HFX900 Manual V0.80

HFX900 Manual V0.80
R/C System
HFX900 manual v0.8 Draft
Congratulations on your purchase of the HFX900
R/C System. These instructions cover the use of the
HFX900 transmitter, Micro900 (Micro9) series
receivers, and LP90 Bahoma cell and charger.
There are several types of 900Mhz receivers available for the HFX900 Transmitter. For this version of
the instructions manual, we have 2 types of
receivers, a 0.9 gram Micro900 (also known as
Micro9 receiver) receiver and a 0.38 gram Micro900
The 0.9 gram receiver is the heavier receiver model
and it is the easiest to set up. It has microconnectors for connecting motor, and 2 actuators, and
magnetic “Bahoma” battery terminals.
The lower weight models save weight by elimination
of these microconnector parts. To use the 0.38 gram
receiver soldering fine wires to small PCB pads is
required. If you have no experience in Micro R/C or
soldering, the Micro900 0.9 gram receiver - will
make it easy for you to build up an airplane without
any need to do small surface mount soldering.
The HFX900 transmitter has a few extra features
built-in - you can use your transmitter with the
included Freeware FMS flight simulator and learn to
fly on your PC ! Lithium Polymer airplane cells can
be charged and stored right on the transmitter with
Plantraco’s patent pending Bahoma magnetic battery connector. State-of-the-Art Pure Digital 900Mhz
RF link means solid radio control, no more long
antennas, and you’ll have plenty of radio range for
indoor and outdoor Micro R/C flying.
Battery discharging, charging, electric motors, spinning propellers,
and flying models all have the potential for serious injury to persons
and damage to property. In purchasing these products, the user
agrees to accept responsibility for all such risks, and not to hold the
manufacturer, distributors, or retailers responsible for any accident,
injury to persons, or damage to property.
• HFX900 (HFX868 in Europe) Proportional R/C
Transmitter/Charger “R/C Air Model 1” Centering Throttle or Non Centering Throttle
(900Mhz-USA, 868Mhz-Europe)
• Micro900 0.9 Gram Receiver
• Micro900 0.38 Gram Receiver
• FMS Flight Simulator Interface Cable and FMS Software CDROM
with Computer Models of the Plantraco MicroScout and (soon)
Butterfly (FMS is a freeware R/C Flight Simulator - bundled with
permission from the author - you can also download it and all the
Plantraco FMS flight sim model files from links at:
• LP90 - 90mAh Lithium Polymer Bahoma Cell
Web Page www.plantraco.com www.microflight.com Email ufoman@plantraco.com Orderline 306-955-1836 Fax 306-931-0055
Magnetic Battery Terminals
Add Batteries to Transmitter (See Fig. 2.5)
Remove the rectangular battery cover from the back of the Transmitter. Insert 4 “AA” Alkaline batteries taking note of proper polarity of
positive and negative contacts (Negative end of the battery should make
contact with the “spring”).
Plastic Safety Guard
Fig. 1. Bahoma Battery Connector
(patent pending)
Charge Lithium Polymer Rechargeable “Bahoma” Cell
The included lithium polymer cell features Plantraco’s Bahoma (BAttery HOlder using MAgnets) connector (patent pending). The Bahoma
connector system uses strong plated magnets to hold the battery onto
the charger and onto the Micro900 receiver. These magnets are also
used as electrical conductors. The terminals of the Bahoma cell are
protected from shorting to each other by a plastic safety guard.
(See Fig. 1)
Trimmer Wheels
On the front of the transmitter, slide the 3 position switch to the middle position to put the transmitter into it’s “Charge” mode. The LED
inside the charger door will be blinking rapidly. Slide the hinged
clear polycarbonate plastic charger door downwards to unlock it, and
then lift it open. Attach the Bahoma cell to the corresponding magnetic terminals. The Bahoma cell will “click” into place on the charger by
magnetic attraction and with good electrical contact. The LED inside
the charger will now glow brightly. Close the clear charger door, and
slide it up to shut it with a small click. Your cell is now charging,
and when the bright LED goes out, the cell is fully charged and ready
for use. Charge time is about 60 minutes typically. The charger is set
to charge at 78mA. (See Fig. 2)
3 Position
Magnetic Charger Terminals
Charger LED
Fig. 2 HFX900 Transmitter with Built-In Charger.
Important Notes about Lithium Polymer Batteries
The lithium polymer rechargeable battery should not be used if it has
become swollen or has been physically damaged, crumpled, or cut.
Always use the supplied charger built into the transmitter. Always
charge the LP90 cell with the clear charger door closed. The supplied
lithium polymer cell can provide you with many discharge cycles
when used properly, but eventually it will require replacement.
Replacement cells are available from your dealer or from Plantraco
directly at www.plantraco.com. Always dispose of used or damaged
batteries appropriately
If you need to dispose of a damaged Lithium Polymer cell, you can
make a solution of about 2 cups of water and 1 cup of table salt in a
disposable container outdoors. Put the damaged cell in this concentrated salt water solution and leave it outside overnight. The damaged
cell may then be disposed of in the garbage safely.
Fig. 2.5 Insert “AA” Batteries with Correct Polarity
Replacement cells are always available from your dealer or from the
plantraco website www.plantraco.com
Micro900 0.38 Gram Receiver
This older, but lower weight receiver version has outputs for 1 motor
and 2 magnet actuators. The software on this receiver uses PFM
instead of PWM for control of actuators. This should result in the
same power to the actuator, but is easier on small batteries, and has
the unusual side effect of making unusual robot sounds from the
This version of the instruction manual only covers the 0.38 gram and
0.9 gram 3 channel Micro900 Receivers. The 0.9 gram receiver is
intended to be easy to use, and the 0.38 gram model has been produced on thinner PCB material and without magnets and microconnectors - resulting in a good weight savings. Most of this manual
will apply to both of these receivers, but there are always a few exceptions. Lower weight receivers and other receiver variations are in the
Note that all Plantraco Micro900 receivers can sync to the HFX900
(American model) AND HFX868 (European) transmitters.
Micro900 0.9 Gram Receiver
This small circuit board receiver has microconnector outputs for 1
motor and 2 magnet actuators. 2 magnetic battery terminals (Bahoma
-spaced 10mm apart). 2 short wire on the top side of the receiver are
the dipole antenna. The receiver can report status to the user by use
of an LED indicator light, and also by making high frequency tones
emitted through the magnetic actuator itself You will find these audible tones useful - they can tell you if you have successfully started
your receiver, synced to your transmitter, and what frequency you
have synced to.
Fig. 4 Micro900 0.38 gram receiver.This one has no
Bahoma Magnets, or connectors.
Low Battery Protection - built in failsafe.
The Lithium Polymer Bahoma battery should not be discharged lower
than about 2.7 Volts. The low battery failsafe function of the Micro900
receiver will ensure that you do not over discharge your lithium polymer battery. It will warn you when your battery is low and needs to be
recharged by cutting the throttle to 60% when cell voltage is getting
low. You can continue to fly if you wish - the attenuated throttle usually allows the lithium cell voltage to rise, so maybe you can still fly
for a little bit longer. When the cell voltage drops even lower, the
throttle will then be cut to 30% and you will most certainly have to
land your model.
The receiver measures cell voltage while your are flying, and the LED
will blink a series of flashes to indicate the general state of the battery
voltage. You won’t notice this when you are flying, but this functionality is built in if you want to do some bench testing etc. If you leave
the battery on the receiver for too long (like overnight) you may over
discharge and damage the cell - so be sure to disconnect it and
recharge when you are done
Fig. 3 Micro900 0.9 gram receiver with Bahoma and
microconnectors - easy to configure!
Multi-Frequency Operation
This 900Mhz R/C System (868Mhz in EU), can be configured for use
on one of 3 radio frequencies “channels”. You select your channel
when you switch on your transmitter. The position of the Left joystick
at startup controls what channel you will use. When you startup the
Transmitter, you can hold the Left stick to the Left, leave it in the middle (default), or hold it to the Right, to configure operation on Channels 1, 2 and 3 respectively. Default is Channel 2 (left stick is in the
middle position). (The European frequencies are designated as numbers 4, 5 and 6 respectively, and are accessed in exactly the same
way) The American version of the HFX900 transmitter is capable of
transmitting on CH 1, 2 and 3 ONLY. The HFX868 transmitter is
capable of transmitting on CH 4, 5 and 6 ONLY. (See Fig.5 )
When selecting a Channel on startup, you can hold the Left joystick in
a position for about 2 seconds and let it spring back to center when
you are ready to transmit. Channel 2 is the default channel because
the Left joystick is a self centering joystick, so this channel is always
selected by default if you switch on the transmitter without holding
the Left joystick in any particular position. If you are flying alone, you
will probably be transmitting on channel 2 (CH 2) most of the time.
