Introduction: TERMINATOR: a Do It All Drone!

Did you ever wish you had a drone that could do everything you dreamed about?

This quad can do all those things and much more!!!

It can travel the way you want it to, admire scenery from above as you wish it to, or give you a disco lighting system from 30 feet above ground and much more!!!

In this instructables, you will be able to build a quad from scratch which can do all these things !

Step 1: Parts, Specifications and Price List

  • Frame manufacture
  1. Carbon Fibre sheets (250 gsm) (,
  2. Glass Fibre sheets (200 gsm) (,!/fabric-and-reinforcement/glass-fibre-reinforcement/woven-glass-fabric/light-weight-200g-woven-glass-fabric.html)
  3. A grade Balsa, 5mm thick (
  4. Hardener
  5. Resin
  6. Dye
  7. Hollow Carbon Rods, 5mm diameter (,
  8. Hex and Round Spacers (
  9. Aluminium I section Beam
  10. Wheels

Step 2: Basic Design of the Quad

First, the basic design of the frame with dimensions needs to be done with at most precision. Frame is one of he major components which dictates the stability of a quad. When designing a frame, lot of parameters like centre of gravity, moment of inertia, torque experienced on arms, stress on frame, shock loads on legs etc... must be considered.

This is an H quad. It has two Arms at its ends and a mid-frame which houses all the equipment. An H quad is preferred as it provides a lot of space in the middle to hold different components for different functions even though balancing the quad is difficult.

As the components are mounted in the mid portion of the quad, length of quad must be more than its width. Motors are placed at the ends of the two arms, hence arms need not be wide, but their joints with the mid frame must be extremely strong so that it doesn't bend due to the torque produce by the motors.

The mid-frame consists of Pixhawk, Telemetry, Receiver and GPS on the top frame; Battery and four ESC's are housed in between the top and bottom frame; Gimbal and sonar are on the bottom frame. Length and Width of the frame must be decided first. It must be sufficient to hold all the required components without increasing weight of the quad, and there must be enough clearance between two adjacent propellers so that they do not cause interference between themselves.

Step 3: Frame Manufacture

So, designs and dimensions of the entire frame of the quad is done. Fabrication of all these parts and assembling them is the next major step in building of this quad.

Materials needed for fabrication of composites:

  • Carbon Fibre
  • Glass Fibre
  • Carbon Rod
  • Resin
  • Hardener
  • PVA (Poly Vinyl Alcohol)
  • Dye (any preferred colour)

These are the common points followed while doing a Composite:

  • Amount of resin (By Weight) =
  1. Total weight of composite, (Carbon Fibre + Glass Fibre) if it's a Carbon Fibre - Glass Fibre Composite
  2. 1.5 times the total weight of composite, (Balsa + Glass Fibre) if it's a Balsa - Glass Fibre Composite
  3. Total weight of composite,(Carbon Fibre + Carbon Fibre) if it's a Carbon Fibre - Carbon Fibre Composite
  • Ratio of resin : hardener = 10 : 1 by weight.
  • A drop of dye of the preferred colour is added to Resin - Hardener mixture to get the desired colour.
  • There are two ways of aligning Glass/Carbon Fibre sheets-
  1. Parallel (All fibres are parallel to each other and also to the edge/side of the sheet)
  2. Diagonal (All fibres are parallel to each other but make an angle of 450 to the edge/side of the sheet)
  3. First layer laid is always parallel and then a diagonal layer is laid and consecutively layers are alternated.

Step 4: Frame Assembly

In order to make the entire assembly of the quad, Joints are to be done between different components of the frame. For the purpose of joining two parts of the frame: Nylon screws, Lock Nuts, spacers and bushes were used.

Joints are to be done between:

  • Arms and Top plate of the mid frame
  • Arms and Bottom plate of the mid frame
  • Two Landing gear composite sheets and a wheel
  • Arms and Legs/Landing Gears
  • Spacers between Top and Bottom plate of the mid frame.

Holes are drilled at the appropriate places on Top plate, Bottom plate, Arm and Landing Gear.

(Detailed Frame Assembly is given in PDF)

Step 5: Choosing the Right Product and Electrical Calculations

To choose the type and version of component which has to be bought. First current, voltage, Power and other relevant values need to be calculated. For this purpose, circuit is first analysed taking all the necessary precautions and following few common steps.

So, first these simple connections need to be done:

  • +ve and -ve terminals of the battery must be connected to +ve and -ve terminals of all the four ESCs, so these four ESCs must be connected in parallel to the Battery.
  • Each ESC must be connected to one motor (containing a propeller).
  • The three wires of a ESC are connected to the three wires of motor irrespective of order of connection. To change the direction of rotation of a propeller, simply interchange any two wires out of the three which are connected. This changes the direction of rotation of motor as these are 3 Phase motors.
  • Signal wire from each ESC is connected to pixhawk and all the necessary connections to Pixhawk are done.
  • Pixhawk connections include, Telemetry, Receiver, GPS, Buzzer, Switch, Gimbal and Sonar and any other extra connections if needed.
  • Based on the calculated values and appropriate fluctuations accounted for, we need to select the brand and type of Motor, Esc and Battery needed. So by approximation, we can assess the weight of the complete quadcopter based on the components used.

(Detailed calculations are given in PDF)

Step 6: Component Placement

Positioning of all the Electrical and Electronic components on a quad is very important. Care must be taken that centre of gravity of the quad is at the exact centre of the frame (where imaginary diagonals of the frame meet).

The four motors (including their spinners), four propellers and four ESC's are placed exactly opposite to each other and hence centre of gravity does not shift due to these components. These components balance each other. So, they are excluded while determining the position of other components.

Now, position of Battery, Pixhawk, Receiver, Telemetry, Gimbal, GPS and Sonar needs to be assigned.

(Detailed component placement is given in PDF)

Step 7: Completion

Thus, after the completion of all necessary connections, additional tuning and Pixhawk calibration is done. These calibration sequences vary for each and every Quad. It is also necessary to employ different methods of tuning. The calibration values obtained would thus be of little use, and must be aptly calculated for the final quad by testing rigorously. With the existence of unprecedented errors, balancing stability of the quad varies. Then the common steps of Transmitter Programming are done. Once these steps are followed and done accordingly, Quad is ready to be flown. But before flying, extensive test flights are to be carried out for further precision in tuning.


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