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Posted by zenoid | Apr 27, 2014 @ 02:28 PM | 4,149 Views
Lately I've been busy redoing the vario sensitivity and added the FrSky protocol so I can use my custom GPS vario with my brand new Taranis. I also validated the vario on a JETI DC16 radio. So now i don't have to BT link my smartphone to my radio, thx to FrSky and JETI we can have a proper vario sound and some nice speeches. I hope FrSky will add an "airspeed" field in the protocol. For the moment I just replace the GPS ground speed available with my sensor airspeed.

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Posted by zenoid | Jul 23, 2013 @ 01:42 PM | 5,845 Views
Finally wrapped all together

The sensor board, custom vario-GPS-logger-airspeed... :

Close up on the measures :
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Posted by zenoid | Jul 05, 2013 @ 07:36 AM | 5,493 Views
Some club mates asked for a JETI adaptation of my sensor board. Since it's already working with FrSky radio and they have the same kind of serial lines I grabbed the JETI EX protocol documents and write the JETI mode. So here is the result on a JETIbox. It displays Vario, indicated airspeed, altitude and temperatures. I don't send GPS data yet, I fear that doing this will result in a to slow Vario refresh rate. GPS data are therefore only stored localy on the electronic board on a SDcard.


(On those pics temp is -45C because a component is missing on the hardware)

Each frame sent got old and new protocol parts. So here is the old way :
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Posted by zenoid | Jan 30, 2013 @ 11:02 AM | 6,618 Views
It's winter here in France, I'm frozen and grounded so it's time for some writings...
I've managed to make a few pcb of the telemetry board last year and tested it within my DG600. It run as expected, nicely. The bird is equiped with the telemetry board underneath that is itself tied to the Pitot tube and the TEK probe you can see on the following pics.
In blue wires the temperature probe. Gold connector for the GPS antenna.

One TEK probe just behind the pilot for a total energy variometer.

One Pitot probe for air speed.
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Posted by zenoid | Apr 03, 2012 @ 03:40 PM | 8,119 Views
Once you have filled the SDcard with flight logs of your beloved sailplane, it is good to be able to store them and see for each one their statistics and 3D traces. So I wrote a little tool that do just that.
First import a log file :

then see the graphs and statistics (not finished yet here). You can view 2 curves type at a time from the selector on the left, then you can pan and zoom the graph at will :

Then you store all those log and kml files produced here. There are 3 tables, one for the sailplanes, one for the pilots, one for the logs. Pressing the store button on the graph tab will allocate the log to a paired pilot/glider :
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Posted by zenoid | Feb 27, 2012 @ 04:03 PM | 8,408 Views
First get a reading of the previous post to a have the whole picture...
While I was waiting for a new set of pcb to test a new gps chip, I decided to revamp the menus and settings. I also introduced some new stuff after I read a few interesting thread in the cross country soaring forum (more on this later) :
RC XCsoaring.
So first to be able to debug the application more easily, I wrote a little glider animator. By tilting the smartphone you can turn, climb or go down, so you can test all your vocal and alarm setting, and get used to the race module. The animator is not realist at this point but I'am working on it. It would be fun to have a real flight model behind that.
GBW application glider simulator (0 min 45 sec)

After having read the thread mentioned above, I decided to take a look at polar curve and speed to fly. All those notions are well established in the real rc glider world, not yet in the RC communauty. But with the introduction of GPS assisted XCountry and GPS race in europe, those kind of data are of value. The glider polar curve is the one that connect air speed and sink rate (in stable atmosphere) from where you can compute many thing like the ideal speed to fly on a race, etc... So why not trying to get experimental data and build this curve in real time ? I decided to implement a polynomial approximation from the cloud of points(airspeed, sink rate) gathered during a flight (I carefully read that document http://xcsoaring.com/techPicts/Edwar...nce%20test.pdf). After some math stuff, you have a,b and c of the polynome. If you don't want to measure it, you can directly enter those coeffs from the menu. You can also set the Mc Cready in auto mode or change it by yourself. If you select to build your polar, you can specify the record length in seconds (FIFO buffer). In the end you can also take a look at the altitude, vario, ias, polar curves. All this is WIP and waiting for comments enventually.

Posted by zenoid | Jan 29, 2012 @ 04:23 AM | 9,580 Views
Here just a glimpse to my android software (here a Nexus S). First you'll see the sensor board plugged to the FrSky D8R receiver. Then I connect the droid to the FrSky Tx thanks to a Bluetooth module. No GPS connexion in the first movie, so you don't see the glider position next to the phone position. I zero the altitude and show the map's menus.
Android RC glider software (0 min 48 sec)

Second video : launching the app, connect to Bluetooth-FrSky-Sensor board, showing an active GPS connection, you see the glider position next to the phone one (here both the sensor board and the phone are inside the house next to the window). In magenta you see the GPS height and ground speed. You see from top to bottom : QFE or glider elevation (you can zero it), air speed, vertical speed (you don't hear the vario sound as it is varying around 0.1 m/s), averaged 10 seconds vario, GPS height and ground speed, distance from droid phone to glider.
android to FrSky RC glider software - BT connection (0 min 39 sec)
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Posted by zenoid | Nov 18, 2011 @ 04:06 PM | 9,495 Views
Some update of the hardware side of things.

