DIY 3” Quadcopter

A Sub-250g DIY drone. Capable of FPV, 3-4S batteries, with 1407 motors and a 3” toohpick frame. This build came out to be around 248g with the battery.

Design Constraints

The primary constraint for this project was the weight requirement. When a drone is under 250g, it is subject to less regulation from Transport Canada and is generally safer to fly. I would need to carefully research how much weight each component on the quadcopter weighed. This includes all the functional components and screws.

The configuration I decided on was to use a small frame and build, where the total weight without the battery would be around 70g. This is without any screws or additional wiring so it was a good start. The battery itself was a 4s 1300mAh LiPo battery, coming in at about 150g when fully charged. The controller board was also an All-in-One board, meaning that it had the 4 ESCs, PDB, and FC on the same board. This drastically brought down the weight and complexity of the quadcopter.

Mounting hardware

As each component was not standard to the chosen frame, I had to design some lightweight mounting hardware to both secure and protect components.

For the camera, a box where it could be slipped into was designed and printed in PLA.

Intial ideas had components being mounted under and over an adapter plate, while the plate was mounted to the frame.

This proved effective for keeping weight down and heat dissipation but left components very vulnerable. I looked for a solution that had the FC and radio reciever enclosed to be protected from crashes and such. I came up with a sort of stacked “cage” that protected the main components. This added about 10g to the final build.

After all the sodlering had been done, I also printed out a battery protector, found here: https://www.thingiverse.com/thing:2256553 . The build was completed by early June 2021, and was extensively flown in August 2021. An issue I came across were the solder connections of the motors to the board. These connections came loose during an outdoor crash since they were slightly exposed from the cage.