My project is to add mechanisms to a drone.

  • First mechanism: It is simple, it will only use a ON/OFF signal to start and stop
  • Second mechanism: this would be basically a robotised arm on the drone

So, for realizing this project, I have some questions related to the drone (I do't expect other engineering issues to be adressed here):

  • How to add the command of the mechanisms in the app used to command the drone? I plan to use a drone with a Wi-Fi connection to an app on my phone
  • How to ensure the drone will have enough payload available? It does not seem to be an easy available info in the drone market
  • Has Betaflight any usefulness for such "custom drone" project?

PS: If information is lacking, please tell me


1 Answer 1


Betaflight accepts additional channels from the receiver, on top of the 4 required to fly. Channel 5 is usually used for arming and channel 6 for switching flight modes. Most drone receivers use serial communications when talking to the flight controller, so the hardware doesn't limit the number of channels. Radio protocols commonly have 8, 16 or 32 channels. This is largely just a software option.

Many flight controllers have some output pads for a few of these additional channels. The output signal will be PWM, designed to drive a radio control servo or speed controller. You could use an electronic speed controller (ESC) designed for a brushed motor as a switch. A robot arm would probably use servos.

Most drones don't use wi-fi and phones. They are not really designed for real-time systems. There's a lot running on a phone, and if you wrote an app to control the drone, it wouldn't necessarily have top priority and could pause at an awkward moment if some other piece of software wanted your attention.

Payload is a bit tricky, as only you can decide how much you are willing to sacrifice flight time and agility for additional weight. There are on-line calculators for motor and prop performance.

BetaFlight will work for the things I've described above, but you will probably be better served by ArduPilot.


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