DIY Telemetry system for FrSky

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Curtis

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Apr 5, 2010, 2:14:49 PM4/5/10
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Bruce,
Thank you for your video out on YouTube. I also speak quickly when I
am excited about something, so I understand. I am very excited to see
what you come up with regarding the telemetry system, including the
Transmitter interface. Thank you for keeping it open for us to
borrow. This is another reason why so many of us are in the hobby to
begin with, we don't want to simply buy something and play with it,
but to build and create and to dream of other things.
Keep up the good work and I will be waiting (mostly) patiently,
Curtis

hillflyer

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Apr 6, 2010, 6:05:07 AM4/6/10
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Hello Bruce and Curtis,

the open standard interface on the FrSky 2way Rx is a great invitation
to come up with creative add ons.
I agree with Bruce about the danger of looking away from the model in
order to check a display on the Tx.
Top of my wishlist is an audio variometer for gliders. I have looked
at a lot of commercial (way too expensive) and home brew gear (not all
the features I like). Also it always involved a separate Tx/Rx return
path for the information, not an ideal situation for small gliders.
(HLG)
So the possibility to have it all integrated into the RC system is
VERY appealing.
There are some really cool digital pressure sensors available that put
the old analog Motorola pressure sensors to shame regarding
resolution, noise and size.
For example the BMP085 from Bosch.
Check out the datasheet at
http://www.bosch-sensortec.com/content/language1/downloads/BMP085_DataSheet_Rev.1.0_01July2008.pdf

Regards
Hannes

hillflyer

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Apr 14, 2010, 2:28:57 PM4/14/10
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FYI, this webpage has an interesting application for the BMP085 and a
PIC.
http://www.pixelproc.net/pic24hj12vario.html
Now one only needs to adapt the code for analog DC output or a 4800bps
serial to interface it with the Rx.

Or, wildest idea yet: integrate the sensor into the Rx! That ought to
be a first on the market: a special glider Rx with integrated vario.
What do you think?

Hannes

xjet

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Apr 25, 2010, 11:12:21 PM4/25/10
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I've had some more thoughts on the telemetry system, as I've been
writing the firmware.

How many people fly on rough terrain where it might be useful to find
your model if/when it lands away from the field?

I know that some cross-country and slope-soaring glider pilots fit
"lost model alarms" in the event that they're forced to land far from
the piloting position. These alarms aid model recovery.

However, what about including a facility that provides a heading and
distance to the model once it's landed (or at least to its last-known
position)?

I was thinking that this would make it much easier to track down a
model that's disappeared from view. It would be quite trivial to
implement and, if I added a GPS module to the transmitter side as
well, your transmitter would keep you constantly updated as to which
way to walk and how far away the model now was as you got closer.

Who'd find this to be useful and are there any other suggestions
before I finalize the software?


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Robert Moody

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Apr 25, 2010, 11:53:06 PM4/25/10
to aardvar...@gmail.com, RC Model Reviews
Do you know how hard it is to find a slope plane that went down just 3 meters in front of you and then bounces 20m down the slope after you lost sight of it. That would increase my flying time by a good 30min cause I would not have to look for it.

hillflyer

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Apr 26, 2010, 7:25:47 AM4/26/10
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The serial interface seems to be begging for NMEA GPS data to be sent
over it....
Jeti has done an interesting implementation in their Duplex system,
but it stops at telling you the GPS coordinates of the lost plane. It
also keeps the last known position in case of a fatal crash of the
model.

Bruce, maybe the 2nd GPS does not need to be integrated in the TX, as
the models donät get lost on every other flight, even on the slope.

Hannes

agib...@gmail.com

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Apr 26, 2010, 9:39:35 AM4/26/10
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I'd agree you don't need the 2nd GPS in the tx. Just have the coords plug into something like Google maps and we can find it. I like the Immersion RC iphone app because of this. Although the iphone has gps so it follows you but a simple map would do no?


Andy
Sent from my BlackBerry® smartphone with Nextel Direct Connect

hillflyer

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Apr 26, 2010, 11:13:51 AM4/26/10
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Correction,
the lost model info is a feature of the new LinkVario from a German
company WSTech.
Go to their website to listen to a beautiful variosound...
http://www.wstech.de/
This vario is using the back channel of the Jeti duplex Rx to send its
stuff down to the pilot.
The only problem is the pricetag... 354 Euro for the Linkvario incl.
GPS, plus whatever the Jeti duplex gear costs.
Way out of my price range...

JomarX

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Apr 26, 2010, 11:54:22 PM4/26/10
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GPS is definitely a plus! Will make plane location easier.

hillflyer

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Apr 27, 2010, 3:05:49 PM4/27/10
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Here is a simple analog Vario circuit that could be adapted to be
interfaced to the AD input of the Two Way Rx.

http://electronicdesign.com/article/test-and-measurement/create-an-audible-vertical-speed-indicator6241.aspx

http://archive.electronicdesign.com/files/29/6241/figure_01.gif

Sorry about the low res. of the gif...

Hannes
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