Using a Simulator for tests

As the transmitter can now generates a PPM signal, I can use it as a "ppm Joystick" to any sofware simulator that take USB-PPM cable as input. For instance crrcsim or Phoenix, which are 2 really good sims, the first one for glider, and Phoenix for helico/planes. For crrcsim, the USB-Futaba connector cable works well, and for Phoenix there is a specific USB cable for Futaba. One both cables, it just need to connect the ground and the PPM signal. Using a simulator program like that, it a very good test for the coder, as there is no intermediate which may fail and demonstrates pretty well response times, and test any kind of input combination.

configuration file example

Configuration file for aerobatic glider with flap,snap and butterfly:

mcontrolmgr mcontrol=0 adc=0 calib_max=941 calib_min=76 calib_zero=504
mcontrolmgr mcontrol=1 adc=1 calib_max=898 calib_min=113 calib_zero=508
mcontrolmgr mcontrol=2 adc=2 calib_max=938 calib_min=76 calib_zero=475
mcontrolmgr mcontrol=3 adc=3 calib_max=979 calib_min=42 calib_zero=418
mcontrolmgr mswitch=5 pin=5 port=C
mcontrolmgr mswitch=6 pin=6 port=C
chanoutmgr chanout=0 cname=aileronG
chanoutmgr chanout=0 smix=0 straight sw=15 rev=0 rate=93 name=aileron inh=0 in1=0 offset=0
chanoutmgr chanout=0 smix=1 straight sw=6 rev=1 rate=23 name=snap inh=0 in1=2 offset=0
chanoutmgr chanout=0 smix=2 straight sw=15 rev=0 rate=-51 name=bfly inh=0 in1=1 offset=-198
chanoutmgr chanout=0 smix=9 fixcte sw=5 rev=1 name=flap inh=0 offset=162
chanoutmgr chanout=0 trans=3 reverse rev=1
chanoutmgr chanout=0 trans=4 chantrim offset=90
chanoutmgr chanout=0 trans=5 chanbounds max=1024
chanoutmgr chanout=1 cname=voletG
chanoutmgr chanout=1 smix=0 straight sw=15 rev=0 rate=40 name=aileron inh=0 in1=0 offset=0
chanoutmgr chanout=1 smix=1 straight sw=6 rev=1 rate=40 name=snap inh=0 in1=2 offset=0
chanoutmgr chanout=1 smix=2 straight sw=15 rev=0 rate=56 name=bfly inh=0 in1=1 offset=1024
chanoutmgr chanout=1 smix=9 fixcte sw=5 rev=1 name=flap inh=0 offset=269
chanoutmgr chanout=1 trans=3 reverse rev=1
chanoutmgr chanout=1 trans=4 chantrim offset=82
chanoutmgr chanout=1 trans=5 chanbounds max=1024
chanoutmgr chanout=2 cname=voletD
chanoutmgr chanout=2 smix=0 straight sw=15 rev=0 rate=30 name=aileron inh=0 in1=0 offset=0
chanoutmgr chanout=2 smix=1 straight sw=6 rev=1 rate=-40 name=snap inh=0 in1=2 offset=0
chanoutmgr chanout=2 smix=2 straight sw=15 rev=0 rate=-54 name=bfly inh=0 in1=1 offset=-303
chanoutmgr chanout=2 smix=9 fixcte sw=5 rev=1 name=flap inh=0 offset=-269
chanoutmgr chanout=2 trans=3 reverse rev=1
chanoutmgr chanout=2 trans=4 chantrim offset=-154
chanoutmgr chanout=2 trans=5 chanbounds max=1024
chanoutmgr chanout=3 cname=aileronD
chanoutmgr chanout=3 smix=0 straight sw=15 rev=0 rate=82 name=aileron inh=0 in1=0 offset=0
chanoutmgr chanout=3 smix=1 straight sw=6 rev=1 rate=-23 name=snap inh=0 in1=2 offset=0
chanoutmgr chanout=3 smix=2 straight sw=15 rev=0 rate=51 name=bfly inh=0 in1=1 offset=880
chanoutmgr chanout=3 smix=9 fixcte sw=5 rev=1 name=flap inh=0 offset=-198
chanoutmgr chanout=3 trans=3 reverse rev=1
chanoutmgr chanout=3 trans=4 chantrim offset=235
chanoutmgr chanout=3 trans=5 chanbounds max=1024
chanoutmgr chanout=4 cname=prof
chanoutmgr chanout=4 smix=2 straight sw=15 rev=0 rate=80 name=prof inh=0 in1=2 offset=0
chanoutmgr chanout=4 smix=6 straight sw=15 rev=0 rate=-19 name=bfly inh=0 in1=1 offset=-162
chanoutmgr chanout=4 trans=3 reverse rev=1
chanoutmgr chanout=4 trans=4 chantrim offset=-246
chanoutmgr chanout=4 trans=5 chanbounds max=1024
chanoutmgr chanout=5 cname=derive
chanoutmgr chanout=5 smix=2 straight sw=0 rev=0 rate=80 name=deri inh=0 in1=3 offset=0
chanoutmgr chanout=5 trans=3 reverse rev=0
chanoutmgr chanout=5 trans=4 chantrim offset=-18
chanoutmgr chanout=5 trans=5 chanbounds max=1024


Aerobatic glider and RCHv2

Yes.... that was the first flight with a more serious glider (jedi 4 home made), with 6 channels (2 ailerons + 2 flaps + elevator + rudder). The radio has been configured with several mixes and settings to work good enough for this model type. Here are some pictures, a video demo.



