A 65cm square frame was chosen to get space for the sensors between the rotors.
Next step was to choose motors and propellers to get enough lift for our payload at a comfortable throttle setting, the NTM propdrive 28-30S motor with TGS 12x6 propellers and a 4S LiPo battery.
This would give us enough lift for 3kg of payload at full throttle which means we should be able to fly with 1kg payload at a reasonable throttle setting.
ESCs where chosen to handle the battery voltage and the amperage of the motors, Afro 30A fit these requirements and also runs th open source software SimonK which allows a lot of settings.
ESCs where chosen to handle the battery voltage and amperage of the motors, Afro 30A fit these requirements and also runs th open source software SimonK which allows a lot of settings.
The last step was to choose battery seize and discharge rating to handle flight time and current delivery. We wanted to at least 5 minutes of flight time so we chose a Zippy 8000mAh 30C battery which would give us 6 minutes of flight at full throttle and more than enough current delivery.
Max payload = Total thrust-Weight of copter = 4*1200-1749.2=3050.8g
\end{equation}
\begin{equation}
Fight time = \frac{Battery capacity}{Max amp draw} =
8/80 = 6 minutes
\end{equation}
\subsection{Circuit boards}
We decided to make a shield to distribute all connectors from the Nucleo board base.
The shield board contains connectors to all our peripherals except the LIDAR, because the LIDAR uses Ethernet communication which is already integrated on the Nucleo board.
We decided to use a switching regulator to make a five volt rail for peripherals, because of efficiency when stepping down from 15 volts.
A three volt rail for logic level was needed so a linear regulator from five volt was suitable there.
All power rails and 15 volt peripherals were handled on a separate board to avoid disturbance.
