Fire Fighting Robot- Part 4 Spritzer Idea

As we changed the design of our robot, we continuously tested our mechanism out on the spritzer by powering the NXT motor. To our disappointment, the mechanism never worked because it wasn't powerful enough to pull the handle of the spritzer. As a result, something always broke off at the weakest point of our design. So we decided to get assistance from the professors because we were at the point where we didn't know how to make our mechanism work.

Professor Turbak first told us to focus on the mechanism without having it being attached to the robot. We would worry about attaching it to our robot later. So we designed a "spritzing unit" where the mechanism was attached to the motor, the spritzer and the Lego pieces . Unfortunately I do not have picture of this, but it looked like some kind of "spritzing gun" and we succeeded in making it pretty sturdy. Professor Turbak showed us a trick that would make our design sturdier and it was to add vertical components to our "Lego towers" so that they would not break apart. To increase the power supplied for pulling the handle, Professor Turbak also showed us that we could play around with the gears. We attached other gears of varying sizes to our main gear on the axle to increase the torque. We saw that going from small gears to big gears increased the overall torque and that it decreased speed of rotation. We ended up using a 15:1 gear ratio and we could really see a difference in the pull that the mechanism provided. Unfortunately, even with this gear ration, the mechanism still could not pull that handle.

Again, pictures would have been very helpful to show our "spritzing unit" and our gears, but in the end we ended up not continuing with our spritzing idea. Even with all the changes and reinforcements that we made on our model, the mechanism was simply not powerful enough to pull the handle on the spritzer. Every time we tested it out, something broke off of our model and it became very frustrating. To decrease the amount of force needed to pull the handle, we could have extended the handle but doing so would increase the amount of space and the amount of Lego pieces that we would need, adding weight to the car and making it harder navigate. It would also make our whole design more complex and we were not completely certain that it would successful, so because of the limited amount of time we had to complete the challenge, we thought it would be better if we left our spritzer idea behind and used our delrin mechanism for something a lot simpler.