Intro: Make Your Own Mini Quad Copter
A local school needed help with building a quad copter. They had bought the parts separately from Banggood at a good price but they sadly came with no instructions.
Here is a parts list (as far as I can determine from the packaging)
I had built my own quad copter and felt up to the challenge. After Googling some of the part numbers of the receiver, I determined that they were to make up a Hubsan H107 X4 RC Quad copter. Using this helpful link https://www.instructables.com/id/Cheap-flying-Lego-quadcopter, I was able to learn the motor connections.
The next task was to find or make some kind of base for the components. I decided to use an old CD-ROM case, cutting off the middle post. The well in the middle seemed ideal to house the receiver. Next I drilled 4 holes on the rim, just large enough for an interference-fit with the motors.
The motor wires were not long enough to reach the receiver so I added some short extensions. I had, in the meantime, been charging the little motor battery, which took 30 minutes approximately, using the supplied USB charger. Its LED turns on whilst charging and turns off when fully charged. I measured the voltage after charging and found it to be 4.18 volts.
Next, I put the blades on the motors and was ready to do some tests. I first turned on the transmitter, and its LED turned red. Then I connected the battery to the receiver and its two blue LEDs flashed alternately briefly then stayed on, simultaneously the LED on the transmitterl turned green and there was a little bleep to tell me that they were connected.
I then raised the left-hand lever to increase throttle and all 4 motors started spinning. Then I noticed that the blades were turning in the wrong direction, so I powered off and swapped the blades over. The correct layout is as follows: Motor 1 should be counter-clockwise, Motor 2 clockwise, Motor 3 clockwise and Motor 4 counter-clockwise. The motors are numbered 1, 2, 4 then 3 when counted in a clockwise direction around the receiver as viewed from the top.
Having swapped the blades, I tried again. The craft barely got off the ground a full throttle. At this point I decided that the CD-ROM case was too heavy and mostly preventing the flow of air up into the blades. I then used a hacksaw and craft knife to remove most of the case except for an X shape.
This proved successful and I was able to fly the craft, see video below (MiniQuadCopter.wmv). It is very lively and responsive and my flying skills leave a lot to be desired. The remote control also will probably need to be trimmed using the little push-buttons beside the joy-sticks. Some research is needed to find a lighter material and easier way to mount the motors and flight controller. All in all I found it to be a rewarding task and hope the students get as much fun and satisfaction building their own.