A Day In The Life Of A Student Engineer In Lockdown — Building Ping Pong Ball Catchers & Stabilising Attachments
Another day, another blog post! Welcome back guys!
As you can probably tell by the title, this blog post is going to take us through any of the little tweaks or changes I made to Eli’s physical set up in order to complete the tasks. You know the suss at this stage, Eli must navigate the obstacle course (without simply using all his pre-programmed code) and then he has to catch some ping pong balls.
The Catcher
Obviously first things first here, Eli simply has no way to catch these balls in his current form so of course something had to be done about that. According to our assignment’s brief, the opening of whatever was going to catch these balls could only be 133cm². That’s not really that big, but that’s not a concern for this assignment, the launcher will have to worry about being accurate enough for that. Nope, all that was needed for this part was to construct something with that size opening and attach it to Eli and what better place to put it than right on top of his head. Of course, there wasn’t really any other options for this as placing something on this size on say, his front tray, would block the sensors and leave us in quite a pickle. So, with the objectives straight forward, I found myself a tissue box measuring 10.9cm x 11.9 cm and simply sellotaped it right on top of my little robot. A job well done!
Think I’m bluffing about the size? Check out the pictures and see for yourself. I’ve made them extraaa big here to avoid any ambiguity and show that indeed these are the accurate dimensions. I measured from the sides of the walls to get the most exact opening size, because at this level, every millimetre counts! It might not be significantly smaller, but at 129.71cm², I’m hoping to pick up some bonus points for having a catching area less than the maximum area specified.
Now there was no specifications on how deep the catcher could be, so I didn’t see any point in trying to cut down my little box. Anyways, it also helps reduce the possibility of a ball landing in and hopping back out. I also added some tissues on the bottom too to help further prevent this disastrous scenario. Eli likes his new, pretty hat/catcher anyway, what do you think?
The Stabiliser
Next, as advised by our professor, I chose to add a stabilising component to my robot. I know that I said in my assembly post that the balancing code worked faultlessly, however I did also say that there was hundreds of lines of intense coding. If I did want to use this piece of software, I would have to understand and comment it thoroughly for my assignment submission. My brain started to hurt even thinking about it so instead I opted to attach a small stabilising wheel to the front tray instead. We had an array of old caster wheels lying around so I simply picked the smallest one I could find, drilled the appropriate holes into my from tray and secured one onto the other using nuts and screws which I used an angle grinder to cut to size. In the very picture of Eli in this post, you can actually where I’d made the marks indicating where I needed to drill.
The only problem with this was that even the smallest caster wheel I could find was too big and now my robot was tilted slightly backwards. Worried that this would interfere with my sensors, I set about rectifying this. In the end it wasn’t too big a job; I removed the two gold supports connected to the front tray and instead attached the tray directly to the lower blue board and secured it using nuts and screws. All of this is shown in the pictures below!
The Counter Weights
Staying straight up while stationary was now mastered, however staying upright while moving was another story. This was easily fixed by adding just a little weight to the front of the robot. It was almost as if the front holder was built for this purpose and to sit perfectly my AirPod’s case!
Overall, they were three pretty quick fixes to my stabilising and catching dilemmas. There were no marks going for how ingenuitive our solutions to these problems were, the robot just simply had to be able to perform the tasks! Therefore, I didn’t see any reasons in overcomplicating things and simply just used what I had at my disposal. Of course a lego wheel or such would’ve been cool, but my caster wheel does the job perfectly, giving me freedom in all directions, and my tissue box is actually kind of pretty.
So I suppose that’s really all there is to say here! I think I’ve managed to keep it pretty short and sweet for once. However, there is some whopper posts coming on my fabulous launcher and clever code soon, the processes for which took a hell of a lot more thought and work. I’ve worked really hard on them so I hope you’ll stick with me and see all my hard work finally come to fruition! B-bye for now :)
