Special Circuit :: ECE 445 - Senior Design Laboratory

Special Circuit

A student whose Senior Thesis Project (ECE 499) does not involve the design and construction or testing of electronic devices or hardware is required to complete a Special Circuit Project in the ECE 445 lab during the semester they take ECE 499. In addition, students enrolled in ECE 445 who are not undertaking a hardware dominant project are required to complete the special circuit (although this is strongly discouraged and the course staff will work with your team to make sure you have enough hardware in your project to avoid having to complete the special circuit.)

The special circuit is typically posted in the middle of the semester. Once you sign up for the special circuit (see below), you will be assigned a TA, a locker, and a special circuit which generally takes about 12-15 hours to complete. When you have it designed and built, you will give a functional demonstration to your TA, who will then inform the professor who will inform undergraduate advising that your task is complete. You are NOT required to attend any of the classes, reviews, demos, or presentations associate with the ECE 445 class.

Sign up for Spring 2020 is now open

Sign up for the Special Circuit assignment on the Lab Access page. Instructions for completing the special circuit will then be provided in the near future. Please check this page for updates.

Link to all Special Circuit design problems. 

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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