Hoverfly HoverflySPORT User manual

HoverflySPORT™
User’s Guide

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The information contained in this publication regarding device applications and use is intended by way of suggestion only and may be superseded by updates or
revisions. No representation or warranty is given and no liability is assumed by Hoverfly Technologies, Inc. with respect to the accuracy or use of such
information, or infringement of patents arising from such use or their compliance to any industry standards. Use of Hoverfly Technologies, Inc. products as critical
components in any life-saving systems is not authorized except with express written approval. No licenses are conveyed, implicitly or otherwise, under intellectual
property rights.
Copyright © Hoverfly Technologies, Inc. 2011. All rights reserved. Except as permitted under the Copyright Act of 1976 US Code § 102 101-122, no part of this
publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of
Hoverfly Technologies, Inc.
This document is distributed by Hoverfly Technologies, Inc. electronically and may not be printed and distributed without written permission.
Cover Art and Illustrations Alfred D. Ducharme except where noted.
Written by Alfred D. Ducharme with editing provided by George Sapp.
June 2011 Rev 1.1

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Thank You for Purchasing the HoverflySPORT™!
We started this company with one goal in mind…to make things that hover and fly! All of us have enjoyed the thrill of RC for many years.
We have poured our heart and souls into our hobbies and flown, drove, and sailed just about everything. In the last few years, the feasibility
of making Inertial Motion Units (IMUs) at a price that the average hobbyist could afford has become a reality. Many high-volume consumer
applications utilizing gyroscope, accelerometer, pressure, magnetometer, and GPS have shrunk both the size and cost of these sophisticated
devices. The affordability of IMUs has enabled an explosion of activity in the building and flying of multi-rotor aircraft. Part of this is the
inherent need for hobbyist to build something new to fly or control. The rest of the enthusiasm lies in the amazing flight capabilities of
hovering multi-rotor aircraft. They enable the pilot to navigate the airspace in ways only imaginable a few years ago. Add a camera, and the
user can gain amazing views of the world around us.
There has been a great deal of attention on the prototyping and productization of IMU’s in the last year. Yet many attempts fail because
without in-depth knowledge on how these devices operate and how to fuse the data into stabile flight outputs is extremely difficult. The staff
at Hoverfly Technologies all have advanced degrees in engineering and never shy away from challenging problems. The stable control of a 6
Degree-of-Freedom (6DOF) aircraft is one of the most complex problems to solve. We believe we have a great solution and the magic is in
our HoverCore™ technology inside every HoverflySPORT™.
We hope that you enjoy using the HoverflySPORT™ for many years. This product is the base for a line of add-ons to take your flying to the
next level. Please understand that software is never finished. We will periodically release new versions of firmware which can easily be
loaded onto the HoverflySPORT™ board. Make sure you check our site for updates to this User’s Guide and our firmware.
The Hoverfly Team!

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HoverflySPORT™

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A Note on Safety
The operation of any flying machine whether remote controlled or not can be dangerous. It is very important that you observe all necessary
safety precautions before (and after) flying. A safety check list is provided at the end of this guide for your reference; please make sure you
use it. Furthermore, this user guide is not necessarily fully inclusive of all information you may need to get your aircraft flying – this depends
on how you have built your aircraft – therefore please bear in mind that the information herein is intended as a guide and does not in any way
guarantee or undertake to guarantee your success. Lastly, since this guide has been compiled overtime time from numerous builds, it may
contain inaccuracies; do not rely on it solely.
All ways maintain control of your aircraft! One moment of showing-off can lead to a lifetime of regret.
There are old pilots and bold pilots but there are few old bold pilots.

