FPV

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Revision as of 13:07, 25 April 2011 by Ivc (talk | contribs) (→‎Gear)
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Flying electronic RC planes from the ground is fun. Piloting a FPV plane from First Person View is really cool. With the arrival of light and powerful video stream transmitters and long range remote RC transmitter modules , the range of flight has increased from line-of-sight to an order-of-magnitude wider.

Research

To build a reliable platform I want to begin with the fundamental basics and then extrapolate more specific products.

Electronics

  1. Lower frequency will allow greater range, longer wavelength requires larger antenna
    • Higher frequencies, 2.4GHz or 5.8GHz, will quickly get attenuated by the atmosphere
  2. One energy-source, single set of batteries for motor, camera, OSD, VTx, Rx, servos
    • Minimized weight, as batteries contribute as the heaviest component
  3. Receiver antenna diversity for maximum flexibility of the airplane, each antenna 90 degrees perpendicular
    • Omni-directional antennas will have a radiation pattern much like a form of a doughnut, with dead-spots center, above and below
  4. Same radiation polarization on ground station and airplane where possible, alternatively circular polarized ground antenna
    • Signal quality of same polarized electric fields can be many tens of dB different [1]
  5. Parallel 3S 11.1V Lithium-ion Polymer batteries, both on plane and ground station
    • Prevents voltage drop if one cell is bad, might add reverse current protection (diode) to avoid 3S "charging" the then 2S battery
  6. Power- and signal-wiring separated as much as possible
    • Noise from motor can degrade digital signals if coupled with signal-wires
  7. Shielded components, twisted wires, ferrite rings, and condensators will eliminate most noise and oscillation, PCB ground plate facing interference source
    • Minimize both ambient noise and interference from nearby components, think of a long wire as an antenna that will pick up anything
  8. Video-transmitter on a higher frequency band than RC-transmitter, 1.3GHz VTx and 433MHz RCTx, 2.4GHz VTx and 433MHz RCTx
    • Having the same frequency/band on VTx and RCRx will cause signal degradation
  9. Video-transmitter, as well as RC-receiver, powered by 5V voltage from main Lipo-batteries via BEC
    • When the main engine batteries are drained or the ESC unexpectedly shut down, a separate BEC will continue to power the rest of the 5V system
  10. Split aileron servo signal to use twin ailron servos for each wing
    • Prevent loss of control on servo failure, must be mounted close together to drive force-drive the dead servo, might drop this
  11. Proper cooling of video-transmitter using an appropriate heat-sink and thermal-adhesive
    • Powerful video transmitter dissipate a lot of power in form of heat, prevent signal loss

Plane

  1. A wing for speed and stability
    • Makes it possible to fly in windy condition and greater distances, less drag
  2. Batteries in front and electronics behind the batteries, suitable motor to create enough lift
    • Front heavy for stable dives when motor is inactive and in up- or down-drift
  3. Find the center of gravity by temporarily putting everything where they're supposed to go
    • Makes it easier to find where the sparing bars between the wings will go and position of the motor mount, leave the battery location to last for fine tuning CG
  4. Motor mount on or close to the center of gravity
    • Easier to handle during acceleration and less wobbly when the force is pushing the center instead of the back end, imagine a horizontal axis over the wings as center of gravity
  5. Keep the servos, transmitters, and battery packs as near the center as possible
    • Makes the flight more stable in windy conditions, instead of wobbling back and forth because of inertia
  6. Antenna for VTx mounted at the end and center of the left-wing, while the two RC-receiver antennas on the other right-wing, shifted 90 degree
    • Minimize interference between the two radio systems, 90 degree angled to allow cross-polarization, both vertical and horizontal for better signal quality at different plane orientations
  7. Servo location as far forward as possible to put center of gravity back
    • Push-rods on an angle does not affect the elevator action, might put but more pressure on the servo [2]

Gear

Use this as a guide to ballpark what is needed and then just pick whatever falls inside your needs and specifications.