The receiver will look for the lowest channel number first and will
lock-on (sync) to the transmitter that is broadcasting on the lowest
channel number. It also will compare received signal strength, but for
practical purposes, the lowest channel number is the most important
factor for the receiver.
When you are flying in the same room as others, The first user to start
up his airplane should use channel 2 or 3, and the second user can
use channel 1. Therefore up to three people can fly in the same room
simultaneously. The first person should use CH 3, the second should
use CH2 and the third person should use CH1. All three channels can
be used together without risk of interference from the others. If the 3
people flying in the same room are aware of what channel they are
using, they will be able to allow a new flyer to join in, so long as the
new user can select a lower channel number than what is currently
being used. If you are flying with your friends, put the longest flying
airplane on CH 3, and then let the other airplanes use the lower channels.
For example, if the first user will want to have a long 20 minute flight,
he should use CH 3. Then if other users want to start up their planes
too, they can use CH 2, and the last guy gets to use CH 1.
If there is going to be a lot of people coming and going, or one user
is using CH 1 and wants to fly for a long time, the other flyers would
obviously not be able to select a channel lower than CH 1. They can
wait for the CH 1 airplane to finish his flight, or they can take their
model into a different room, or move about 100 feet away and try to
sync their receiver to CH 2 or CH 3 - in this way, they are using the
received signal strength to force the receiver to sync to CH 2 or CH 3,
even though a transmitter maybe be transmitting on CH 1
Future models of the HFX900 may have more channels (frequencies)
in the 900Mhz ISM band, or may use a frequency hopping technique.
This is not available on the first version of our HFX900 transmitters
and receivers, but we are working on it. For now the 3 channels will
allow most Micro R/C flyers to fly with friends interference free
(CH 4 Europe)
(CH 6 Europe)
Fig. 5 - Configure Transmitter functions by holding
stick positions while switching transmitter ON
Transmitter Mixing Modes
There are 4 user-selectable “Mixing Modes” available on the transmitter. (See Fig.5 ) You select your “mixing mode” when you switch
on your transmitter The mixing mode you choose will be saved in
memory until you make another selection - even if you switch it off.
The position of the Right joystick at startup controls what mixing
mode will be selected. The factory default mixing mode is “Normal”
rudder and elevator mixing, this can also be selected at startup by
holding the Right joystick to the right for about 2 seconds. When you
startup the Transmitter, you can hold the Right joystick to the left to
select “Negative Exponential” mixing that might be useful to dampen
your joystick controls for squirrely models. When you startup the
Transmitter, you can hold the Right joystick down to select “V-Tail”
mixing for elevon style planes “Flight Simulator” mixing mode is
accessed by pushing the Right stick up at startup - which will put the
transmitter in to a non transmitting state that is used only when we
want to connect the transmitter to a personal computer for using the
freeware FMS flight simulator software. Note that the selected mixing
function will remain in memory, even if the transmitter is switched
OFF - This can be convenient, but it can also cause confusion if you
forget what mixing mode you are in. So if you use the non-transmitting FMS function, you’ll have to remember to select another mixing
mode when you want to fly your real airplane - if you forget to do
this, it might seem like your transmitter is not working - you have to
remember what mixing mode you left your transmitter in.
Normal Mixing (Right Stick to Right)
This style of mixing is for 3 channel rudder and elevator. The Left
stick controls the motor throttle. The Right stick controls rudder and
Adjusting the Trimmers
Rotate the trimmer wheels with your thumb until you have successfully stopped any buzzing of the actuators. Most experienced R/C pilots
will have no problems with this, but if you are a beginner, it might
seem strange for now. Basically you will want the trimmer wheels to
be positioned near the middle of their full range of motion. Make sure
you know what mixing mode your transmitter is configured to. If you
are confused, remove the Bahoma cell from the receiver, and review
the transmitter mixing functions and start again
Negative Exponential Rate - (Right Stick to Left)
This makes the control response milder around the joystick center
point, but it becomes increasingly stronger as the input approaches
100%. This can help for taming squirrely models.
V-Tail Mixing - (Right Stick Down)
For models that combine elevator and aileron function on two control
surfaces, like flying wings and V-tail planes.
FMS Mode - Selected at startup (Right Stick Up)
The FMS mode shuts down the radio functions of the transmitter and
instead sends signals through the monophonic audio jack on the left
side of the transmitter box. A special cable connects the transmitter
to a personal computer with the freeware FMS software installed, and
you can use the HFX900 transmitter as an R/C Flight Sim input
Establishing Transmitter-Receiver R/C Link
Turn on your transmitter by pushing the 3 position switch all the way
to the far right. The main transmitter LED will glow. It is always best
to turn the transmitter on first.