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Table of Contents
1!About!this!guide!.............................................................................................................................................................................................................!10!
1.1!Content!Division!....................................................................................................................................................................................................................!10!
1.2!When!to!use!the!guide!..........................................................................................................................................................................................................!11!
1.3!Format!...................................................................................................................................................................................................................................!11!
1.4!Revisions!...............................................................................................................................................................................................................................!11!
2!Introduction!to!the!HoverflySPORT™!..............................................................................................................................................................................!12!
2.1!Multi"Rotor!Aircraft!..............................................................................................................................................................................................................!12!
2.2!Purpose!.................................................................................................................................................................................................................................!13!
2.3!Function!of!the!HoverflySPORT™!..........................................................................................................................................................................................!14!
2.4!HoverCore™!...........................................................................................................................................................................................................................!20!
3!What’s!included!.............................................................................................................................................................................................................!21!
3.1!In!the!box!..............................................................................................................................................................................................................................!21!
3.2!Also!included!.........................................................................................................................................................................................................................!22!
4!Installation!and!Building!.................................................................................................................................................................................................!23!

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4.1!Vibration!................................................................................................................................................................................................................................!23!
4.2!Configurations!.......................................................................................................................................................................................................................!24!
4.3!Transmitter!............................................................................................................................................................................................................................!25!
4.3.1!Channel!Requirement!.......................................................................................................................................................................................................!25!
4.4!Receiver!.................................................................................................................................................................................................................................!27!
4.5!Motor!Wiring!Harness!...........................................................................................................................................................................................................!28!
4.5.1!Proper!Soldering!(read!even!if!you!know!how!to!solder)!.................................................................................................................................................!28!
4.5.2!Current!vs.!Wire!Gauge!.....................................................................................................................................................................................................!29!
4.5.3!Battery!Source!...................................................................................................................................................................................................................!30!
4.5.4!Electronic!Speed!Controllers!(ESCs)!..................................................................................................................................................................................!31!
4.5.5!Connectors!........................................................................................................................................................................................................................!35!
4.5.6!Wiring!Harness!Layout!......................................................................................................................................................................................................!36!
4.5.7!Power!Filtering!..................................................................................................................................................................................................................!38!
4.6!Airframe!................................................................................................................................................................................................................................!38!
4.6.1!Airframe!Vibration!Dampening!.........................................................................................................................................................................................!38!
4.6.2!Stand"offs!..........................................................................................................................................................................................................................!39!
4.7!Brushless!Motors!...................................................................................................................................................................................................................!39!
4.8!Propellers!...............................................................................................................................................................................................................................!40!
4.9!Canopy!...................................................................................................................................................................................................................................!41!
4.10!Connecting!the!HoverflySPORT™!...........................................................................................................................................................................................!41!
4.10.1!HoverflySPORT!Orientation!...........................................................................................................................................................................................!42!

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4.10.2!Receiver!Connection!to!HoverflySPORT!™!....................................................................................................................................................................!43!
4.10.3!Configurations!"!!“+”!and!“X”!........................................................................................................................................................................................!44!
4.10.4!Configurations!–!Hex!and!Y6!.........................................................................................................................................................................................!45!
4.10.5!Configurations!–!Octo!and!X8!.......................................................................................................................................................................................!46!
5!Operation!......................................................................................................................................................................................................................!47!
5.1!Before!Flight!..........................................................................................................................................................................................................................!47!
5.2!Setting!Gains!.........................................................................................................................................................................................................................!48!
5.3!Arming!the!HoverflySPORT™!.................................................................................................................................................................................................!49!
5.4!Bench!Testing!........................................................................................................................................................................................................................!52!
5.5!Flight!Controls!.......................................................................................................................................................................................................................!53!
5.6!Basic!Flight!Mode!..................................................................................................................................................................................................................!54!
5.7!Advanced!Flight!Mode!..........................................................................................................................................................................................................!54!
5.7.1!Altitude!Hold!Function!......................................................................................................................................................................................................!54!
6!Update!Client!and!Setup!Utility!......................................................................................................................................................................................!56!
6.1!Firmware!Updates!.................................................................................................................................................................................................................!57!
6.1.1!Update!Procedure!.............................................................................................................................................................................................................!57!
6.2!Setup!Utility!...........................................................................................................................................................................................................................!61!
6.2.1!General!Tab!.......................................................................................................................................................................................................................!61!
6.2.2!Parameters!Tab!.................................................................................................................................................................................................................!63!

