Working at Drone Dudes was one of the best experiences of my life. The Gryzzl Drone was a project for Parks and Rec. They wanted an Amazon Drone style delivery drone capable of delivering a box to your front door step.
I first learned about the project on a Wednesday. I had a lot of work to do but I knew I could complete the project. 3D printing was getting popular and I had past experience designing parts suitable for 3D printer capabilities.
Carbon fiber tubes, 3D printed ABS plastic parts, and basic M3 bolts and nuts would comprise the majority of the hardware for the box delivery mechanics. The electronics was relatively simple, only two servos required. I would find out later that I had discovered what a ‘cam‘ is in trying to interface the servos with the box delivery arms. More on that later!
Wednesday night I quickly designed a calibration part for the carbon tubes I was going to use. From my past experience with 3D printing I knew designing parts exactly to fit didn’t exactly work. I needed to know what the difference would be from what I designed vs what would come out of the 3D printer.
On the left is a rendering of what I designed. A simple cube with all the features I might need during my work on this project, it was a true test of the printer’s capabilities. On the right, what came out of the printer. The 25mm diameter hole actually split when I pushed a sample piece of carbon tube through it. I hot glued it back in place and measured about a 1mm gap. 26mm diameter holes for 25mm diameter carbon, check! Next was the overhang capabilities and minimal print areas. The archs on the bottom show that a) the overhangs wont be a problem and b) the two small squares at the base of the middle arch can be printed OK and will not slop over the sides.
Now came the difficult part, actually designing the mechanics for a box delivery system. My first inspiration came from the first Amazon delivery drone service video they released back in like 2013. I downloaded the video from YouTube using a service like KeepVid and made a looping gif of the clip showing the latching mechanism they used. ImgFlip makes this process really easy now;
The plan was to use the tripod landing gear from one of our Movi gimbals. After removing the gimbal itself, I was left with a good frame for a box delivery mechanism with plenty of room for a smaller size pelican case underneath.
I think Amazon has probably improved on the ‘box fingers’ design since they first released this video, but this design was good enough for what I needed. It took me about 20 hours to get my original design put together;
With 23 pieces, the guy doing my 3D printing was up day and night for about 4 days getting the pieces made for me. I paid him a lot for all the work and he did a really amazing job. I had three design iterations during the project and both times he was able to accommodate my busy schedule. Aside from print quality, organization and keeping track of all the parts was very important. I exported each part into a different STL file with a ##.stl style filename. If I needed two of any part, I would use two identical STL files with the part number for the name. This way, he knew to just print one of every part I sent him and put a small piece of tape with the part number on it to keep track. For the few pieces I had to revise, I would create a new part number to keep things simple for him.
The metal inserts seen in that part labelled ‘2’ are M3 threaded hexagonal standoffs. By printing the correct size cavity, a riser can be pressed into the cavity to provide metal threads. A second 3D printed part with holes in it can be bolted onto this part, clamping a carbon fiber tube in between.
The mechanics for the arm are pretty simple. Two spring pull each arm inwards, clamping the fingers (not pictured yet) against the box. The servos on top rotate a cam that presses against the top part of the arm, pressing it outwards and releasing the box.
I had difficulty finding the aluminum rod. I got really lucky finding a metal supply shop really close to our studio that had every shape and size of different stock metals. I took the bearings shown in the photo above and found some rod that fit perfectly. I think they charged me about $4 for a bunch of different cut lengths of the rod!
A closer look at some of the clamping action holding everything together.
It all came together nicely once the movie studio brought the logo’d parts to our studio. They did a great job of painting the parts and printing their logos on the cover and the delivery box.
Some close up shots of the actual box delivery mechanism;
If you look closely, you’ll see that the two metal rods are different colors. One is aluminum, the other is untreated steel. Its brown color is from oxidation (rust) from being exposed to air. I had to use steel because it was what the metal supply shop had in stock that was exactly the right size to fit into those bearings.
And finally, some pictures from on set!
Thats me on the right!
It worked! They filmed three different scenes with us and the one that made it into the final cut was the opening to episode 5 of season 7! I’m really stoked that my work has been seen on Netflix!!
Thanks for reading!