Our task this past week was to build a safer bajaj. Through rapid prototyping we had to create a vehicle that would slide down a zipline the fastest without losing its passengers (two ping pong balls). Just like a real bajaj, when tipped upside down the passengers had to fall out.

In order to do this, we created a main chamber to hold the ping pong balls out of plastic cups and suspended a heavy weight underneath it. This weight (consisting of bouncy balls) was what maximized our speed down the zipline. We kept the balls inside the cup by using two sticks across the back side of the cup to block them. We also added padding to the front of the cup to absorb the impact. To attach the bajaj to the zipline we used a paperclip. Our bajaj performed very well. We had two successful test runs that were quite speedy.

In the second iteration, our team tightened up the design, such that the weight was not freely suspended, but pattached rigidly to the cup. We added weight by filling the weighted cup with sand. We also used a binder clip instead of a paperclip. While our first run failed as both the ping pong balls fell out, our second run was a success. On average the two runs were a second faster!

While I had done the bajaj challenge several times before, I still found it to be a fun exercise in rapid prototyping.