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6.2.3!Diagnostics!Tab!.................................................................................................................................................................................................................!63!
Appendix!A!–!Physical!Dimensions!..........................................................................................................................................................................................!64!
Appendix!B!"!Technical!Specifications!.....................................................................................................................................................................................!65!
Appendix!C!"!Quick!Start!Guide!...............................................................................................................................................................................................!66!
Appendix!D!"!Connection!Reference!.......................................................................................................................................................................................!67!

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1 About this guide
Ideally this User’s Guide represents the complete documentation for the HoverflySPORT™. We will make corrections and revision changes
as needed and certainly when new features are added.
1.1 Content Division
This document is divided into the following chapters:
!Chapter 2, “Introduction to the HoverflySPORT™” a description of the hardware.
!Chapter 3, “What’s Included” a brief list of the items included with your product.
!Chapter 4, “Installation and Building” provides information on configurations, wiring, and mounting.
!Chapter 5, “Operation” explains the different flight modes and set-ups required.
!Chapter 6, “Update Client” describes the operation and use of the firmware Update Client.
Quick Start Guide: If you already have a multi-rotor aircraft built and just want to
Plug-N-Fly™ you can jump directly to Appendix C – Quick Start Guide.

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1.2 When to use the guide
This guide is intended for builders and users of the HoverflySPORT™. It should be used when first installing the unit, before first flying your
aircraft, and throughout the use of the product. The guide assumes that the user has some knowledge of power and servo connections,
basic electronics, and updating the firmware of electronic devices.
1.3 Format
The manual was formatted in Landscape mode to make it easier for the user to read on a typical widescreen display. This decision was
made because it is distributed electronically rather than in printed hardcopy form.
1.4 Revisions
This guide should be considered a “living” document. There will almost certainly be errors both in form and function. Understand that new
revision will be released periodically and you should check periodically for updates.

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2 Introduction to the HoverflySPORT™
This chapter is both an introduction the HoverflySPORT™ and multi-rotor aircraft in general. It is meant to be resource for anyone just
entering the hobby of building and flying multi-rotor aircraft. Even though many of the concepts presented here are known by experienced
users, we hope that it useful for all experience levels.
2.1 Multi-Rotor Aircraft
A multi-rotor aircraft is a remote controlled vehicle that utilizes more than one motor to provide lift and control flight. Just as a table must
have three legs, at a minimum a multi-rotor aircraft must have three motors. It is possible to have fly a vehicle through the air using only two
motors but that is not the intent of the HoverflySPORT™. We consider a multi-rotor vehicle to contain at least three motors. However, this
would require that one or more of the motors could turn on an axis perpendicular to the center of the airframe. Therefore, the minimum
number of motors that must be used with the HoverflySPORT™ is four (4). In addition, the orientation of these motors needs to be at equal
angles. For a four motor aircraft the orientation of the motors would be all pointing in the same direction (usually up) and they would be
positioned at the end of two straight crossed members as shown below, Fig. 1.

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Figure 1. Basic Quadcopter or Quadrocopter motor configuration (frame by Droidworx)
2.2 Purpose
The HoverflySPORT™ in a very basic sense is the middle-man between your control inputs and the motor electronic speed controllers
(ESCs). Without it the aircraft would be nearly if not completely impossible to fly. The original stealth fighter, the Lockheed F-117 Nighthawk,
first flown in 1981 was a revolutionary aircraft for two reasons. First, the stealth technology provided nearly invisible flight through the most
sophisticated radar patrolled areas. Second, the best pilots couldn’t fly it safely. How could this be? The same invisibility stealth technology
yielded an aircraft with very unstable flight characteristics. So the second revolutionary aspect of the F-117 wasn’t that it couldn’t be flown

