacitor that adjusts timer frequency for the exposure time threshold. The other allows for the adjustment of the light intensity threshold needed to trigger the timer or indicator.
Criterion for Success:
Successful detection of UV radiation and blue light.
Counter counts only when detecting blue light.
Indicators go off when time exposure threshold is surpassed.
User can change intensity and exposure time threshold.