Step One: Movement

In order to find the candle, we need to build a robot with the ability to turn. We included a differential gear, along with two motors attached by pulleys. We believe that this will allow the robot to direct itself toward the candle. However at this point, more torque is needed to turn, due to the amount of weight it is carrying.

We determined that the differential gear that we made was wrong and unnecessary. What we really need are two completely independent motors and gear trains.

Movement, cont'd

We rebuilt the wheel structure, with two separate gear trains, each run by a motor. Each gear train provided a 27:1 reduction.

This change was successful, in that the wheels do now run and allow the vehicle to turn. However, since the front wheels are not powered, they do add a significant amount of friction, so the vehicle cannot turn very effectively.

Step Two: Sensors

In order to identify the candle, we place two infrared sensors at approximately the candle's height. These will display a siginificantly lower reading when near the candle. Another infrared sensor will be used to detect differences in color. A white circle will surround the candle. As the front of the robot detects the sudden difference in reflected light, it will stop and be ready to extinguish the candle.

Due to our concerns with the precision of the spray of shaving cream, we decided not to implement these sensors. However,in the competitive model which we will be working on, we plan to use a sensor design very similar to this.