https://www.collingillen.com/trebuchet daily 0.75 2021-03-02 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8c1/1613614137589/IMG_0392.jpg Trebuchet Don't have a chopping block? Just use your largest engineering book. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/6036838db0a5fb092b51442d/1614185404307/Trajectory.jpg Trebuchet Step 1: figure out how far a baseball will go when not in a vacuum. Sorry physics 101, not good enough. I first started with the standard trajectory equations, then included the effect of drag using numerical approximations. Click the picture to access a Google drive link with an Excel file of my work. It includes a macro that solves the numerical equations and graphs the results. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/602dc53071ff614b08720d05/1613698513639/56426988_10157292913499695_6154244246002991104_o.jpg Trebuchet Step 1: figure out how far a baseball will go when not in a vacuum. Sorry physics 101, not good enough. I first started with the standard trajectory equations, then included the effect of drag using numerical approximations. Click the picture to access a Google drive link with an Excel file of my work. It includes a macro that solves the numerical equations and graphs the results. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8bd/1613698771365/Launch+Arm.jpg Trebuchet Launch arm. The neighbors didn't seem overjoyed during this process.. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/602dc545adbde660d1870540/1613698700913/Trebuchet+Math+-+1st+page.png Trebuchet Solving the trebuchet motion was a lengthy process. I first found the equations of motion of the 3 degrees of freedom system using Lagrangian mechanics. I then found the solution equations to the system of 2nd order differential equations using linear algebra. Finally, I used 4th order Runge-Kutta to solve the solution equations. Click the picture to access a PDF of my full work. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8bb/1613698371685/Counter+Weight.jpg Trebuchet Counterweight https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/602dc54cc7cf52778a4ac448/1613699248025/Trebuchet+Motion.PNG Trebuchet I used an Excel macro to graph the motion of the trebuchet, as seen above, and output the velocity of the projectile. Click on the picture to access a Google drive link with an Excel file of my work. The Excel file includes a macro that solves the 4th order Runge-Kutta equations and creates a graph. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8c5/1613698368730/Launch+Finger.jpg Trebuchet Launch finger https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8bf/1613698375222/Frame.jpg Trebuchet Frame https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/602f189f30070e0b45646be8/1613700246608/BMD+-+Launch+Arm.png Trebuchet I used the peak accelerations during the launch motion that I found with the Excel macro in the last step to determine the maximum forces each member would undergo. I designed the structures to handle the largest normal and shear stresses by manipulating material selection and cross-sectional geometry. The picture links a PDF of my work. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602f14986fd92b190f14e8ba/602f14986fd92b190f14e8c3/1613698381506/Treb_Inside.JPG Trebuchet Assembled https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/602dc512b2512177587f3fd8/602f18a7c2dfaa54eb2d6610/1613854257572/BMD+-+Pivot+Beam.png Trebuchet I followed the same process for the pivot beam as I did for the launch arm as these two would sustain the largest bending moments and shear forces. For more thorough details, click the picture to find a PowerPoint of my full design. https://www.collingillen.com/monte-carlo daily 0.75 2021-08-08 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/6032ea4059eef05b520926b9/1613949758158/Monte+Carlo_cropped.jpg Monte Carlo Photo credit to World Casino Directory. Click the photo for the link. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/6032f403f5472a1e60367c40/1613952123260/Fantasy+Football.png Monte Carlo https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/6032f993c984ea01f5fd2c87/1614564135759/joe%2Bburrow_cropped.jpg Monte Carlo This is Joe Burrow shortly after winning the 2019 College Football National Championship. I imagine it feels similar to when your code finally works. Photo credit to Jeffrey Marx via the Cincinnati Enquirer. Click the photo for link. https://www.collingillen.com/rc-aircraft daily 0.75 2021-05-15 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/6031b300c0b3b22cdb9d599f/1613869835885/Team+Pic.jpg RC Aircraft https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60317583c95f6a31e4d5655f/603192ab3b981c77c82d7d3c/1613874784737/FBD+of+Wing.png RC Aircraft I was in charge of analyzing the forces on the wings provided from our Aero team and creating the internal structures to sustain these loads. After studying older planes and going through a couple of designs, I settled with a box spar for the main spar that cut off before the wing tip, a full length rear spar just before the ailerons, and stringers to support the wing tip. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031ae0973f18c30bf6b46f6/1613869115347/Working+in+the+Shop.jpg RC Aircraft Making an empennage https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60317583c95f6a31e4d5655f/6031a9ca7806406cda63b08c/1613875249192/Wing+Structure.png RC Aircraft This was my final main wing design which I created in Solidworks. The main spar is highlighted in yellow, the stringers in green, and the rear spar in purple. The leading edge is covered in a thin balsa wood sheet to maintain its all important shape. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031af46c0c23b2ccbb9c849/1613869130784/Chen%2Bin%2Bthe%2BShop.jpg RC Aircraft Making a horizontal stabilizer https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60317583c95f6a31e4d5655f/6031a9dab065b425a5cc676d/1613876141307/Bending+Stresses+of+Wing+Structure.png RC Aircraft I then used Excel to calculate the stresses in each member along the length of the wing. Initial designs had the stresses exceeding the Sitka yield stress, which began an iterative process of the aero team shortening the wingspan and lengthening the chord until the wing structures could withstand the stresses. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031ae51acf1a904d0ef509a/1613869138428/Wing+Structure+v1.jpg RC Aircraft Main Wing v1 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031ae27f35fa24e7d75b0ce/1613869145643/Wing+Structure.jpg RC Aircraft Main Wing v2 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031ae6edba7f915ea67073f/1613869160562/Laser+Cutter.jpg RC Aircraft Laser cutting the ribs https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031ae90520a7560ba7a8515/1613869167706/Vertical%2BStabilizers.jpg RC Aircraft Vertical stablilzers https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031aed69e66a02673ab1bd8/1613869174884/Deflection+Testing.jpg RC Aircraft Deflection testing https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031aee26230de761c93079d/1613869232249/Thrust%2BTesting.jpg RC Aircraft Thrust testing https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/6031a7c13b981c77c82f04ca/6031aee7e8886f045c16f2af/1613869193795/Hi+Im+Sham+Bosshur.jpg RC Aircraft He has no idea what he's doing https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60317583c95f6a31e4d5655f/6031cc207738592b37a2129a/1613876414557/Main+Wing+Assembly.png RC Aircraft We followed a similar process for the Horizontal and Vertical Stabilizers. Click on the picture for a link to the structural PowerPoint presentation. https://www.collingillen.com/lobber daily 0.75 2021-03-02 https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/60347f114b84f979add049d2/1614053150992/Sketch.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/603479af3ca70f41a534317d/1614051766687/IMG_0792.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/t/603477b7b4f1dd783112ecc9/1614051339413/Classic+Engineer.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d22fea4683a490a7ca5/603578de002ae245ab8e3c2f/1614269582735/Learning+Arduino.jpg V.A.L. Step 1: what's an Arduino? I did about a dozen projects from my "How to Arduino" book to learn about electrical components, Arduino syntax, wiring diagrams, etc. Click the picture for a link to the book. I didn't get paid for any advertisement; it's just a good book. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/6035821ec1ac677c96f1c8cc/1614119462837/Classic+Engineer2.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d22fea4683a490a7ca5/60357abcd78be678127c0576/1614118837893/Lobbing.png V.A.L. I needed to figure out how fast does a can need to go to lob however far I want. For these relatively slow speeds and distances, I assumed there was no air resistance which makes this a simple problem straight from high school physics. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/603582d6547b8815f1827787/1614119654653/IMG_0793.PNG V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d22fea4683a490a7ca5/60357cc32d66f7727ac1f621/1614118960558/3+Bar+Linkage.png V.A.L. I had initially thought of using a 3-bar linkage to lob the cans, kind of like a car piston. But after working with the design for awhile, I decided it was at best, difficult to manufacture and implement, and at worst, an awful idea. I settled on a pneumatic piston for the simplicity. It's either up or down, and it has plenty of power behind it. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/60358d1aaf994e0f4fdf61d4/1614122282434/IMG_0796.PNG V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d22fea4683a490a7ca5/60357ac0b452724695e00fc7/1614118481362/Piston+Angle.png V.A.L. I wanted some way to adjust the angle of my piston, so I figured a kickstand of sorts would do the trick. I could make notches for any given angle fairly easily, and then I'd have an adjustable lobber. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/603582182a285f0da2a772c3/1614119458810/Bird%27s+Nest.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d22fea4683a490a7ca5/603578f15697591551679254/1614118515704/20210102+Wiring+Diagram.jpg V.A.L. My final wiring diagram for all the different components the Arduino was to control. I'd like to say I got here on the first try. I sure would like to. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/603582c3a1aca60cf205bcb3/1614119635832/Leg+Angles.jpg V.A.L. https://static1.squarespace.com/static/6026bee5111da040bd1fe57e/60356d64a857d34bbccad51a/603583f662365d2e7fc62656/1614119941783/IMG_0794.PNG V.A.L. https://www.collingillen.com/about daily 1.0 2021-03-01