The gliders has 6 channels, and a Assan mini 6ch receiver. Ok, do not do like me, use a more long range receiver. The mini is supposed to be 500-800m range, which can be limited for big gliders. I did not fly very far, but did not had any problem with that configuration.

RCHv2 has been configured to make those mix working: butterfly (airbrake with flaps+ailerons), flaps (with flaps to ailerons), and snap flap (elevator to flaps & ailerons).


See this video foa a demo of those mix.


And also, I was lucky today. After 30 minutes fly, my receiver battery went below 3.2v ! The cells were too old obviously, my fault I should have replaced them. But I was very lucky to be able to bring back without damage the glider, with only 2 mm movement on one aileron and flap. Elevator was still working fortunately. And Assan receiver mini-6 worked still nicely even at a so low voltage, and *without* condensator. Well done Assan !

The next goal is to fly an aerobatic glider (4 wing servos, 2.50m wing span) with the summer version of RCHv2.
Many changes and bug fixes have been done in the software. The USB-serial communication between PC and TX is very convenient, but can be a headache in some cases to debug. Hopefully, it now works pretty well, even with large model configuration.
The PC configuration now support names for Channel and smix/trans. Several parameters have been added to smix type "straight" such as offset, inhibit, switch, rate , etc... This smix "straight" is the most simple one, but already permit a lot of things, as the following mixes below.
The aerobatic glider (Jedi) is now ready to fly with those mixes (in addition to the aileron/elevator/rudder):

- flaps (with flaps to ailerons),
- snap flap (elevator to ailerons+flaps)
- butterfly with elevator compensation.

Flap and snap flap can be triggered by a switch. Only 2 switch are installed on the TX currently anyway.

To recap the possibilities of the RCHv2 radio, based on an Atmega 644:
- 8 analog channel
- 6 switches (or more)
- high number of "smix" or "trans" function can be configured. Right now the only limit is the SRAM more than the CPU,
- support various transmission types: PPM, O24RCPv1 (XBee), RCHv2,
- TX configuration through PC with a graphical user interface.

More on fly test soon.

Some screenshots of the PC appli

Here are some screenshots of the application running on the PC. The radio is connected to the PC through a serial/usb cable. Each change done within this interface is applied immediately to the radio. Each model configuration can be stored/retrieved, they are just plain ASCII files.


The first tab is for stick configuration, it allows to calibrate the stick and set various positions:


Next tab allows to configure channels (servos). Each channel(servo) is shown in a row with all its mixes and settings that have been configured. By clicking on a button, the configurable settings of the mix are shown. Each mix has its own settings, they depends on how the function has been implemented within the radio.


Each servo may have any number of "smix" and "trans" functions. A "smix" defines a mixer, that means that this function will simply add a value to the current servo position. Several "smix" will be added together, this can be used for instance to define Vtail, snap, or diff or any function that need to add or sub some input to the current servo position.


The "trans" type allows to transform the servo position. For instance to limit the course, or to reverse, to adapt the servo pulse, etc...

First flight with an airplane

Today, I flew an Acromaster with the radio RCHv2 (5 servos). It worked like a charm. No interferences, no problems at all. I used the new program interface I developped for PC for programming on the field. I was a bit afraid to bring a PC to the field, because of the screen brightness and the Sun. But a neetbook with good screen, like the Samsung NC10, it's ok and very usable. Even if the software interface is not tuned for high contrast (one more thing in the todo list), it is still readable and can be used to tune the settings at the field.
With the new radio, I found the plane more precise and accurate and more confortable than with my Futaba 12Z... Strange isn't it ? Probably the feeling is due to my happiness to fly with the radio and also may be 2.4Ghz transmission.

Very short howto build RCHv2

Withing few hours, provided you have the right components, you can build your own RC transmitter.

First, an important component is the transmission itself. Any module with PPM signal as input can be used. For its low cost, I choosed the Assan module (Hack version X8D) with Assan receivers. Cool price and so far works fine. It is powered with 5V.

The transmitter box is a very low cost transmitter such as those sold for RC simulator (FMS) http://www.flashrc.com/bmi/2637-gamepilot_boitier_simulateur_usb.html . Remove everything except the sticks and switches of course:

The micro processor is an Atmega 644 DIP, with the external crystal and 2*22nf condo. It must be flashed with the RCHv2 software:

Two small board are screwed in the plastic box, one for the micro-controller, the second one for the micro SDcard and the 5V power regulator. Do not forget the led also on the transmitter front.


One the right side, the UART plug to connect to the PC for the radio configuration (it's hidden on the picture between the protoboard):

Connect all the sticks, switches, the Assan module and SDcard board together:

And that's it, the last step will be to close the box and to configure the micro processor with the PC to set the mixers and settings: