# Title Team Members TA Documents Sponsor
57 Water Aliasing
Atreyee Roy
Siddharth Sharma
Luke Wendt design_document0.pdf

Atreyee Roy - aroy10
Siddharth Sharma - srsharm2


During the pitching session, our TA Luke Wendt talked about the Water Aliasing Project that we immediately took an interest in. The basic idea behind this project is to create an illusion by playing around with the frequency of water and the frequency of a strobe light. Even though many people have performed this experiment already, we plan to add some additional features to our design so it is more interactive for the user and does more than simply levitate or move up or down.

Hardware Description:

We will need to create the circuit for the strobe light that we plan to have on the side panels of our system so it can illuminate multiple columns of water. We will design a panel of LEDs that will be on for short bursts of time to have very sharp droplets visible. Ideally we plan to design this strobe light circuit with comparators, transistors (>10 A), and regulators, along with other generic components that we may need as we figure out the circuit. These will be mainly needed to create the short bursts of light (really narrow input signals). We plan to generate and control the frequency of our strobe light with a signal generator, so it is easy to change or maintain the frequency we need for any particular mode (up, down, still).

For the water, we plan to create 4 columns, each pipe from a water pump to recycle the water used, to be run at independent frequencies with small speakers. We looked into Piezoelectric benders (coin type speakers) that are tiny and their frequencies and start and stop times can be controlled with extreme precision. They also happen to be cheaper than other options.

Software Description:

We plan to integrate user interfacing in this project. What we envisioned is a simple app that has three buttons arranged one below the other, in 4 columns- one for each column of water. Through this app, we can control the up and down, or still, motion of each column of water independently. Then, simultaneously each column can have a different movement, based on the user’s wish. We plan to transmit a bluetooth signal with our app, which will be received by our controller to alter the frequencies of the speakers as required. This will be achieved by our code for the controller design.

We expect that once we can figure out how to transmit even one of these commands to the controller, the rest will be a matter of scaling and we can have the user play with the controls on the app to make the water flow as desired.

Important concerns regarding safety:

Since this is a water based project, we plan to do it on a small scale so it is easy to work on and portable eventually. We may encase the entire system in a glass box, with the strobe lights on the sides. We think this will also give it an aesthetic value, while being contained and safe, minimising spillage.


Our team consists of an Electrical Engineer and a Computer Engineer, with background in microelectronic circuit design, control systems, artificial intelligence, machine learning, along with a strong coding background.

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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