The Mechatronics class at South Dakota School of Mines & Technology has students form groups for a maze solving robot and free projects. My group decided to make an automatically shifting bicycle for our free project. We set up the bicycle to monitor the current speed and change the current gear in order to get the maximum workout.

Finding the speed

The bicycle tracked speeds at two locations on the bike. The first was the wheel speed. This let us know that the bike was actually moving and making progress. The second location was at the crank. This let us know when the rider might be coasting or if they are doing a lot of leg work without making much movement progress.

One of the labs for my Microprocessor Based System Design class involved making an electric cane for the blind. The cane worked by first taking measurements from an HC-SR04 sonar sensor. The range of the nearest object could be found by measuring the time from an initial pulse to a returning pulse.

Feedback was then sent to the user depending on the distance of the object. The device had two methods for creating feedback: a small vibrating motor and a small speaker. The closer the object was then the faster the feedback provided.

A simple bang-bang controller on a PIC32 microcontroller.

One of the labs for my Microprocessor Based System Design class involved making a simple bang-bang controller. Our embedded system was set up to mimic the typical heater system found within a home.

The system was able to increase the heat by running current through a 1/4 watt resister. When the heater got above the desired range, the current to the resister would be shut off. The temperature was monitored using a thermistor connected to the resister with silly putty. The putty helped to hold heat in and keep the two components closer together. An LED was added to help monitor when the system was heating.

A breakout board created in my Microprocessor Based System Design class for a PIC32 microcontroller. The board was a semester long project in which each student designed a board layout. The class then voted on the layout they liked the most and the winning layout was sent to a board house to have one made for each student.

Overview

We first breadboarded the basic layout needed to run the PIC32 microcontroller in a previous lab. A design with more features than this was a requirement for us to send the board to the board house. A valid design had to be able to fit in to a 3” by 5” clear case. The project had four feature levels that each student could choose from to use.