Week 4: The Waiting Game

Ah! Hello again. Let’s play the waiting game, shall we?

My drone components are still shipping, so I’ve had to focus on preparing all of the other components so that I’ll be ready to fly in no time once the motors, propellers, batteries, and power distribution board arrive at my doorstep.

A large focus of my project is building a drone from the ground up, meaning I need to fabricate a majority of the components myself while keeping cost-savings and weight-savings in mind. Over this week, I’ve been engineering the hardware that the drone will operate with. I began with a main chassis which has 4 slots for the carbon tubes to fit into. It’s structurally reinforced using large blocks with high infill. After 3D printing the version 1 chassis design, I fitted the carbon tubes into it and did some stress-testing. To me, stress-testing simply means putting as much force as I can on each tube while isolating the others to ensure the frame can withstand high forces that may be observed during a crash or rapid acceleration. In the end, the 3D printed chassis broke. Time to go back to the drawing book!

In addition to designing the chassis, I’ve come up with an innovative system to mount electronics. I call it The Sandwich. It’s modular, simple, and space efficient. Basically, it uses a 3D printed plate with spacers which is then mounted to another 3D printed plate. In the space between these plates, there’s room for electrical components (like the power distribution board and batteries) with holes for wires to pass through for cable-management.

A huge problem with DIY drones is their instability. Because many parts are custom fabricated, there may not be the structural balance that a tried and tested platform may provide. I must keep this in mind when mounting components to the chassis. Without structural balance, vibrations are to be expected. These vibrations can be critical to the control of the drone as violent movements can confuse the Pixhawk flight controller which uses gyroscopes and accelerometers to stabilize flight. My solution to this is a damped platform for the flight controller. I designed a platform that stands on rubber dampers so that impacts are absorbed before reaching (and confusing) the flight controller.

I learned to do this from a critical mistake on my first DIY drone, which yawed uncontrollably upon takeoff. This week, I also spent some time parting out that drone. I removed the flight controller and electronic speed controllers (ESCs) so that I could use them on my new design.

And with that, Week 4 is a wrap! Thank you for reading, and keep an eye out for next week’s blog where I’ll make advancements in both the hardware and software to prepare the prototype drone for its first flight.