The receiver should have 2 actuators and one motor connected.
The receiver can communicate to the user with audible tones and LED
blinking sequence.
Attach the LP90 cell to the receiver, you will notice a distinctive audible musical arpeggio tone sequence (musical notes C-E-G-C-G-E-C)
that indicates successful microprocessor startup. This arpeggio is followed by a two-tone repetitive sequence (C-E,,,C-E,,,C-E -- and so
on). This repeating two-tone sequence indicates that the receiver is
scanning for a transmitter signal - it will continue to repeat until a
valid transmitter signal is received. Once a valid transmitter has been
found, the Channel number will be indicated by a series of tones (G
note). The default transmitter channel is Channel 2, so you should
hear two “G” notes to indicate that the receiver is operating on Channel 2. (European HFX868 default is CH 5, so in Europe, you get to
hear 5 “G” notes indicating the receiver is operating on Channel 5.
Once you hear the final count of “G” notes, you will know that your
HFX900 system is ready for action. The actuators may start moving
and buzzing, and if your throttle stick or throttle trim is not adjusted
the propeller may be spinning, so be mindful of this. You will be able
to control the actuators by using the Transmitter Joysticks, (See
Fig.6 )but first you will need to adjust the trim by moving the small
trimmer wheels located near the transmitter joysticks
Fig 6 . Basic R/C Aircraft Control
HFX900 (Americas) Frequencies
HFX868 (Europe)Frequencies.
868.105 Mhz
868.385 Mhz
869.910 Mhz
Using the HFX900 Transmitter for the FMS
You can see the blue bars moving up and down to confirm full range of
Two or three big circles with both sticks should be fine.
Click Ok.
And then click ok again.
R/C Flight Simulator
To use our transmitter in the FMS joystick mode, connect the supplied
serial cable to your Windows PC and insert the mono plug into the jack
on the left side of the transmitter.
The aircraft on screen should now start rolling ahead - You should now
be able to affect the aircraft by moving the control sticks.
We have included a CDROM that has the FMS Flight simulator, and
also has the Plantraco MicroScout FMS model. Soon we will be
adding the Butterfly FMS model and other items to the CDROM.
To switch back to a transmitting mode hold the right stick to the right
and simultaneously switching the transmitter from off to ON.
If you lose the CDROM that was included with your system, you can
download the freeware Flight Simulator "FMS"
The Windows Installer can be downloaded here:
The official website for FMS can be found here:
Once downloaded launch the installer and choose your installation
directory (Normally "C:\Program Files\" ) This should already be the
default, and you can just press next.
You can choose to put an Icon on the desktop for easy launch of the
application. The program should be installed.
You can Launch the program from the icon located on the desktop or
from the start menu.
With the Serial Cable attached to the computer, and the mono plug
inserted into the jack on the side of the transmitter, hold the Right stick
Up - while simultaneously switching the transmitter from off to ON
The transmitter will now be in the NON TRANSMITTING mode and can
be used as an input device for the flight simulator.
In the FMS program click the menu "Controls" then click on " Analog
controls…" .
Select "Serial PIC Interface" and then click the button marked
"Resources". Then you will need to select the com port which the cable
is connected to. (Probably COM1)
For the Baud Rate Choose "19200" . Then Press OK
Then Click "Mapping/Calibration" then click "Calibrate" you should
now move both sticks in all directions to allow the software to adjust to
the range of motion available.
tact. If the magnets are well apposed to each other, they should
stick fine and you won’t shake them loose anymore
• You can also try using a small piece of tape to securely affix the
battery to the receiver if your airplane is a bit shaky in the air. If
your gearbox and prop are well balanced, you will have less shaking of your model in the air - you can check that too to reduce
We hope that you won’t have any problems with your HFX900 system,
but if you do, check this Troubleshooting list first.
1. My Receiver played the startup tones through my actuator at startup, but then it just plays the C-E tones over
and over - it keeps beeping.
• Check transmitter - Make sure the switch is all the way to the right
and the transmitter LED is glowing
• Is the transmitter in FMS mode? Switch the Tx off for a few seconds and then startup with the Right joystick held to the right for 2
seconds - Let the stick go and you should be in normal rudder
elevator R/C mode again. Now remove the battery from the receiver and start it up again. You should hear the arpeggio tones, and
then the C-E tones and then a few G tones to tell you what channel
you have just locked-on (synced) to.
