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Simplest Quadcopter Drone Circuit

The post delineates a simple quadcopter circuit or a drone circuit which can be built by a layman and operated using an ordinary RF remote control module. The idea was requested by Mr. Sahaj

quadcopter correct propeller direction of motion simulation

Designing the Quadcopter


In this post we learn how to make a quadcopter or a drone quickly and cheaply using very ordinary components. In one of my earlier posts we learned how to make a relatively complex and therefore efficient quadcopter flying machine without using microcontroller, for more info you would want to go through the following posts:

Building a Quadcopter - Basics Explained

Quadcopter Remote Control Circuit without MCU | Electronic Circuit

In the present article we try to make the above design much simpler by eliminating the brushless motors and replacing it with brushed motors, and consequently making it possible to get rid of the complex BLDC driver circuit module.

Since the mechanical construction details of the quadcopter was already discussed comprehensively in the earlier post, we will only deal with the circuit design section and learn how it may be built for flying the proposed simplest drone circuit.

As mentioned earlier this simple quadcopter requires only the basic RF remote control modules as shown in the below example image:



You will need to buy these RF modules from any online store or from your local electronic spare dealer:

Apart from the above mentioned RF remotes modules 4 permanent magnet brushed motors will be also required which actually forms the heart of the drone machine. It could be as specified in the following image with the given descriptions, or any other similar as per the required user specifications:




Electrical Specifications of the Motor:

12V = operating voltage 200mA = operating current 10,000 RPM

How to Configure the Remote Control Receiver with the Motors


Before understanding how to configure the remote control receiver with the quadcopter motors, it would be important to learn how the motor speeds are supposed to be adjusted or aligned for generating the required left, right, forward, backward motions.

Primarily there are two ways a quadcopter can be enabled to move, which are in the "+" and the "x"modes. In our design we employ the basic "+" mode of motion for our drone, as indicated in the following diagram:

quadcopter movement directions in response to motor fast slow PWM


Referring to the above diagram we realize that we simply need to appropriately increase the speeds of the relevant motors for executing the desired directional maneuvers on the drone.

This increase of speeds can be enforced by configuring the remote control relays as per the following wiring diagram. In the diagram below we can see an IC 555 PWM circuit wired with the 4 relays of the remote control receiver module of the 6 relays (1 relay being unused and could be simply removed to educe space and weight).

Adjusting the PWM


As may be witnessed in the diagram, the PWM feed is connected with all the N/C contacts of the relays, which implies that normally the quadcopter would be hovering through this uniform and equal PWM feed, whose duty cycle may be initially adjusted such that the quadcopter is able to attain a correct specified amount of thrust, and altitude.

This may be experimented by appropriately adjusting the shown PWM pot.


How to Configure the Relay Contacts




The N/O contacts of the relays can be seen wired directly with the positive supply, so whenever a relevant button is pressed on the remote transmitter handset, the corresponding relay is activated in the receiver module, which in turn enables the relevant motor to get the full 12V supply from the battery.

The above operation allows the activated motor to gain motor more speed than the rest of the motors which consequently allows the quadcopter to move towards the stipulated direction.As soon as the remote button is released, the drone stops instantly and continues to hover in the constant mode.

Identically, other directional motions can be simply achieved by pressing the other assigned buttons, on the remote handset.

The topmost relay is for ensuring a safe landing of the machine, this is done by adding a current dropping resistor in series with the N/O contact of the shown relay.

This resistor value must be calculated with some experimentation such that the quadcopter hovers around a couple of feet above the ground whenever this resistor is toggled through the attached relay.

Circuit Diagram


Simplest Quadcopter Drone Circuit


The shown relays are the part of the RF module receiver, whose contacts are initially unconnected (blank by default) and needs to be wired as indicated in the above diagram.

The RF remote receiver is supposed to be installed inside the quadcopter and its relays wired with the relevant motors and battery as per the above shown layout.

How the Drone Moves:

As explained in the above discussion, when a particular remote button is pressed, it actuates the corresponding relay of the quadcopter module causing the relevant motor to move faster.

This operation in turn forces the machine to move in the direction opposite to the motor which is being switched to rotate at the faster RPM.

