In the next window, the software will try to identify the
hardware you have connected. If you are playing along with
the same hardware I am using, it will indicate “USB:
Revolution” as the connection device and “OpenPilot
Revolution” as the detected board type (Figure 2). Just click
The next window wants to know how the transmitter is
connected to the flight controller. We used the pulse width
modulated (PWM) configuration. Just select that and click
Next. The other modes have unique advantages and
disadvantages, but that’s another topic for another time.
On the next screen, select the appropriate vehicle type
(multi-rotor) and click Next.
The multi-rotor configuration screen is a lot of fun to
browse because it shows you just how many configurations
this piece of software knows how to fly. It’s a very
comprehensive list that includes configurations I didn’t ever
dream anyone would support. Our copter is of the
“Quadcopter X” style. Though our frame is shaped like an
“H,” the motor layout and forward direction match that
shown in the figure of the “X” design (Figure 3).
The next screen asks about the electronic speed
controllers (ESCs). Different ESCs will have different update
strategies. The AfroSlim models we are using are
particularly interesting because there is an entire community
centered around hacking the firmware on them to improve
performance and control type. If you were observant when
you took them out of the package, you will have noticed
that they even include the name of the hex file that is
flashed on the controller on the package. That’s something
you don’t see every day! I wasn’t exactly sure of the correct
mode here, so I followed the recommendation to leave the
default setting of “Rapid ESC” selected. Turns out that was
a good suggestion.
Some users choose to make their multi-rotor GPS
enabled so it can fly to waypoints, station keep, etc. I do
plan to do that, but I think that first it is important to get
the quad in the air and make sure we all know how to fly
without something helping us fight the wind and spoiling
us. For now, just leave the GPS setting disabled. The screen
following this will summarize our settings; just click past it
as we don’t need a connection diagram — we are all set.
The next part of the setup wizard will configure the
sensor zero points and ESC start points. The sensor zeroing
comes first. Here, the software will determine the offsets
and bias for your individual accelerometer and gyro sensors.
It is important that you place the vehicle on a sturdy, flat,
and level surface. I used a table, but made sure it was
actually level first with a carpenter’s level. It may be time to
pull out scraps of cardboard and paper to level things.
When you’re ready, click the “Calculate” button. After a
few seconds, the process will complete and the sensors are
Now, it’s time to set up the ESCs. You did remove the
propellers, right? It’s hard to tell which direction the motors
Figure 1: Upgrading the firmware on the flight
controller is a simple and essential process to
get the software and controller to work
together. It takes a few minutes to complete.
Be sure you are powering the flight controller
through the USB connection only.
Figure 2: If the
flight controller, it
should read “USB:
Figure 3: Even though our
airframe is shaped more
like an “H,” the relative
position of the motors and
the forward direction match
that of the “Quadcopter X”
setting. The difference in
geometry of our motor
supports doesn’t matter.
SERVO 11.2016 45