Week 9

Week 9 Goals:

• Test our machine in a section wide run through of each group's Rube Goldberg machines
• Integrate our machine more efficiently with the previous and proceeding groups

Tasks Performed:

     After arriving to lab, the first objective was to assemble the machine.  The type of balloons we used was changed.  Previously, we used smaller balloons, but unfortunately we ran out, so larger balloons were used.  In attempt to match the smaller balloons, the larger balloons were blown up to half their true size, but it was quickly evident that due to their extra "squishiness", they would not pop.  So, we had to resort to blowing the larger balloons to their full size.  This became an issue for its placement on our ramp (the final event).  It was too large, so we taped the balloon to the weights attached to the ramp, rather than the ramp itself.  Paper was still used to help to ultrasonic sensor read the distance away from the balloon.

     Also, before coming to lab, we tried to fix the switch transition into the proceeding group's machine.  Before, the switch would now be triggered for multiple reasons (see previous blogs).  Now, the switch can be triggered much more easily because we stationed a k'nex piece to it more securely.  We also added weights to the ramp to add some force onto the switch as the robot drives up the ramp.  

     In the section wide testing, the entire Rube Goldberg was ran three times, with lesser amounts of intervenes each time.  The last run through had about eight intervenes.  This would be the last test of the entire Rube Goldberg. 

     Though our machine components ran smoothly, the transitions were somewhat faulty.  Out of the three tests, the transition into our machine worked two out of three times, but the transition out of our machine failed to work once during the test.  Thus, even with the extra effort put in to try and fix the transitions, we still failed to make the transitions 100% reliable.  Some reasons the transitions may have failed include:

• poor alignment between machines
• lack of testing with other groups to integrate the machines
• lack of a better solution to the issue

Images of the machine are below in previous blogs.

Week 8

Goals for Week 8:

• Testing the Rube Goldberg machine with it integrated into the class-wide machine and see where the machine fails during each run.
• Work on transition to group 5 (toggling power switch on power strip)

Tasks Performed:

This week was very similar to last week in terms of testing the machine. A period of time for the machine's setup was given at the beginning of the lab and slowly, group by group, the class-wide Rube Goldberg machine was formed with every machine connected to its adjacent groups. A picture of the our individual machine in the overall machine can be seen below.

Like last week, the machine was run through and each group took account of where their machine failed. For the first run, most everything worked in portion of the machine but the final transition event where we transfer the energy of the machine to group 5's machine. We made a note of this and during the setup for the second run of the machine, we carefully positioned the ramp so that it toggles the power strip so that it would click the switch and make the hand-off. On the second run, however, we ran into a number of issues. The robot did not knock the keychain on the wire enough to get it to move down, the balloon did not pop, and the transition yet again did not work as planned. 

The first two event failures could have been easily avoided as the balloon was admittingly positioned too close to the robot causing it to stop too soon. The reason the balloon did not pop is because it was not inflated enough for the push pins on the pendulum to puncture it. It was evident however that the transition to group 5's machine needed to be worked on outside of the lab. 

Group 5 graciously gave us the power strip used in their machine so we could work on the transition on our on time. On Friday, we all met and worked on this transition event. The problem was that there was not enough glue on the K'NEX piece attached to the switch, causing it to bend rather than toggle the switch towards the on position. To remedy this, we added more hot glue to help secure the K'NEX piece to the switch and prevent it from bending. After the glue cooled, we tested this event numerous times and got the ramp to consistently toggle the switch of the power strip. We are now confident that our whole machine will be ready for week 9's testing of the machine and that each event will be operational.

Week 7

Goals of Week 7:

• Test all machines working at the same time

Tasks Performed:

This week's lab consisted entirely of the setup of machines and a run through of all the machines.  Many problems that weren't considered were faced during this lab.  The most notable one was set up time.  The time it took to set up all the machines took around an hour.  Some problems were certain groups machines not fitting and/or going over their boundaries.  One group had to saw through their wood in order to receive a marble from the previous group.  Another flaw was choosing to set up the Rube Goldberg machine over an outlet, so a different outlet had to be used, and no extension cords were available.  A problem we faced was that the group before us, group 3, had their last event go too far into another group's territory.  They then had to readjust the ramp of their last event which in turn took the ball that would roll down off course and so during the test the ball did not hit correctly into our robot and it didn't work.  