Thus for example, increasing the speed of the south motor causes the machine to move towards north, increasing the north motor causes it to move south, similarly increasing east motor speed causes it to move west and vice versa.

Interestingly, increasing the south/east motors enables the quadcopter to move towards the opposite north/west that is in the diagonal mode....and so on.

Pros and Cons of the above explained Simple Qaudcopter remote control circuit.

Pros

  • Cheap, and easy to build even by a relatively new hobbyist.

  • Does not require complex joystick operations.

  • Can be controlled using a single 6 channel remote control module

Cons


  • Less efficient in terms of battery back up due to the involvement of brushed motors

  • Directional speed is constant and cannot be varied through the remote control handset

  • Maneuvering may not be smooth rather a bit jerky while switching the buttons.



Need Help? Please leave a comment, I'll get back soon with a reply!




Comments

  1. Sir I have a 27 MHz ROC car but i break all the wires of car and transistor circuit now I can't able to join them please tell me how to join motors, antenna and battery to circuit of car
    Can I send photo of my car's circuit any how if u not understand my cars circuit?

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  2. Sahaj, sorry that would be difficult for me, because different RC toys have different wiring configurations, which cannot be judged by just viewing the pictures...

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  3. sir you didnt showed the connection to motor in circuit diagram..can you please tell me online sites where i can purchase motor and rf remote control..iam living in kerala..

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  4. please see the last diagram it has all the details regarding the motor connections with the remote relays

    there are many online stores who sell drone related parts....I cannot specify a particular one...all are good.

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  5. I already found where to join motor and antenna wires
    But still I don't found where to join buttery wire
    Please help me any how

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  6. the ground symbols are all negatives of the circuit and need to be joined with the battery (-).....and the positive of the battery will go to the +12V point.

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  7. Thanks very much I understand where to join -ive wire but still I don't understand where to join +ive wire and also to join the switch wire
    Please reply the good answer I am very thank full to u

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  8. the battery positive will go through a switch and then to the indicated +12V arrow.

    the power ON/OFF switch is not shown, you can add it yourself.

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  9. Thanks very much
    I successfully attached all the wire of car
    But the problem is now my car not going backward
    So please give me the circuit diagram or any idea how to join all the wires in transmitter

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  10. you can refer to the following article for the required info:

    https://homemade-circuits.com/2012/09/make-remote-controlled-toy-car-circuit.html

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  11. HELO SWAGATAM i really like this , am having 9v blushed motors four of them can that circuit above be used if not sir provide me with a circuit where i can use the 9v blushed motor to my simple quadcopter to fly. thanks very much for all your effort

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  12. Hi Davis,if your motors are specified to rotate at extremely high RPMs (3 to 5 thousand) as recommended for drones, then surely you can use them for the proposed application

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  13. the constant frequency maintains constant speed on all the motors which a little lower than the motors full speed, and the drone stays stationery,

    when one of the remote buttons is pressed...the corresponding relay in the drone is actuated which connects the relevant motor directly with the supply and allows the motor to rotate at full speed, this causes higher torque for this motor while the other motors continue with the slower speed...and this in turn enables the drone to move toward the corresponding direction

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  14. please read the previous comment and the article explanation

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  15. altitude will be fixed and needs to be set at the beginning.

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  16. first of all u rocked.......really amazing and good post.....and i am doing this as my semester project but facing some problems.
    Sir, i have a doubt that how and where we are going to connect the relay circuit in the quad copter ...?
    cz as mentioned in this post that the signal will be recieved by RSW434 and after going to HT12D it will be directly connected by 1n1,2and 3 pins of the DRV8313 IC which will rotate the motor........ but where are we going to attach the relay circuit and 555 timer circuit in quad copter as mentioned above ....? kindly help me out ..and please sir kindly send me a full circuit diagram of quad copter cz then it will be easy for me to understand....i will be very thankful..

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  17. I appreciate your enthusiasm, but I think you did not read the article correctly.

    DRV8313 is not used here, the motors are brushed type motors, and are directly connected with the remote relays of the receiver unit.

    Please read and understand the concept correctly before you embark in the project otherwise you might fail to make it work

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  18. Where and how PWM circuit connected to the receiver?
    Thanks

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  19. getting back to new project with in some days jackfranko here

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  20. getting back within some days with new idea will be meeting you very soon

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  21. is it possible to make it with a camera on top??

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  22. hello sir! this seems a really easy and good idea for minor project, can u tell me how much is it going to cost approximately? and how much time is it going to take?and are the components available online ?

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  23. hello sir! this seems as a really good idea for minor idea, can u tell me how much will it cost approximately and how much time is it going to take? and are the components available online?

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  24. Thanks Piyashi,....the cost could be anywhere from Rs.1300/- to Rs.2000/- but it cannot be less than Rs.1300/- for sure.

    all the indicated components can be procured online....however, proceed only if you think you have understood the concept thoroughly and preferably get the assistance from an electronic expert while assembling

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  25. Oh brother, I wish to put our electronic components for the Dron aircraft and the way they are installed and connected to the board or circuit diagram of electronic circuit is very clear and simple to her and the guardian of her own. Thank you.

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  26. Pls Sir I don't understand the Rx in the circuit wot is it

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  27. when this relay is toggled, the 12V supply reaches the motors through Rx, reducing their speed drastically and this quickly brings down the drone towards ground and allows the user to get hold of it.....I am sorry the 12V supply is shown shorted and not through the N/O and Rx contacts...I'll correct it soon...

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  28. Sir I am interested to make a quadcopter with mini motors in the mobile phones.
    Is it possible??
    If possible what changes I could make in the circuits you explained.
    Please answer me....
    I am waiting for you.

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  29. hai sir I am Akhil
    I am interested to make a quad copter with mini motor in mobile phones.
    Is it possible??
    If possible what change I could make in the circuits you mentioned.
    Please replay me with details.
    I am waiting for your response.

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  30. Hi Akhil, I don't think that would be possible because the motor may not have the required amount of thrust to lift the circuit board itself, especially due to presence of the relays.

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  31. Then which type motor can be used to make a small size quadcopter.

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  32. It should be big enough to at least be able to lift the circuit boards.

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  33. From which site i can buy rf remote control module?

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  34. search for "buy 433MHz Remote control module"

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  35. I needed the complete diagram and step to step of soing it, this way it will be more easier for me to build.

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  36. hey swagatam. i'm interested in your projects.keep teaching us

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  37. hey swagatam.thank you for your projects.May you teach us how to make a wireless computer controlled quadcopter please?

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  38. Thank you David, the idea that looks a bit complex and beyond the range of my expertise, still if possible I'll try to figure it out.

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  39. Thanks.Is there any problem using a higher rpm motor like a 20 000 rpm?what change can it make on it's capacity to lift objects like camera?

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  40. yes that's definitely possible, if the thrust to weight ratio of the motor is sufficiently high. No changes would be required in the design, just the battery will need to upgraded according to the motor's current rating

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  41. Thanks.Is there any problem using a higher rpm motor like a 20 000 rpm?what change can it make on it's capacity to lift objects like camera?what is it's maximum altitude and according to you what will be the good value of Rx

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  42. The lifting power will depend on RPM, propeller size, and the motor current, and its thrust to weight ratio (efficiency). The circuit will not any changes for this upgradation, as long as the motor current is not above 3 amps. in that case the relays will need to be accordingly upgraded.

    Rx value will need to set with some practical experimentation.

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  43. Can it be possible to add a wireless 600g camera to the quadcopter?

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  44. Using brushless motor can make any change?

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  45. brushless motors will require special drivers, that's the reason brushed motors are not employed here for the sake of simplicity.

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  46. how can i attach a non wireless camera to my drone

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  47. first test the drone in its basic mode, test its lifting power and then you can try loading a camera...

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  48. Can we use the same for small rc plane if yes please let me know it will be very helpful of you as I want to make a rc plane and I am not an engineer but highly interested in making rc plane my using mentioned circuit diagram.

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  49. An RC plane may be quite different to a drone and much complex than a drone, a drone is very straightforward to design and build but an RC plane may not be that simple, sorry I do not have sufficient data with me to assist you in building an RC plane.

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  50. what size an weigt of battery will a simple drone lift

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  51. any appropriate Li-ion or lipo battery will work, these are already well optimized.

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