Joshua Bardwell, YouTube FPV drone builder

• body or frame, usually made of carbon fiber
• 4 motors and 4 props
• 4 motor controllers, required by all DC brushless motors
• ESC
• flight controller
• radio receiver, with antenna
• GPS module, with antenna, optional compass aka magnometer
• video transmitter, with antenna

• body, frame, usually carbon fiber
• 4 motors
• 4 props
• 4 ESC's
• Flight Controller (FC), an Integrated Circuit
  • usually includes sensors
    • 3 accelerometers, to detect linear motion on 3 axes
    • 3 gyroscopes, to detect rotational motion on 3 axes
    • compass (optional)
• GPS, antenna, compass
• Companion Computer, optional
• video camera, transmitter, antenna
• telemetry transmitter, antenna
• RC receiver, antenna
• battery
• payload (optional)
• feet or landing gear
• power distribution bus

Ground station

• goggles or display
• Radio Controller (RC) “radio” with transmitter

diagram
https://www.pinterest.com/pin/531495193507157141/

• GPS
• Magnometer/compass
• Barometer/Alimeter, detects height above sea-level
• Accelerometer, detects linear motion along an axis (x,y,z)
• Gyroscope, detects rotational motion around an axis (x,y,z)

Note. There may be two compass/magnetometers, one on the flight controller, and another on the GPS. You must configure the fc, the fc firmware, and inav, so that everyone knows which compass we're using.

The GPS is installed on the top of the vehicle so it's antenna is open to the satellites.

The compass/magnetometer must be installed at a distance from metal and electronics which can interfere with it's operation.

Jumper T16 multiprotocol radio transmitter.

Open TX - the software OS that runs on the radio transmitter.

TX Companion software runs on a PC. You can plug your radio transmitter into your PC and change settings from the PC.

Setup model. Can fly multiple aircraft with one controller. Setup a model for each drone.

Taranis, made by FrSky, used by, but Not recommended by, Mr. Steele.

The transmitter is often a separate add-on board within the RC.

2.4 GHz, most common frequency. 900 MHz is used by Mr. Steele as it has longer range and less susceptible to obstacles.

Crossfire made by TBS, the current state-of-the-art transmitter, because of its long range. 900MHz.

You have to buy a receiver for each drone specific to the RC. Companies sell the RC cheap and make profit on the receivers.

TBS Tango II, $160, Crossfire built-in, battery built in, USB-C charging, recommended by Mr Steele.

Velocidrone, $20, windows

Game simulators, with moon gravity.

• DRL drone racing league
• DCL drone championship league, European version of DRL
• Liftoff, on steam

Firmware to flash on to the flight controller, using a PC.

• Betaflight - for racing
• inav - for autonomous flight

inav configurator software runs on PC, Mac, or Linux. Allows you to flash the flight controller and then change the settings.

A serial port, similar to USB port on a laptop

The flight controller has multiple UARTs. The pins of a UART can be a jack, or solder pads, or both.

We use the UARTs to connect the GPS module, the radio receiver, and other components.

The UART is a serial port. It has 5 pins:

• power,
• GND - ground,
• ?,
• TX - transmit
• RX - receive

TX on the periperal connects to RX on the host, and vice-versa.

GCS ground control station

What is the difference between GCS and RC transmitter?

• CMOS or CCD
• Complementary Metal Oxide Semiconductor (CMOS) most common.
• Charge Coupled Device (CCD). More expensive, greater power consumption, higher quality image.
• PAL vs NTSC

Camera vs sensor. Camera includes a sensor plus image processing hardware/software. That's why a sensor image is black and white; the color correction is image processing that happens in the camera.

Mounting size

Mounting hardware. Sticky tape or stack mountable.

They get hot. Sometimes equipped with heat sensor and automatic shut-off.

Input voltage capability. 5v or more. Wire to the battery correctly so as not to smoke the vtx with too much voltage.

Power output in milliwatts. 25 to 800. Lower can be better. For racing, lower power reduces interference. In an area with trees, building, and obstacles, a “multipath” environment, the high power signal gets bounced around, interfering with itself. Otherwise greater power gives more range. Switchable (choose this) between 25 and 800.

Connectors: power, antenna, wiring.

Antenna connector.

• uf.l, small and light but comes loose. Reinforce with glue, tape, zip ties. Never run transmitter without antenna attached; it acts as resistor to drain the power load.