Video system

Cameras

Preferred voltage is 5V to avoid boost/step-up converters and switching noise isolation.

Recording:

  • GoPro HD Hero - High-definition on-board recording
  • Contour HD - Another HD on-board recorder

Flying:

  • Pixim PX540 - Resolution 540 lines, lower 1/3 brighter, high quality lense, 22 grams, 10-12V [3] [4]
  • DX201 DPS camera - 540 lines, excellent image quality, based on same Pixim sensor as above, 12V [5] [6] [7] [8] [9]
  • Fatshark RCV922 camera - Resolution 420 lines, lower 1/3 brighter, unsaturated colors, 30 grams, 3.3-5V [10]
  • Black Widow KX131 - 380 horizontal lines of resolution, nice colors, value, 23 grams, 5V [11] [12]
  • FPVCAM-480 OSD - Resolution 480 lines, 12V [13]
  • Sony SN555/VSN700 camera - 555 lines resolution, 12V
  • DPC-161 - Cheap, resolution 380 lines, 5V [14]
  • Sony SN777 - 555 lines resolution, 12V, RF noisy [15]
  • KX-171 - 5V, too dark in sunlight [16]

Transmitters

Preferably use 2.4GHz band as it's safer, won't interfere with other, no high powered devices on band, 900MHz overpowered by mobile phones, 1.2GHz aviation communication [17]

  • Lawmate 500mW 2.4GHz Tx - 5-5.5V, 10 grams, use ch5 2370MHz and ch8 2510MHz, outside regular band, noise-free [18] [19]
  • IntelligentFlight GP-707 2.4GHz 10mW micro audio/video transmitter - 1.6 grams, comes with receiver [20] [21] [22]
  • Sunsky 1.2GHz 400mW [23] [24]
  • Sunsky 1.2GHz 800mW [25]
  • BEV 1.3Ghz 800mW transmitter, 12V [26]
  • Immersion RC 600mW 5.8GHz A/V transmitter - Built-in 5V regulator for camera, 6-16V

Receivers

  • Lawmate 2.4GHz Portable receiver - 8 Channels, 5V DC in, small [27] [28] on-board battery [29] [30]
  • RangeVideo 1.3GHz Deluxe receiver - RSSI 0-5V output
  • EagleEyes FPV Station - Receiver with antenna diversity, antenna tracking
  • Immersion RC Duo2400 diversity receiver
  • Immersion RC Duo5800 diversity receiver

Diversity Controller

  • Oracle Video Diversity Controller - Monitors video signal from two receivers (with different antennas), picks the better, opposite of RSSI-based selection [31] [32]

Antennas

A 14 dBi patch antenna has a narrower radiation beam than a 8 dBi patch antenna. A focused 14 dBi yagi for a focus beam in one direction.

  • Active Robots 433 MHz 1/4 wavelength straight and angled - On the plane
  • Maker your own Sander-style omni-directional SMA antenna - Lighter than any purchased item, can be tuned to exact wavelength of frequency

On-Screen Display

  • ImmersionRC EzOSD - Uncluttered display, GPS on-board, signal strength indicator via I2C, current/voltage sensor with Deans
  • Eagle Tree OSD Pro
  • DOSD

Goggles

Resolution is limited by the camera not the goggle, best camera can deliver 480 lines [33], though sensor might state a higher resolution but it's not delivered.

  • Fatshark RCV922 V2 Base Edition - Wide angle 46 degrees, 80-inch on 2 meters, 640x480, adjust for interpupil distance, only the bare minimum video and power inputs required, FPV ground station friendly, 6-12V [34]
  • EVG920 Video Eyewear - Not adjustable interpupil distance, 80-inch on 2 meters, 640x480, 1000 mAh battery, 5V [35]
  • HeadPlay Googles - Not adjustable, 800x600 resolution, requires exactly 12V [36]
  • Fatshark RCV230T/922T Teleporter - All-in-one, limited 320x240 resolution and range [37]
  • Fatshard RCV922 Aviator - Video input, 640x480 resolution, Vin 6-12V [38]

Misc

  • Immersion RC PowerBox - Groundstation video and power filtering box
  • Archos 604 - Video recorder [39]
  • Pinnacle Video Transfer - Video recorder [40]

Control system

Radios

The 35/72MHz radio will not be used, the PPM signal is feed to the long range transmitters.