Another problem we faced was connecting our last event to group 5's first event.  When testing this transition it was inconsistent, and the problem was our robot did not way enough to set off the other group's power strip.  To fix this problem we put small weights on the edge of our robot that will give it slightly more weight, just enough to cause our last event to work correctly.

Pictured is our Rube Goldberg machine in place along with the other machines during the setup.

Week 6

Goals of Week 6:

• Demonstrate reliability of Rube Goldberg
• Test with adjacent groups

Tasks Performed:

This week began to work on reliability within our own Rube Goldberg.  We encountered many minor problems this week that were not considered before.  A common problem was in our first event transfer, the robot would hit the ball of event 2, but it wouldn't slide down the rail.  This was due to carelessly placing down the robot.  Now the robot is placed in the correct spot every time which is marked on the board.

Another common problem was the robot's ultrasonic sensor not sensing the balloon in front of it.  This was difficult because the balloons varied in size and were very inconsistent.  A solution we found was taping a piece of printer paper to the balloon, almost like a wall to make a big target the robot could not miss.  There is no problem when the balloon pops because the paper falls out of the way.

When about to demonstrate our Rube Goldberg machine the phone fell and caused the last few events to trigger.  This was due to the phone receiving many text messages.  The solution to this is putting the iPhone on "Do Not Disturb" mode, and only allowing FaceTime from our computer allowing the phone to vibrate. 

Attached is a video of the complete Rube Goldberg running properly.

Connecting our first event to the previous group's Rube Goldberg proved to be a challenge.  Our first event begins when something hits our Robot's touch sensor.  The previous group has a ball that will roll down into the touch sensor, however it is not yet accurate enough to hit it in the correct spot.  After many tests we've concluded that making a K'NEX track to guide the ball would work, and possibly using a more dense ball would help with reliability as well.  We tried the transfer many times: a few times it worked, many times it ran off course, and sometimes the ball would hit the sensor without enough force to trigger anything.

Our last event involves our robot pushing down on a ramp hard enough to activate a power switch on the other team's side.  We were unable to test this this week because the other team added a K'NEX piece with hot glue to the power switch which did not dry in time.  Our ramp has been modified slightly to have more weight so it takes less force to push down the button.  The idea is to have the weight from the robot going from one side of the ramp to the end be enough to trigger the event change.

Week 5

Goals of Week 5:

• Create the final event (event #6)
• Integrate each event on the 2' X 3' sheet of plywood

Additional Materials Brought to Class:

• Everything from previous weeks
• Balloons
• Weights

Tasks Performed:
      Event 6:
      At the start of class, event six was created.  Event six consists of a ramp (see image below) which is triggered by the swing popping a balloon, which then pushes down on the next groups power surge, starting their machine.
     To build the ramp, a stack of yellow pencils was duct taped to the bottom of the one square foot sheet of plywood.  This allows the ramp to pivot over a center point.  After some testing, a barrier at the opposite end of the ramp was added to stop the robot from advancing into the next groups events.  Further, to add force onto the switch, external weights were added to the ramp to help push the power surge's switch down.  (see image below)
     The ramp has an attached balloon that will stop the robot (event one) from advancing forward due to its presence in front of the ultrasonic sensor.  After the balloon is popped by event five, the robot can advance up the ramp.  Once the weight of the robot moves past the center point, the ramp will have enough force to push down the power surge's switch.

The ramp (seen bottom left) is the final event

The main alteration to this event are the weights--without them, the ramp does not have enough force to press the switch.  Also, something to keep in mind is the type/size of balloon.  If the balloon is too small, it won't stop the robot from advancing forward and will not pop as easily; however, if the balloon is too big, it won't fit on the ramp.
 
     Event Integration:
After all the events were completed, each event was placed on the plywood for machine integration (see previous weeks for plywood stencil).  A video on the complete transition between events of the Rube Goldberg will be provided in the coming weeks.  Some notes on how to better the machine are as follows:

• create more structural support for events (increases accuracy of events)
• add a weight to the bottom of the pendulum (adds force to the swinging motion)
• use specific size/shape balloons (increases pop rate)
• add weight to ramp (adds force into the switch)

Top view of Rube Goldberg Machine

Side View of Rube Goldberg Machine

Improvements for next week:

• Add the ball back onto the board holding the iPhone up
• Create more reliability in transitions