From left to right :

FrSky telemetry receiver D8R - my new sensor board - the last prototype.

I've made the new prototype a 4 layers one instead of a 2, diminishing the size plus components are better organised this way. Analog signals from sensors have a better dynamic so the average vertical speed noise is very low. At rest, the vario move around an error of a few cm/s.

Specifications of the new board :
- baro altimeter 0 - 9999m
- variometer, with TEK eventually, low noise
- airspeed baro sensors
- GPS (LEA6-H) with active antenna, very sensitive
- temperature sensor
- micro SDcard / datalogger
- mini USB, device type that make the board a MSD and a USB virtual serial port.
- configurable serial port(from ini file in SD) (TTL) that goes to FrSky or any modem.
- aux. analog input
- pwm input for throttle survey

Flight logs are CSV types and are Logview enabled, one line is :
$1;1;;151111;152819;4600.42;502.50;00291;000;000;0 7;2.64;1;0.01;0.00;240.35;11.72;0.0;00;0;0.0000 Guess what they mean
Posted by zenoid | Oct 28, 2011 @ 05:02 PM | 10,766 Views
I've had some time to make some works on the android software, it is glider oriented and the goal is still to achieve racing almost like the real ones.
Screenshots here are captured from the dev tool Eclipse and are the images taken from the real device display driver.

The blue circle figures the GPS position uncertaincy of the smartphone (here a Nexus S). Our glider in red gently resting in the backyard.

On the left, we have a QNH altitude of 168 meters (I can reset to 0 and have the glider relative altitude)
IAS show zero km/h.
Vertical speed is zero.
Vertical 10 sec averaged too.
GPS altitude 284 meters.
Ground speed zero.

If I want to add turnpoints on site, I just press menu->create TP and tap where I want to place one. I can place as many TPs as I want. Distances between TPs are shown in the middle of each segment. I can remove or move a TP the same way. The glider will have to pass in each turnpoint radius in the right time windows at the right altitude windows. Altitude, TP direction and distance are spoken by the application. Some sound FX are added for the race and glider VNE and STALL speed.
The variometer play sounds like real glider.

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Posted by zenoid | Sep 12, 2011 @ 02:51 PM | 10,733 Views
Here is the complete setup that I have:

- Cockpit MM modified to carry the FrSky DHT Tx module along with the original 41 Mhz.
I just have to switch bethween modules.
- Serial output from DHT (rs232) that either go to my PDA
- or feed the BT radio module
- then 2.4 Ghz FrSky radio linked to a FrSky D8R
- a sensor board I made that send back GPS, ias, vario, throttle, aux, temp, SD logger...

The BT module has been purchased from this link :
I was surprised that it work strait away from the box. I just plug the GND/5V/RX lines and after a scan my android app is able to connect it.

So left to right :
- my 'XCeasyglider' that carry the FrSky D8R receiver
- the sensor board with pitot and TEK tubes
- android nexus S and the App I show in the last post
- PDA with an app I made. Glidebywire
- Radio cockpit MM multiplex with FrSky DHT inside (white thing partly hidden)
- and far right ; the bluetooth module
Posted by zenoid | Sep 02, 2011 @ 08:47 AM | 10,533 Views
I'am currently porting the PDA software to the android paradygm. I'm now able to connect the FrSky telemetry data channel to my android app via a bluetooth module that grasp the serial frames. Here are some first shots.

Connect menu brings you to a bluetooth scan and connect page.

What you don't see here are the glider, pilot, turnpoint and path icons.
Displayed data are distance to pilot, qfe, ias, vz, avg vz, and gps data for now.

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Posted by zenoid | Jul 13, 2011 @ 03:44 AM | 10,400 Views
It's about time now to open my blog which is a way for me compile the works I've made around my prefered subject : racing big gliders like the real ones do.
So to do that I've developped a telemetry system that give back all the needed information to the pilot :
  • IAs
  • GPS ground speed
  • baro altitude
  • GPS altitude
  • bearing
  • baro vario
  • Throttle position
  • SIU
  • temperature
  • GPS position

The IHM is a PDA running Windows Mobile. A speech synth tells you some information like altitude, name and bearing to next turnpoint and height to turnpoint. A test race I've made with my test pilot :

To test that system without stress I've equiped the now called XCeasyGlider

You see here two probes, one in the front that collect the airspeed as a pressure and a vertical one just behind the canopy that is a TEK for the vario.

Thanks to FrSky and their open protocol, I've rendered the sensor board compatible with this data sheme. So here we have the cockpit MM quasi antic radio with a 2.4 Ghz DHT FrSky Tx inside that give air data to the PDA. The sensor board is plugged inside the glider to the D8R

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