Robotics by TK

Improvement in quality I decided to try 3D printing with PETG since PLA has limitations when it comes to heat resistance and strength. People in 3D printing forums suggested PETG and ABS, but they warned me that PETG is difficult to print. I had scoured the internet trying to find out what perfect 3D printing profiles would result in good quality prints. Almost all of them emphasised that a hot-bed was needed. Now I have two 3D printers, one with a hot bed and one without. My 3D printer with a hot bed has a Bowden Tube, and some people warned that PETG does get stuck in Bowden Tubes sometimes, which scared me a little bit. So, for my first PETG filament test print, I used a 3D printer with a direct drive extruder but no hot bed. I was initially scared that it wouldn't stick. But my first test print went well. The print was a 3 mm cube, and the resulting brim stuck well. Next, I decided to print a more complex image to see how it would fare. I had set the recommended PETG profiles;...

  So the other day, I lost two essential parts from a STEM toy kit. Not to worry I can always print a replacement , I thought.  I opened up OnShape and got to modelling. Using Vernier callipers, I measured their sizes and made exact dimensions on my CAD model.  Now, 3D Printers aren't usually very precise. You should account for a 0.03-0.05 mm tolerance when making a CAD Model. Because when I would print the part, and measure it with Vernier Calipers the holes would be smaller by about 0.03 mm. This meant that the part wouldn't fit in the holes. You can offset this by using the Hole Expansion setting in Cura, which works perfectly fine. But when it comes to the parts that need to be fitted, changing the settings in your CAD model is the way to go. I printed many versions of the hexagon shaft part, until I made one that fit perfectly with the other stem toy parts. Looks pretty nice, doesn't it?

  I tried my hand at making a Quadruped Robot; an 8-DOF one as opposed to the typical 12-DOF ones. It is still very much a WIP, but I just couldn’t wait to make a post about it. In the top most photo you can see how it is taking serial inputs from a GUI application. The application itself was made using Processing. The GIF below shows how I send the servo values using the interactive knobs and pressing the respective servo buttons. For instance, HLF would mean Hip Left Front and KLB would be Knee Left Back. So if I set the HLF knob to be of a certain value, and then press the HLF button, it will send a command to move the front left servo connected to the hip, to the desired position. The GUI establishes Serial communication with the Arduino.  Spent so many hours 3D Printing the body. (The STL files were obtained from this Instructables page ). To provide sufficient current to all my servos, I al...

  Guess what these are ? And what they're made from. (Hint: Check the post's tags!) I can't share the details yet, but if you are curious you'll have to come down to our company in Multan to figure it out! 

Those of you who have used MeshMixer for mesh repairing purposes must be aware how this software can be used for digital sculpting as well. Well let's just say I went a little crazy with it. The pointy finger hand was obtained from f ree3d.com. Thoughts? You may think it's weird. I call it avant-garde.  Cowboy hat obtained from source      No... I will not be entertaining criticism. 😏 Alright, I did cave in and try to make something more public-friendly. Daddy bear has a lovely pout! To conclude, I had fun working with MeshMixer. I'm definitely going to keep making organic models using the digital sculpting tool, and keep 3D Printing them. :)

Did you know that you can control your DSLR camera via command line instructions. Not me! And I wouldn’t have until I attempted this project. But that’s besides the point, this project goes beyond me simply using a DSLR camera to obtain a video feed. I used a 2-DOF pan-tilt rig powered by Arduino and the OpenCV library to track the movement of a person’s face. In a way, one could call this a rudimentary example of an animatronic head. If you move upwards, the head will tilt upwards to look at you. Almost like its gaze will follow in whichever direction you move. (Provided you remain within the frame, of course!) I tried placing several cute toys on the pan-tilt rig such as a duck or a sheep, and a ladybird. Setting up a DSLR camera for your video feed: I used a DSLR camera so that I can position the camera wherever I wanted to. In addition, you get a higher frame rate, better image quality etc… This project works with a laptop camera as well, which is what I was using at the be...

Note: This GIF has been sped up x 2 I took one look at Theo Jansen’s Strandbeest moving machines and thought to myself, “Wow I’d like to recreate that”. And recreate I did, but on a smaller scale. I also inadvertently made them less creepy as well. Here’s a video showing the originals models in movement. Pretty cool, right? Theo Jansen has also designed several more cool machines, do check them out on the official Strandbeest website [3].   According to the Strandbeest website and this paper [ 6 ], the model adheres to a group of Holy Numbers. The model and its respective Holy Numbers are shown above. The linkage is made up of two 3 bar linkages (our triangles) and 2 four bar linkages. [2] Image obtained from [2] The overall trajectory of the end-point forms a specific shape, known as the locus. Apparently, the locus’ phases have dedicated names, shown above. The set of Holy Numbers affect the shape of the locus. On e can optimize the locus’ shape to fit their requirements...

I came across several videos and posts about tensegrity structures and I became intrigued. I found this .stl file uploaded by an individual with the username Cowski on Thingiverse ( https://www.thingiverse.com/thing:4294837 ). Then, I checked if things were smooth on Cura and discovered that it was using quite a bit of filament, so I reduced the scale of the print to make it smaller. Also, I reduced the infill percentage as well, which ended up reducing the amount of filament required. This is the final print I got. During printing, there seemed to be a problem with adhesion which affected the quality of holes being printed. The final print didn’t have holes that went all the way through. Unfortunately, I didn’t have any drill bits lying around so I went ahead and heated up a sewing needle and pushed it through the hole. Shown in the drawing below. Thankfully it worked and thankfully I didn’t end up hurting myself. I wouldn’t advise this method unless you know exactly what you’r...