In the last post, I had the bulk of my parts ready and talked about giving them a quick go. With that in mind, today’s mission was to build as basic a quadcopter as possible and see how well it performed!
How it works
This model is as basic as you can get; all I want to do is wire the motors to a battery, with not even a switch, and see if it achieves lift. It won’t be pretty, it won’t be stable. But it will tell me if the battery, motors and rotors will get the whole kit-and-caboodle off the ground.
Constructing the frame
My first objective was to make a static frame that could hold the motors (and rotors) still. A set of disposable chopsticks proved ideal; I marked out the half lengths of the rotor, then a 1cm space, the diagonal length of the Altoids Smalls and then another 1cm space and other rotor halves on each chopstick. I then chopped the chopsticks down to end at each rotor mid-point, as shown below.
I angled the chopsticks to match the corners of my Altoids tin and marked where they crossed. This allowed me to file away the marked areas, enabling the chopsticks to cross one another flush. These were stuck together and then taped to make them sturdy. Next, I stacked the ends I had cut off onto the ends of the cross, stuck them together with an adhesive roller (like a sticky tippex) and then wrapped them in sellotape. The sellotape would provide a flat, vertical surface on which to stick the motors.
The wiring assembled was very, very simple; one end of the battery connected to one terminal of each motor, while the other end of the battery connected to the other terminals. To do this, I cut 5 yellow lengths of wire and 5 black lengths of wire, all of roughly equal length. I essentially needed a star configuration as shown by the yellow wires.
The ends were stripped, with one end stripped twice as far as the other on each wire (extra contact for twisting together). I twisted the wires into pairs, then weaved the pairs together along with the fifth wire and twisted the lot together. If you try this, soldering the wires shouldn’t be necessary as long as you twist the wires really tight with pliers. My wire of choice is single-core, because it retains its shape after you twist it.
You can see here all the parts ready for assembly. I stripped down my servos for the motors but left the connectors on for now. That way I can just push the wires into the sockets.
The first step was to arrange the wires onto the frame. Each fan of wires was arranged into a cross with one wire stuck up. Then the two were placed onto the frame in the middle and stuck down. VERY IMPORTANTLY, I made sure that the yellow and black wires DID NOT TOUCH, because that would directly short out my battery and probably catch fire.
To wire the motors to the wires, I simply inserted a yellow wire and a black wire into the terminals of each motor, taping them if they refused to stay put. Because one pair of my rotors is the reverse of the other, I connected the yellow to yellow at the front, but then yellow to blue at the back. That way the back motors spin in the opposite direction to the front, making all the rotors push air downwards. Here are the motors wired.
To stick them in place I first stuck them to the sellotape with the adhesive roller tippex thingy, further securing them with sellotape wrapped around the sides.
Finally, the battery was taped under the middle of the frame to secure it. Before connecting it, I shortened the exposed sections of the wires as much as possible to minimise them touching when plugged into the battery, thus minimising big boom later. Here is the finished result.
P.S. – Upon revision I would definitely place my battery wires down to save my fingers from the wrath of the rotors, so just keep that in mind. I know I will.
Well, it didn’t fly but I had great fun and in one day got a real feel for how the drone needs reworking. I now appreciate how heavy my motors and battery are combined. I’ve learned that quadcopter is the way to go; I’ll need all that thrust, plus it easily solves the issues of steering without adding excess weight and not spinning from an imbalance of momentum in the rotors. It did make a good hover above the table, so I know that I’m not far off what I need, but alas I either need bigger rotors and either a more powerful or lighter battery.
Have fun with your build and let me know how your trials and tribulations go, or what you think of this build.