• mmcx, stronger but bigger and inflexible. Takes up space on frame.

• SMA. Biggest. For bigger long range antenna. Looks like coax, with center pin.

Wiring connector. From FC or camera. Plug or solder pads.

Power connector. Take power from FC or direct from battery.

Frequencies.

• Band and channel. 8 channels per band.

• 40 channels but only a few commonly used. Only eight people in the air at a time to avoid interference. Tricky to choose band and channel to avoid interference.

• Race band. (Choose this) 8 channels, low to high, good separation, no interference. Numbered 1 thru 8 so you don't have to memorize frequencies.

Smart audio or tram protocol. Allows you to change the channel from your RC. Without it the vtx will have button and LEDs.

Antenna.

• Dipole. Small, common.
• Right-hand circular polarized. Pagoda or AX2. Longest range. Requires bigger SMA connector or adapter.
• Cloverleaf. One type of right hand circular polarized.
• Omni vs directional.

Recommended. Matek Sys. https://m.youtube.com/watch?v=0AKBNyJ4dTg

Diversity. Use two receivers and let a microprocessor flip back and forth to the one with the best signal at any moment. Often one receiver will have an omni-directional antenna and the other will have a uni-directional antenna.

Auto-Scan, an increasingly common feature on VRx units that allows the user to scan through available channels to find ones that are in use.

• Camera, transmitter, antenna on the drone.
• Antenna, receiver, display on a ground control station (GCS) or a pair of goggles.
• Frequencies. Most common: 5.8 GHz. Divided into bands and channels, eight channels per band.
• RF radio frequency.
• Analog. Most common. Compact, low cost. Real time, no latency, no compression or processing required.
• Digital HD. Expensive processing required to bring latency down to acceptable levels.

• Video formats ?
• Compression ?
• Does every camera work with every display?

Camera, TX, RX bought separately, used together: https://youtu.be/PrQYdr8GgLY

=== Flight Controller (FC) Hardware

History of ArduPilot hardware.

Eventually Arduino was made to run on the Pixhawk board, and the Arduino hardware line was discontinued.

Pixhawk Navio2

=== Flight Controlleer (FC) Firmware

Arduino - made by the Arduino team PX4 - made by the Pixhawk team

Both ArduPilot and PX4

• use MAVLink middleware for communications
• offer high-level API's so programmers can control the drone in language of choice
• popular API
  • for AuduPilot: dronekit
  • fox PX4: MAVSDK

=== Companion Computer

• Raspberry Pi
• Nvidia Jetson Nano
• Nvidia Jetson TX

https://dojofordrones.com/ground-control-stations/

Mission Planner

MAVProxy - send MAVLink packets over IP, no, evidently MAVProxy is a command-line GCS software package developed by CanberraUAV in 2012, written for Python 2.6

QGroundControl

=== Middleware Communications Protocol

MAVLink - used by both ArduPilot and PX4

python wrapper around MAVLink http://mavsdk-python-docs.s3-website.eu-central-1.amazonaws.com/plugins/camera.html

Sky-Drones SmartLink

• evidently works only with Smartap GCS
• All three sets of data handled in one device
• Air Unit and Ground Unit.
• Ground Unit connects to laptop via USB.

connect to ip addr and port

• a very large number of simultaneous connections are possible
• in a typical scenario, one drone is connected to one GCS

but,

• a GCS can talk to multiple drones
• one drone can connect to another drone
• multiple GCS's can connect and work together

a port is a socket

sockets programming, all languages, all os's

example python opening sockets

Each drone will have three ports, one for each type of data.

• video stream, from drone to Ground
• telemetry stream, from drone to Ground
• commands, from Ground to Drone

Ways to use video

• not at all. Drones don't need a camera.
• record onto a memory card
• send to a companion computer for realtime pattern recognition
• transmit to a pair of goggles for FPV flying
• transmit to a GCS for display, analysis, and navigation decisions

Four pieces of video equipment for FPV:

• camera
• video transmitter (vtx)
• video receiver (vrx)
• goggles

In 2015, the systems were analog, and the video receiver was sold separately, and would attach to and plug into your choice of goggles.
2015: https://www.youtube.com/watch?v=PrQYdr8GgLY
2016: https://www.youtube.com/watch?v=CBmkRtDM_Yc&t=0s

In 2022, new digital systems are available from DJI and from FatShark/Walksnail.
These come with integrated receiver/goggles. You cannot buy the receiver sseparately.