• Change your Transmitter batteries for fresh ones and try again
• Check if your receiver still has it’s antennas - have they been broken off or cut? replace and try again or contact Plantraco
5. I crashed my plane, and now when I start up the receiver, I don’t hear any tones at all and I can’t seem to sync
• Check your magnetic actuator wiring - broken wire?
• Check the LED on the receiver - does it blink when the receiver is
powered up with the cell? It should
• Does the LED blink in an S-O-S pattern for about 10 seconds and
then it does play some tones? If it does, this means your cell needs
to be recharged
• Check magnets on your cell and on the receiver - are they all still
attached and intact? If they have broken off of the cell, you’ll need to
replace or repair it - If a magnet has broken off of the receiver, contact Plantraco
• Check the magnet terminals to see if there is any magnetic debris
coating the cells, preventing a good electrical connection. If there is,
clean them off with a Q-tip, toothpick, small flathead screwdriver etc
Dip your Q-tip in rubbing alcohol, this can clean the crud off your
magnet terminals
• Check the bahoma cell - measure volts with voltmeter. You should
be above 4 Volts for a fully charged cell
• Perhaps in the crash, you broke a solder joint on the PCB - if you
know how to solder, you can try to reheat the solder joints of all
components until you fix the problem, or you can contact Plantraco
for more advice or repair services.
2. When I charge my LP90 cell on the built-in charger of
the transmitter, the LED goes out right away, but the cell
doesn’t seem to have much power anymore.- Or - It
seems to be taking forever to charge my LP90 cell.
• Replace the AA batteries in the transmitter- they are probably low and
we have to have greater than 4.4 Volts left in the 4 AA cells in
order to charge up the LP90 cell. A normal Charge will take about
60 minutes With fresh AA cells in the transmitter, you should be able
to get about 10 charges of your LP90 cell - you may get more, depending on how you use your cells, but eventually, the AA cells of the transmitter will become depleted, so be mindful of the charger LED. It can
be a good idea to use a digital volt meter (these are often available for
less than $15.00 these days) to check your cell voltage once in a while.
6. I can’t get FMS to work properly
• Make sure you put your transmitter in FMS mode. Do this by holding the Right Stick in the up position at startup of the transmitter.
You can check that the transmitter is in FMS mode by starting up
your receiver - it should keep beeping without syncing to the
transmitter since the transmitter should be in the non-transmitting
FMS mode now. If your receiver can still sync to your transmitter,
you are not in FMS mode.
• Follow the directions on the CDROM carefully. Re-install FMS, or
call your local computer guru to help you. It’s easy, but maybe
your system is messed up. We’ll have more tips on FMS mode on
our website, just go to
3. I sync up fine, but the controls seem to be reversed or
something - when I give it elevator, I get rudder - it’s all
messed up
• You are in V-Tail mixing mode. Power off the transmitter for 5
seconds and restart the transmitter while holding the Right joystick
to the right for about 2 seconds and when you release it, you
should have normal control again.
4. I sync up fine, when the models is throttled up or is
shaken, the battery seems to lose it’s connection, and
the receiver starts up again, I can hear the tones.
• Try squeezing the Bahoma battery magnet terminals of the cell and
slide the battery around on the receivers magnets when you make
a connection - this will help to clear any debris that might be preventing the Bahoma magnets from getting a good electrical con-
Ready To Fly Models from Plantraco
Coming Soon!
4 Gram R/C Butterfly
Special Thanks
We are very grateful for the advice and support we received
from experts in the hobby community. Especially the people
below who graciously offered their expertise to us, spent lots
of time talking and corresponding with us - all for the love
and advancement of this wonderful hobby!
Each of you has contributed to this project in one way or
another, and by giving us your good advice over the last year.
So we are indebted to you.
To Re-Order Spare Parts etc. Call your
Local Dealer or Plantraco Direct at:
World Wide Web at:
Email us at:service@plantraco.com
Ramon Crichlow
Peter Hudson
Gordon Johnson
Fritz Mueller
Jean-Daniel Nicoud
Henry Pasquet
John Piri
Petr Saroch
Bob Selman
Jason Toews
Brian Wolfe
John Worth
Any changes or modifications (including the antennas) made
to this device that are not expressly approved by the manufacturer may void the user’s authority to operate the equipment.
HFX900 Manual v 0.8 Copyright 2005 All Rights Reserved
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