  • Futaba 6EXP PPM/PCM 1024 35MHz [41]
  • Futaba 9CHP-PCM 36MHz [42]

Transmitters

Connects to any PPM radio via trainer-port.

  • ImmersionRC EzUHF transmitter - 433 MHz frequency band, 200mW or 600mW power-mode, 9-12V prototype model
  • Dragon Link transmitter - Transmits at 433MHz, 500mW [43]
  • Thomas Scherrer OZ2CPU UHF system - Many hardware revisions, hard to keep track

Receivers

  • ImmersionRC EzUHF receiver - 8-channel receiver, signal diversity, 50A current-sensor, 10 Hz GPS
  • Dragon Link receiver
  • Futaba R149DP 72 MHz [44]
  • Corona RP8D1 35 MHz, 4 meter antenna [45] [46] [47] [48]
  • Corona RP6D1 35 MHz [49] [50]

Other

  • ImmersionRC EzAntennaTracker - Uses GPS-coordinates from EzOSD inserted in the right audio channel

Plane

Airplanes

  • Ritewing Zephyr - Foam wing base, glass fiber rods, and winglets [51] [52]
  • Multiplex Easystar - Simple glider-plane [53]
  • ParkZone Radian PNP - Glider, prop in front, huge easy to spot [54]
  • EasyStar - Cross between glider and sport plane, 3-channel, easy to modify [55]

Motor

  • Hacker A30-10L V2 [56]
  • Turnigy 35-36B 1300Kv Outrunner [57] - Great for Maxi Swift [58]
  • Turnigy AerodriveXp SK Series 35-36 1400Kv 550w [59] [60]

ESC

  • Hacker X-55 SB Pro Brushless Motor Speed Controller ESC 55A
  • Turnigy Plush 60A ESC [61] - Great for 4S
  • Turnigy Plush 40A Speed Controller [62] - Great for 3S

Blades

  • Turnigy 10x6 folding blades
  • Aeronaut CAM foldering carbon propellers
  • Aeronaut CAMcarbon Power-Prop 10"x7
  • TGS 10x6F Precision Folding propeller [63] [64]
  • Aeronaut CAMcarbon 9"x7 folding prop blades [65]

Spinner

Servos

  • Hitec HS-645MG [66]
  • Gaupner Servo DES 708 BB MG [67]
  • Turnigy 380MAX Micro Servo [68]
  • Blue Bird BMS-661DMG+HS Super Fast Digital Servo (MG) 6.4kg .08sec 46.5g [69] [70]

Batteries

  • Turnigy S3 2200 mAh
  • Zippy S3 2200 mAH - Cheap Hobbyking packs
  • Flightmax S3 2200 mAh [71]

Charger

  • Bantam BC-6 - Korean, high quality

Materials

  • Laminate - Apply to foam wing to give it a outer strength and cover for paint
  • Riteweave - Flass fiber mesh to add strength over open cuts in the foam [72]

Glue

  • 3M 90 adhesive - Spray adhesive for base to add laminate
  • Zap-a-Gap CA glue - For sparing bars in wings, or Gorilla glue
  • Gorilla glue brown - Glue for wing and sparing bars, activates by adding water
  • Goop - Fasten winglets
  • Epoxy adhesive - Properly fasten the motor mount plate to the surrounding foam

Tape

  • 3M Mailing & Storage tape - Mount elevons to the airframe, 1/3 on the elevon, UV resistant [73]

Shops

Build logs

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