The Vaccine Rollout — How I Made My Rube Goldberg Machine

After the last assignment, I looked at my classmates’ launchers and realised how overcomplicated and difficult I had made life for myself. However as we know, there is always a silver lining and in this case, it means that this assignment should be right up my street! I am already the queen of overcomplicating everything for myself and so this assignment suited me down to the ground. After all, a Rube Goldberg machine is a chain reaction-type contraption which aims to perform a simple task in an overcomplicated and indirect way. We’re a match made in heaven. Just ask anyone who has ever seen the thought process behind my coding.

So where to start? Well, unlike the last assignment we were given absolutely no rules or regulations meaning we had complete free reign over what our machine would do and how it would do it. It was a nice change to any of our other assignments and was a chance to let our imagination run wild. That being said, there was probably more careful thought and planning gone into it than the other 15 page report I wrote up last weekend; and that’s saying something.

Being able to start and finish absolutely anywhere was almost a little daunting however as soon as you start looking around you there are tonnes of items around the house that get you thinking and begin to inspire new ideas. That wooden spoon? A projectile launcher. The soft plastic caps off aerosols or bottles of tan? Ideal to put a hole through and attach some string to hold balls in a pulley system. The list goes on. And if everyday items still aren’t capturing your imagination there’s a whole host of YouTube videos out there to spark a few ideas.

In classic Aoife fashion I decided to begin at the end. I spent a while mulling over ideas of what I could get my Rube Goldberg machine to actually accomplish. Instead of being generic, I decided to get topical and create a long, windy, utterly needless kerfuffle of ups and downs to give my little robot Eli a ‘COVID vaccine’. Ironic.

I had a plethora of ideas on how to go about achieving this it was just a matter of building and stringing them all together based on my resources. Thankfully, my resources were actually quite plentiful. We had not long finished doing up the garage of the house when this project was announced and I had loads of leftover lats and a big massive board at my disposal. Given I also had easy access to a drill, saw and router it would’ve been rude not to make the most of them. Here’s a little look at some of the other bits I collected around the house to have handy during my construction.

So stay with me now as I talk you through a few of the more major, technical components in my construction! Once again if any of you are wondering, any of the maths or equations in my blog are done using LATEX!

First thing’s first…

The Projectile Launcher!

I know I’ve already made a launcher this semester but why not use that knowledge and incorporate it into this project too with the added bonus of absolutely no rules, regulations or requirements this time round.

In the beginning, I had planned for the platform to be level and perhaps a ball or something similar to fall off one platform and land on one end of a see-saw, sending the other end upwards to launch another ball and keep the contraption moving. I soon found however that it was extremely difficult to get the right force required. Also given that the funnel I intended to use could only fit a bouncy ball and not a ping pong ball, I was going to need some extra force. Instead, I opted to have the ball-less end positioned higher and a mass connected underneath. I intended that a string or rope would be holding that end and then it was cut the mass would fall rapidly, propelling the ball forward. I couldn’t think of a way to cut the string but by putting a tea light underneath I was sure I could cause it to snap. I found in practise that the way the string snapped wasn’t clean enough unfortunately so in the end I began my machine by simply just releasing the string manually.

Once again I went back to my projectile equations and tried to figure out how far it would be possible to launch this missile. I wasn’t too worried about height as there would be nothing the ball would be required to fire over as such.

This time it was only necessary to focus on my range; this ball needed to be able to fire over atleaaast the length of the seesaw.

It should be noted in these calculations that I am neglecting the weight on the seesaw, air resistance, friction and may be making a couple of reasonable assumptions.

The time of 0.1s was an estimate. My mass of 340g made the firing rapid though which makes the fraction of a second a reasonable assumption.

In my calculations I noticed that by lengthening my radius (or mass from the fulcrum) my speed increased and hence so did my distance. By halving my radius to 0.1 m the range decreased by almost 4 times, to 0.22m. By the time real world factors were accounted for, this would not have been enough. Therefore I lengthened the that side of the seesaw and I achieved an ideal range in my experiments.

Next up in the sequence of events we have…

The Pump

After seeing my classmates put their previous electrical modules to use in the last assignment, I decided to hop on the bandwagon this time. I got myself a small switch, a fuse, a bit of cable, a pump, and a battery. It was a normally open circuit so when the ball landed down the pipe it’d sit on the button and close the circuit, turning on the light and the pump which would then fill a cup on the left and as you’ll soon see, kickstart my pulley system. The pump was hidden behind the board where the rest of the messy screws and cable ties were poking out. It really was its own version of the saying, ‘Business in the front, MESS in the back’. But what goes on behind the scenes isn’t important and hence I installed the light to indicate and symbolise the working of the pump.

The Pulleys

Now these pulleys are pretty straightforward. They both weigh the same at the start and then one fills with water and becomes heavier and goes downwards. It isn’t hard to picture but I said I’d do the maths anyway just to remind us of the different mathematical forces and equations at play. Plus it wasn’t hard and didn’t take long so why not.

So this is how they three elements worked together! There’s the same amount of marbles in both cups at the start but they serve to give the right hand cup enough weight to tilt the edge!

As you can see the cup on the left filled and the right went up, pushing against a little rotating ledge, triggering my next set up…

The Collisions

A quick thought back to my Leaving Cert Applied Maths gave me the idea of collisions. If one ball strikes an identical stationary mass, the velocity of the first ball will be imparted to the second ball. Don’t believe me? Take a look at the proof I did out below.

A simple but effective way to incorporate another engineering element into my machine. Of course, this didn’t happen 100% due to factors like friction and loss of energy through heat etc that were mitigated in my calculations. Also the staggering of my set up likely had some effect, but hey, it works pretty well and you can definitely get the jist of what’s supposed to happen. Take a look for yourself.

‘Rolling’ on from this section was a fun little element, not too engineer-y but interesting to watch nonetheless.

The Stairs

Gerrupp them stairs, these little gems worked seamlessly every time. As the marble from the last section continued on its journey it tipped the bottom of my very long screws and gave the marble on top and little push. I also placed some nails at the end of each slope, just positioned so that it didn’t interfere with the screw swinging but stopped the marbles from rolling off everywhere at the end of their run.

As you can see the last one rolls into a cap which is connected to a string which goes around a pulley and is connected to a nail on the other end. This then pulls the screw out of the tubing and then the balls that were once on top of the screw can shoot downwards. All very simple but odd/hard to put into words. I think I’ll just let the video do the talking.

A little video for the second half of this madness

I wasn’t quick enough to get the final part but here it is…

The Grand Finale

Eli rolls in/balls go zoom, syringe gets hit vaccine gets given, Eli rolls back out a happy robot. Easy Peasy.

Putting It All Together…

Now I was a little distraught when I seen this video Mammy had kindly taken with the best intentions. It was only after the happy cheer of the successful, final run and the pump, battery and tools being promptly whisked back to the mechanics where they were needed did I watch the video. I know it’s a bit far out so you can’t see all the inner workings and I hadn’t set Eli up nicely so he was a bit late for his vaccine but I hope that from seeing the other videos you understand each component of my Rube Goldberg!

Enjoy!