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but rather a Flight Computer was needed between the pilot and the control surfaces. The HoverflySPORT™ acts as the Flight Computer for
your own multi-rotor aircraft.
The primary function of the HoverflySPORT™ is to monitor the orientation of the aircraft and drive the multiple motors to achieve stable flight.
The user’s control inputs are then used to adjust the aircraft away from a stable orientation by pitching, rolling and yawing (spinning) the
platform. These actions cause the aircraft to move in different directions so that it can effectively be flown within an airspace. Sounds pretty
easy but to achieve this data from gyroscopes, accelerometers, and a pressure sensor are fused together thousands of times a second. This
information is then used to make decisions on how to achieve the pilot’s desired orientation.
The purpose of the HoverflySPORT™ is to make the job of piloting an inherently unstable multi-rotor aircraft easy. Easy is a relative term
here since some time on the sticks with other types of aircraft helps a great deal. However, we strive to make the HoverflySPORT™ the
most capable Flight Controller on the market and this means over time easy will be even easier. Ultimately, our goal is to make the flight of a
multi-rotor aircraft effortless to the point that anyone can pick up a transmitter and give it a try without crashing.
2.3 Function of the HoverflySPORT™
The HoverflySPORT™ is designed to control several different configurations of multi-rotor aircraft. A more detailed description of the
supported motor configurations is given in Chapter 4. For now it will be assumed that a basic four motor configuration, called a quadcopter,
will be used with the HoverflySPORT™.
The following diagram, Fig. 2, shows the basic connections that are needed for a quadcopter. As described in the previous Section 2.2, the
HoverflySPORT™ is the middle-man between the pilot and the motors of the aircraft. Therefore, the connections on the aircraft follow this
methodology. The Transmitter sends the pilots control inputs (the sticks) to the Receiver on-board the aircraft. The Receiver is then
connected to the HoverflySPORT™. The HoverflySPORT™ is then connected to the Brushless Electronic Speed Controllers (ESCs). The

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function of the ESCs is to take information from the HoverflySPORT™ and turn it into a 3-phase control signal. This 3-phase signal drives
the brushless motor to attain a rotational speed to a certain number of revolutions per minute (RPM).
Figure 2. Diagram showing the operation of the HoverflySPORT™ on a quadcopter
Ideally, under perfect windless conditions while the control inputs are centered the RPMs of all motors is equal. If a disturbance to the
environment occurs such as a gust of wind, the HoverflySPORT™ will change the RPMs each motor to continue to maintain the commanded
center stick orientation. Thereby, maintaining the position of the aircraft.

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In order to move the quadcopter forward the pilot would actuate the elevator (European customers may use left stick on mode 1 transmitters,
maybe find a different term) control input up on the transmitter. This will cause the HoverflySPORT™ to rotate the quadcopter forward called
Pitch. If the pilot continues to hold the stick in the forward position the quadcopter will continue to pitch forward and eventually turn
completely upside down. This is because in normal mode of flight (there are different modes discussed in Chapter 7) the control stick
position is equal to the rotational rate of the quadcopter. More control input (moving the stick up further) results in a higher rotational rate.
Less control input (moving the stick up slightly) results in a lower rotational rate.
Figure 3. Rotational rate is proportional to stick angle.

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Therefore, in order to move the quadcopter forward (without crashing it) the pilot must first initiate a slow rotational rate or pitch forward. The
control input must be centered to maintain the angle-of-attack of the quadcopter. To stop the forward motion the control input must reversed
by moving the stick downward slightly to right the quadcopter. Then the stick is centered when the quadcopter is level to the ground.
The right control stick can also be actuated right and left. This will cause the quadcopter to rotate right and left called Roll. Once again the
angle of the control stick is equal to rotation rate. Moving to the right would consist of first moving the stick right slightly, centering the stick to
continue motion, then moving the stick left to level the quadcopter.
So far we have covered Pitch and Roll of the quadcopter but there are two other motions. First, the left control stick is used to control the
altitude of the quadcopter by increasing and decreasing the speed of the motors (also referred to as throttle). This stick starts in the down
position and corresponds to zero throttle and the motors will not spin. As the stick is moved up, the RPMs of the motors will increase. Every
quadcopter has a sweet spot based on the weight of the aircraft and motor size where a constant altitude is maintained. This is called
hovering and occurs when the quadcopter stays a single height above the ground. To increase the altitude of the quadcopter, the left stick is
actuated upwards increasing the speed of the motors. This causes the quadcopter to rise and gain altitude. To hover at a new altitude the
stick is moved back to the sweet spot. It will take some time and practice to discover the sweet spot and find it quickly after changing altitude.
One of the challenges you will have is that the momentum of the quadcopter as it moves up and down requires some throttle counter action.
In other words, after you change altitude you will need to increase or decrease the throttle around the sweet spot to fix the altitude. This is
especially true when decreasing altitude. Once the quadcopter moves down to the desired altitude a swift increase in throttle will be required
to offset the momentum of the falling aircraft.

