Project

# Title Team Members TA Documents Sponsor
3 Blue Light-Tracking Glasses
 David Yan
Erik Lundin
Jane Zhao
 Charles Ross design_document1.pdf
design_document2.pdf
design_document3.pdf
design_document4.pdf
final_paper1.pdf
proposal1.pdf
proposal2.pdf
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.

Solution Components:

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.

Electronic Automatic Transmission for Bicycle

Tianqi Liu, Ruijie Qi, Xingkai Zhou

Featured Project

Tianqi Liu(tliu51)

Ruijie Qi(rqi2)

Xingkai Zhou(xzhou40)

Sometimes bikers might not which gear is the optimal one to select. Bicycle changes gears by pulling or releasing a steel cable mechanically. We could potentially automate gear changing by hooking up a servo motor to the gear cable. We could calculate the optimal gear under current condition by using several sensors: two hall effect sensors, one sensing cadence from the paddle and the other one sensing the overall speed from the wheel, we could also use pressure sensors on the paddle to determine how hard the biker is paddling. With these sensors, it would be sufficient enough for use detect different terrains since the biker tend to go slower and pedal slower for uphill or go faster and pedal faster for downhill. With all these information from the sensors, we could definitely find out the optimal gear electronically. We plan to take care of the shifting of rear derailleur, if we have more time we may consider modifying the front as well.

Besides shifting automatically, we plan to add a manual mode to our project as well. With manual mode activated, the rider could override the automatic system and select the gear on its own.

We found out another group did electronic bicycle shifting in Spring 2016, but they didn't have a automatic function and didn't have the sensor set-up like ours. Commercially, both SRAM and SHIMANO have electronic shifting products, but these products integrate the servo motor inside the derailleurs, and they have a price tag over $1000. Only professionals or rich enthusiasts can have a hand on them. As our system could potentially serve as an add-on device to all bicycles with gears, it would be much cheaper.

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