QAV250 Drone Tutorial

Overview:

This page was created as a place to document this project as it was built. Since the original setup a lot of modifications and optimizations have been made which I try to go over and highlight as best I can in the tutorial. One issue with writing a tutorial like this is that there are just so many components that could be made to work for the project, therefor I go over the concepts of how the setup should be be more than the actual pin out and wiring diagrams. Research and documentation will show you how specific components need be setup. But regardless I’ve been through it all so I can answer most questions about the build, help with those gritty details when you hit them, and help if you hit a dead end and get stuck.

Before we start: A note to all

Before anything. I just want to mention how important planning is before starting any project. The most crucial part of this whole project is power distribution. Almost every powered device on the drone needs to be plugged directly into the battery. When attempting to get every on board device connected to a common power source issues are bound to show up. Please plan out your power connections meticulously and carefully!

Also* this thing is not a toy and can be dangerous in the wrong circumstances (calibrating motors with your face right next to the thing, test flights in public places, etc) Be careful! Please be careful to not hurt yourself or anyone around you!! Be respectful!

Good luck everyone! I hope your first drone brings you as much joy and excitement that mine has brought for me! and hopefully not as much blood!

Parts List:

  • 1X QAV250 Frame Kit: $30.98
  • 1X CC3D Flight Controller: $15.00
  • 1X 2.4Ghz RF Remote Controller: $58.99
  • 1X 5.8Ghz RF Video Transmitter: $21.99
  • 1X 5.8Ghz RF Video Receiver: $19.83
  • 4X Emax MT1806-2280KV Motors: $52.98/set of 4
  • 4X BLHeli 15A Speed Controllers. $30.00/set of 4
  • 1X RCA Video Display:$14.39
  • Multicopter propeller set (5″-6″): $10.00
  • FPV Video Camera: $17.99
  • 1X LiPo 11.1V 1500mah 3s Battery (for copter): $19.99
  • 1X LiPo 11.1V 2200mah 3s Battery(for video display): $12.25
  • 1X LiPo Battery low voltage protection circuit: $8.99
  • 1X MinopOSD Telemetry Display System: $15.59
  • 41X 12V RGB LED light strip set: $13.00
  • 1X FTDI Programming device: $15.95
  • 1X Propeller Guard Set: $12.00
  • 1X Power Distribution Board: $11.98
  • 1X T-Plug for battery connection: $5.00
  • 1X Motor Guard Set: $10.95
  • 1X LiPo 3s Battery Charger: $10.99
  • 1X Action Camera for HQ Recording: $45.00

Approximate total cost of this project: $450.42

Do note that this drone is fully loaded and you could definitely complete the project for cheaper if you slimmed down the parts list. This list includes FPV relays, a controller, all the parts for a FPV display, LED’s, motor guards, etc.

Complete Power Distribution Wiring Diagram

^ Fritzing software available online from “http://fritzing.org/home/” is required to view ^

Supplies / Tools:

  • Electrical Tape.
  • Solder / fine tip soldering iron.
  • A Perfectly Level Surface for calibration.
  • Pliers.
  • Wire Strippers.
  • Allen keys / small hex head screwdriver.
  • Philips head screwdriver.
  • Zip Ties.
  • 4mm Socket.

Software:

Requirements:

  • Basic Soldering Skills.
  • Basic Understanding of Electricity.
  • Patience.
  • Tinkering Time.
  • Obsessively Organized Wire Routing / optomization.
  • Determination (watch some competition drone FPV videos when discouraged).

Documentation:

Lets Begin!

Step 1: Assemble the Frame.

Assembling the frame should be one of the easier parts of the build. It goes together simply, and any variations in the configuration will not likely cause any issues, so go nuts! I’ve seen a few different configurations which work well, so setup the frame however it makes the most sense to you. (Or follow the instructions / obvious path if you just want to get it together).

Step 2: Mount motors & speed controllers.

Mounting the motors and speed controllers is one of the first things to be done after assembling the  frame. We can not solder the connections between the motors and speed controllers yet however, because we need to be able to test which direction they spin before solidifying the connections (this does not apply for speed controllers with programmable directions).

  • Mount Motors: in this process you will be sandwiching any motor / prop guards you might have picked out in between the motors and arms.
  • NOTE: Motors should spin in the direction which would tighten the prop nut if the prop nut is held stationary while the motor was spinning.
  • After managing to get the motors mounted, the speed controllers can be affixed to each arm easily with a bit of tape, zipte, etc. Just don’t cover up any of the connections between ESC and motor for future directional troubleshooting unless esc’s have programmable direction.
  • Although you will need to access the speed controller connections again, you also do not want any of the 3 connections touching one another, so a spot of tape is highly suggested to protect your hardware.
  • Be sure to mount the clockwise / counter clockwise motors in the right places: CC3S’s are setup like the following:
    Motor#1: Front Left: Clockwise.
    Motor#2: Front Right: Counter Clockwise.
    Motor#3: Rear Right: Clockwise.
    Motor#4: Rear Left: Counter Clockwise.

Step 3: Mount FPV Assembly.

In this step it is a good idea to setup and test any on board video equipment your drone might be carrying. This helps in organizing the connections for power distribution. I have my On Screen Display (MinimOSD) and video transmitter which both require power from my FPV setup, so getting those setup in a place where they can easily reach power is crucial.

  • Mount Camera.
  • Program OSD: In order to choose what is displayed on screen as telemetry data, you will need to plug your OSD into a computer with a “Basic FTDI Programmer” card.
  • Software Required to program the OSD.
  • Documentation regarding the OSD.
  • Mount OSD: this includes wiring the cameras video out to the OSD’s Video In.
    Wiring the Video Out from the OSD to the Video In of the Video Transmitter.
  • Note the video relay setup in my wiring diagram.

