A Quadcopter From Scratch: FPV Upgrade

It has been a while since I was thinking about upgrading my drone to a first person view version aka FPV. The idea was placing a camera for video streaming in real time. My first attempt was with a small raspi board and streaming image data from a raspi camera via WiFi. Because of the latency, range, and complicated setup this solution was not very practical.

Therefore, I decided to make a "real" FPV drone.

The jargon and some technical details were explained in the previous post. Before you continue, you may want to read it first:

FPV Components

Part Qty Unit W. (g) Price (EUR)
FPV micro camera 1 8.6* 50.67
Video transmitter (analog) 1 12* 47.92
MMCX antenna 1 3.1 10.23
FPV monitor or goggles 1 - 106.31

* Weight without cables.

Note that you can easily find cheaper versions of those. For instance, a camera and VTX combo can cost under 40 EUR in total.

Basic FPV: Connecting camera directly to VTX

Basic FPV: Connecting camera directly to VTX

Technically these components are enough to build an autonomous FPV system. As seen above, I have connected the camera to the VTX (video transmitter), which was powered directly from a 3S battery (12.6 V). The FPV test flight was successful. Then, I found some space for further improvement. So I experimented with additional components. If you are about to build a quad from the ground up, you may want to consider those. These parts make it much easier to build a new copter.

Optional Components

Part Qty Unit W. (g) Price (EUR)
F4-based flight controller + ESC stack 1 6 + 10* 65.70
Carbon fiber frame 1 107 28.07
Micro receiver 1 1.7 15.76
Pink propellers (5040) 4 ? 11.27

* Weight without connector wires.

The flight controller1 stack gave several advantages. First, a more powerful processor. Second, there was no need in additional UBEC, i.e. the flight controller was connected to the battery. Third, the controller provided an OSD (on-screen display) that could transmit flight information such as battery level or link quality (RSSI, LQ) in real time. I also find it overall convenient soldering VTX and camera wires directly to the flight controller2. And don't forget included silicon vibration dampeners! It is called a stack because of the flight controller and 4-in-1 ESC vertical integration. This implies a standard way to place and connect the two. Besides, the ESC already came with a XT60 connector to solder.

A carbon fiber frame instead of a 3D-printed one is a bit more ergonomic. For instance, it already has standard emplacement for four M2 screws to attach the VTX and a support for the VTX camera. Overall it results in a cleaner, slim build. Commercial frames are strong enough to support a light X-shape, whereas the 3D-printed frame I used previously had a slightly bulky H-shape. Surprisingly, the weight of the new frame was about the same (107g vs 110g). Last but not least the commercial frame was already supplied with a set of screws and standoffs.

The FS-iA10B receiver was quite bulky, so I have replaced it with a smaller one. If you are choosing a transmitter-receiver system, then you may want to consider a long-range TBS CrossFire or ExpressLRS. The last one is cheaper because it is open-source, by the way. In both cases you avoid the problem of loosing the control because of the range. Believe me, I know how it feels bathing a copter in a lake!

F4 controller in a carbon fiber frame

F4 controller in a carbon fiber frame

There was no particular utility in pink propellers, but the older ones were worn out and had to be replaced anyway. The four motors, batteries, the radio transmitter, "velcro" fasteners, and motor-antivibration pads were taken from the previous build. There was no separate UBEC part anymore.

This is how it feels to fly analog FPV. Signal interferences are visible, but the latency is only 6ms!

And here is a video:

What remains now is to mount a GoPro camera on top for high-resolution images.

Learn More

  1. Powered by Betaflight software. ^
  2. A pro tip: They recommend twisting the wires to reduce the interference. ^