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Figure 4. Control stick movement and aircraft roll, pitch, yaw, and throttle (altitude).

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This leaves one more motion to cover called Yaw. Yaw is the spin of the quadcopter around the vertical axis. First, let’s take a look at how
the quadcopter counteracts Yaw. A traditional helicopter has a single rotor spinning in a constant direction. In addition, a helicopter has a tail
boom with a smaller vertical rotor. The pitch or speed of the tail rotor is used to counteract the rotational force of the main rotor. Without the
tail rotor (and many of us have unfortunately experienced this in a failure of the tail rotor) the helicopter will spin in the opposite direction of
the main rotor. The tail rotor maintains the forward direction of the helicopter. Turning the helicopter or inducing Yaw requires a change in
the tail rotor.
A quadcopter lacks the tail rotor of a traditional helicopter. So how is Yaw control achieved? Remember that the helicopter has a single rotor
spinning in a constant direction. In order to control Yaw, a quadcopter has to balance the rotational force of the four motors. This is achieved
very simply by spinning two motors in the clockwise (CW) direction and two motors in the counter-clockwise (CCW) direction. With all four
motors spinning at the same RPM, the rotational forces are balanced so that the quadcopter doesn’t spin. In order to command the
quadcopter to spin in the CW direction this balance is adjusted. The speed of the CW motors is increased while the speed of the CCW
motors is decreased. The overall thrust is maintained by this see-saw increase/decrease so that the quadcopter maintains altitude while
turning in the CW direction. To Yaw the quadcopter in the CCW direction the see-saw balance is reversed.
The transmitter sticks allow the pilot to control the Roll, Pitch, Yaw, and altitude of the quadcopter. All of the complexity of flying a naturally
unstable quadcopter is handled by the HoverflySPORT™. Even environmental disturbances such as wind are monitored to enable
consistent flight.
Flying a quadcopter with a HoverflySPORT™ is a bit different from other aircraft such as planes and helicopters. Take for example the case
where the quadcopter is flying into a gust of wind. The HoverflySPORT™ will compensate for the wind so that the same user inputs achieve
the same flight as in windless conditions. The pilot will then only need to adjust the throttle to maintain level flight similar to an airplane or

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helicopter. The difference with a plane is the reaction that the aircraft will have to the increased airspeed over the wings. The quadcopter will
feel the same going into wind whereas a plane will not.
Other flight modes such as Auto-Leveling change the flight characteristics of a multi-rotor aircraft and make it even easier to fly. These
modes will be covered in Chapter 7. However, the beginning pilot should start with the basic rotational rate input flight mode.
2.4 HoverCore™
The HoverflySPORT™ flight controller system is based on our core Sensor Data Fusion technology called HoverCore™. Lots of data from
accelerometers and gyroscopes is useless no matter how fast you sample if the data is not fused effectively to provide stable flight control
outputs. Our propriety HoverCore™ algorithm utilizes parallel processing architecture to independently collect senor data. Then the algorithm
utilizes custom digital filtering to extract only the necessary variables from all available data. The flight control algorithm utilizes the data it
needs to generate Pulse-Width-Modulated (PWM) signals to accurately control external ESCs. All of this happens hundreds of times a
second to provide reliable and highly stable flight control.