Step 4:Mount all Accessories which need to be powered.

Before continuing with power distribution it is highly suggested that you have your powered devices situated well, moving things after power distribution can cause havoc to your connections.

Step 5: Power Distribution.

After mounting all of your powered devices, routing and distributing power will be your next biggest challenge. Always solder your connections!

  • Route all of your power cables to your power distribution board.
  • Mount the power distribution board to the frame. (I use nylon PC motherboard standoff hardware to configure my board PDB/FC stack).
  • Solder in your ESC Connections.
  • Solder in any external connections (LED’s, FPV setup, etc).
  • Be sure to make low profile solder spots on the power distribution board. The CC3d and solder spots CAN NOT touch one another!

Step 6:Mount Flight Controller.

When mounting the flight controller there are a few specific points which need to be addressed for proper flight:

  • All flight controllers have a forward direction, usually dictated by an arrow painted on the board. It is crucial that the flight controller points forward when mounted on your aircraft.
  • Your flight controller is meant to stabilize your aircraft based on accelerometer and gyroscopic data. If the controller is not mounted flush to the aircraft’s frame control issues will arise.
  • In each plug connecting each speed controller to the flight controller, there are 3 wires. The red of these three supplies power to the flight controller. The issue is that you should only be powering your flight controller from an ESC if you do not have another power source. In this tutorial we are using a OSD device which supplies power through the 5V in on the flexi port to the flight controller. Because of this it is suggested that you disconnect all of the red wires connecting the ESC’s and flight controller if you are using an osd setup with 5V BEC.
  • If however: you need an esc for clean 5v power, use only a single esc, not all of them.
  • Be sure to note positive and negative on the CC3d pins and speed controller plugs, plugging backwards will fry your hardware!
  • Be sure to leave the USB port of your flight controller easily accessible.
  • Plug all plugs into flight controller (Remote controller, OSD telemetry, gps, etc).

Step 8: LibrePilot GCS Flight Controller Setup.

The main software used for setting up flight controllers is librePilot’s Ground Control Station or GCS. Using this software we can setup the flight controller configuration for flight. When entering the software for the first time, it is suggested that you go through the “Vehicle Setup Wizard” to get your aircraft and controller situated as quickly as possible. Using the software we will:

  • Zero accelerometer and gyro bias.
  • Set input channels and setup controller.
  • Set stabilization settings.
  • Set up flight modes so different tuning settings can be selected with the controller.
  • Adjust and test different PID tunings (Advanced stabilization settings).
  • Power up motors and check motor rotation for correct spin. If the motors don’t rotate the right way, swap any 2 of the connections between the motor and speed controller to switch the direction. For most QAV250’s the setup is:
    Motor#1: Front Left: Clockwise.
    Motor#2: Front Right: Counter Clockwise.
    Motor#3: Rear Right: Clockwise.
    Motor#4: Rear Left: Counter Clockwise.

Step 9: Tuning Speed Controllers.

After you have your connections good between the speed controllers and motors, we can talk about tuning the speed controllers. If you are having issues like the craft vibrates too much on liftoff, or the props won’t spin up, you might want to tune your speed controllers until you find a setup which suits your hardware configuration ALTHOUGH THEY USUALLY CAN BE CHANGED VIA SOFTWARE THROUGH STABILIZATION SETTINGS.

  • Speed controllers are individually programmable through the controller throttle.
  • The speed controllers have a number of options which are changeable by raising and lowering the throttle in correspondence with tones emitted from the speed controller.
  • Speed controllers need to be programmed individually. This is done by having only a single speed controller plugged into the flight controller and entering programming mode.
  • To enter speed controller programming mode: Hold the controller throttle at full while introducing power to your aircraft, with no disarming settings in place.
  • If programming mode is entered, the ESC will beep tones for each setting available on the controller.
  • When you pull the throttle down, you selected the setting which corresponds with the last beep.
  • At that point the controller will emit tones for all of the available options for that setting. Options are chosen by raising the throttle back to full.
  • You can exit the menu by pulling the throttle to the bottom directly after changing a setting or right after the last setting has passed.

 Step 10: Learning to fly

These things have touchy controls, both on the drone and controller. There are enough settings to make it fly however you want it to, but it still needs your calibration to make it comfortable to you. Be sure to take it easy at first. It may start out seeming impossible to fly, but you would be amazed how quickly you can pick it up. So whats the lesson here? Don’t wreck your aircraft before getting good at flying it. Here’s a few suggestions to hopefully help you get off the ground:

  • Always use arming settings so that the aircraft powers up disarmed. This will make changing settings in librePilot much faster since they prefer you to disarm it before changing settings. Arming settings will also help to keep your copter from flying away uncontrollably if the controller settings are out of whack.
  • Start out not using the FPV to fly, most people will tell you to only use the FPV, but thats only after you have the controls down. Get good flying line of sight before trusting the FPV completely.
  • NEVER DROP THE THROTTLE QUICKLY. You would be surprised by how much brush you can clear with the propellers without the copter being taken down. On the other hand, if you drop the throttle once you touch some leaves you are definitely going down.
  • Get good at landing softly, its difficult, but definitely a good skill to learn to keep your quad copter intact!

If you have any questions which you feel I have left unanswered, leave a comment. As I respond to peoples questions and concerns I will incorporate the info into the tutorial to hopefully create a more robust resource for future creators.

Thanks for reading!

Cheers!
-T

 

 

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s