Product for FPV Soarers: FPV Variometer, final prototypes available. See the videos - RC Groups
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Sep 13, 2008, 04:53 PM
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trappy's Avatar

Product for FPV Soarers: FPV Variometer, final prototypes available. See the videos

** NOTE **: See last post for ordering details. Limited number available for now.

Hi Guys,

I started a similar thread here:

What I'd like to present here, though, is an idea I've had while braining a little more about the issue. The potential product I've come up with could be cheaply manufactured and would present a huge benefit to FPV soarers.

Wouldn't it be possible to create a device that acts just like a microphone, but actually produces a vario sound based on the increase/decrease in height your model has. This "microphone" could be used alongside any OSD or any FPV setup, all is already there. The chip should produce the vario sound (lower tone for decrease, higher tone for increase in height) and generate an audio signal identical to the one a TinyMic produces. Hook that device up to the FPV TX and then hear the sound through the goggle-earphones on the ground.

An additional feature would be a passthrough connection to a microphone, and the chip mixes both channels into one.

[FPV TX]<===(audio channel)===>[Vario Sound Device]<===(audio channel)===>[TinyMIC]

The altitude sensor on board would need to have a high sensitivity (~5-15cm) and the vario sound range should adapt itself to thermal conditions (8m/s lift in good conditions produces same sound as 3m/s lift in bad conditions).

Who would be interested in such a product? Anyone that would be willing to make one of those?
Last edited by trappy; May 08, 2009 at 11:29 AM.
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Sep 13, 2008, 05:06 PM
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PeteSchug's Avatar
Check out the Picolario.

It's a stand alone vario that also monitors battery voltage and altitude.

Nice female voice saying. "Attention: Your battery is at 5.9 volts."

When you go up or down it plays a musical arpeggio, either up or down and the rate of the music tells you how fast you are going up or down.

I like it better than my Eagle Tree Seagull thingamabob.

A mere 400 bucks without the TEK probe.

Sep 13, 2008, 05:21 PM
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trappy's Avatar
Hi Pete,

I know of the varios that are currently available. What I'm looking for is avoid having another ground station and another radio channel. Besides, the cost of the device I'm suggesting is maybe ~$50-75 if produced commercially, not $400
Sep 13, 2008, 06:07 PM
SB-28 UK Display Pilot
GeeW's Avatar
There is a matchbox sized vario available that clips to a pilots hat for fullsized use Sorry I cant remember the name at the moment. All you'd need to do is tape your mic to it. From memory its about $160 ish.
I'm working on a similar project using a 3.7m E glider.
One are not very likely to get a good vario for $50 anywhere..more like an electric Cosim than a Cambridge!

Last edited by GeeW; Sep 13, 2008 at 06:15 PM.
Sep 13, 2008, 06:56 PM
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trappy's Avatar
Well, the sensor itself is only around $20:
Sep 14, 2008, 02:48 PM
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Patscherpofel's Avatar
I also wish for this for a long time,
and I have the same opinion...I dont want to add another extra transmitter onboard has to be integrated in the video transmission and the osd

people who would use this vario will go for extremely long have 2 different systems onboard for this would not be ideal

I did my second full sacle sailplane flight last St.Moritz in the middle of the alps...we climbed about 2000m in just 15min...since then I dream of these vario sounds
Sep 15, 2008, 01:14 PM
Registered User
I came up with a ultrasonic terrain alarm a while ago, that beeped when you are low.

I have not used it in FPV because my video tx doesn't have working audio...

Oct 11, 2008, 08:48 PM
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trappy's Avatar
great news. I couldn't let the idea rest so I posted a project on and a electronics guy in the philippines who is also a paraglider pilot made a bid The minimum order would be 10pcs.

In short: He'd be designing an audio variometer that can be plugged into ANY FPV system, regardless of frequency or OSD being used. It will tap into the audio channel of the tx/rx and help you locate thermals or downward air movement. This enables you to stay in the air longer or, when using a glider, gain altitude without using engine power. You can connect your TinyMic to the vario and the sound will be mixed. No additional power supply needed, the vario will also be tiny enough to fit anywhere on your plane where you placed the tinymic.

Longer, more detailed version of the idea:

The bid was as follows:

For his time: $600
For the PCBs: $110 (10 pcs)
Components: $80 per vario

So a rough estimate would be around $100 each plus the development cost spread among all, which will be significantly cheaper than current market systems AND it saves you one downlink. The more join, the cheaper it would get. Anyone interested?
Last edited by trappy; Oct 16, 2008 at 06:35 AM.
Oct 12, 2008, 10:43 AM
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The tones would have to be set for the individual. Some of us have high frequency hearing loss ya know...........
Oct 12, 2008, 12:14 PM
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trappy's Avatar
Randall, not sure I will be able to integrate that into the tight budget Do the market-varios offer that?
Oct 12, 2008, 01:09 PM
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Will this sound similar to a vario in a real life glider? In both type of sound and how the bleeps are spaced or timed?
It would be nice to not have to learn another standard, such as music speed
Oct 12, 2008, 01:13 PM
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trappy's Avatar
Hi Jan,

Thanks for your interest!

Yes! It will sound exactly the same. The task will be to copy exactly the vario sound and also follow the "international standard" in terms of signals. The reason why a custom-built is cheaper is because FPV flyers already have everything in place (rx, tx, headphones) except for the vario. We could save weight, battery and space, besides money, also, because the vario itself is quite small.


Old Oct 12, 2008, 05:31 PM
A moderator felt this post violated the following rule: Excessive Advertising (Over-competition). It is temporarily hidden while billpa edits it.
Oct 12, 2008, 06:14 PM
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Patscherpofel's Avatar
Originally Posted by billpa
If total energy compensation is required, the OSD + Glide Data Recorder is a step up from this.
I would defiantly spend that money for a good Product
but I probably wouldnt put my name in the list before I dont have more detailed infos, and can be sure it will work like I whish for
any chance to see what all this could look like?

It makes sense to have the vario integrated in the osd for sure
(switching it on and off, mixing it with the real audio...etc)

but I am not sure if I understand this right...
the 177US version has a vario but no total energy compensation?
What is the difference? more accurate?
And is there a total price for that?

cant wait for this little toy to make fpv soaring finally a more real experience
Oct 13, 2008, 04:10 PM
billpa's Avatar
Patscherpofel, that is correct. Eagle Tree calculates total energy using an airspeed sensor (and Newton's laws). The total energy factor is fully configurable even when you are in the air.

The Glide Recorder contains both a high resolution altimeter and airspeed sensor, and costs $220USD. So, the complete package should be $220 + $70 (and it also displays airspeed).


Bill, for Eagle Tree

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