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Re: Lemon Telemetry with ErSky9x

Posted: Fri Feb 01, 2019 8:29 pm
by mentero

Is it normal that nothing is heard if the Vario source value is less than 26 ?

Let me check if I understand this:
Vario source can vary from +1024 to -1024.

+256 - 256 seems like a reasonable input for Vario source, since the increase of number or beeps per second stops at a value of 200, even if the frequency of the beep itself continues to raise. (very, very uneducated guess).

A scaler SC1 = Vspd * 6 gives +240 -240 for a Vspd range of +4m/s to -4m/s. since Vspd is in dm.

Beeps are then heard at zero (?), and then silence up to a input value of 26. That is equivalent to 0.43m/s. Not a very good resolution in an area critical for low altitude thermal hunting.

Maybe I shall go up using a scaler of Vspd * 26 ? That will make beeps at 0.1m/s.

Some enlightment will be much appreciated.


P.S, Note that all this is theoretical, the weather is too bad to go making airborne tests, that will probably solve the issue by ear.

Re: Lemon Telemetry with ErSky9x

Posted: Fri Feb 01, 2019 11:16 pm
by MikeB
The FrSky vario sends the vspd in cm/s, although from my log files, it looks like it goes in steps of 50.
According to the code I just looked at, the DSM telemetry value is multiplied by ten, so is converted to cm/s.
Yes, vario tones start when the source value exceeds 25.
If sink tones are enabled, then tones are generated, spaced a long time apart, when vspd is zero.

A Scaler of vsdp * 6 should give a value of 60 when the telemetry value is 1 dm/s (1 * 10 for cm/s, then *6 in the Scaler).
Again this is theroretical! I don't have a Lemon vario, or Rx with built in vario.


Re: Lemon Telemetry with ErSky9x

Posted: Sat Feb 02, 2019 3:59 am
by Daedalus66

Send me your postal address and I’ll send you a Lemon receiver with vario/altitude.


Sent from my iPad using Tapatalk

Re: Lemon Telemetry with ErSky9x

Posted: Sat Feb 02, 2019 12:05 pm
by mentero

thank you Daedalus for your offer to Mike. I am at least as happy as he is. Maybe more. :lol: :lol:

It seems that my arithmetic is out by a factor of 10. Not too bad, I have done worse than that.

Re: Lemon Telemetry with ErSky9x

Posted: Sat Feb 02, 2019 11:06 pm
by MikeB
Nigel, PM sent.


Re: Lemon Telemetry with ErSky9x

Posted: Mon Feb 25, 2019 12:41 pm
by MikeB
From an Issue on mbtx:
"In every 0x40 record, Lemon is sending down six different data for Vspd, that according to Spektrum documentation correspond to data filtered (averaged ?, differentiated ?) using a time constant of 250ms, 500ms, 1s, 1.5s, 2s and 3s, trading accuracy for delay.
The data with a 250ms filter shows a poor stability. Peaks can be as high as +/- 1m/s, with a standard deviation of 0.38.
If I understand the code right, this is what ersky9x is using in the processDsmPacket function in frsky.cpp

On the other hand, data filtered with 1s, shows a much better behaviour, (max peak at 0.4m/s, and stdev of 0.15) at the expense of the corresponding delay, that I suppose, (haven't tried that yet) less annoying than chirps showing very fast changes that are in fact not happening."

I have added an option, in the telemetry menu, to select which of the 6, filtered value to use for "vspd".
This is included the the "d4" test version I have just posted.


Re: Lemon Telemetry with ErSky9x

Posted: Mon Feb 25, 2019 1:14 pm
by jhsa
Is that only for the DSM telemetry? or does it also affect other protocols??



Re: Lemon Telemetry with ErSky9x

Posted: Mon Feb 25, 2019 4:13 pm
by mentero
Thank you Mike,

The longer filters clearly improve the stability around zero.
Even with that, the correlation of sound and movement when moving the receiver by hand does not seem (to me) very good. I will try to make a video.

No time yet to try the new firmware on a plane.

Minor problem of "d4". I hear some hesitations (not every time) on the welcome message and on the "no telem-m-m-m-etry" message when the Rx or Tx is turned off.
(edited to add: This happens only if the receiver and tx are close together. Go figure.)

@João: Do not know for sure, but I believe this feature is DSM only.


Re: Lemon Telemetry with ErSky9x

Posted: Tue Feb 26, 2019 2:26 pm
by mentero
I recorded a short video to show what I am talking about;

This is the Lemon receiver with "d4" test release in 9XR-pro with Vspd (no scalers) as a source for vario and 0.250s selected. Sounds confusing to my ears.
Choosing 1s filter helps with peace of mind, because there are not so many chirps all over the place, but doesn´t help a lot in understanding in what sense and by what amount the Rx is moving.
Has anybody had better results ?. If so, how ?

(9.39 MiB) Downloaded 24 times

Compare to what is heard in this video recorded with Lemon Rx and Taranis when the author raises the model at time 2.12


Re: Lemon Telemetry with ErSky9x

Posted: Fri Mar 08, 2019 11:48 am
by mentero
After several days of flying with the Lemon vario, I have come up to the following setup, that is working for me.

If you want to use it as a starting point, this is how: (if you do, your comments will be appreciated)

Use ersky9x Version ersky9xProvR222d4 , dated 25-Feb-2019 or newer, found here:

Choose Software volume in the Maintenance menu. If you don't, vario volume input will not change the volume of the tones.

Telemetry vario data is acquired in 0.1m/s steps, and stored internally in cm/s; therefore, 0.1m/s is stored as Vspd = 10
The first tone will be produced by ersky9x when Vario source = 25, therefore a scaler of 2.5 ( Vspd multiplied by 25, divided by 10) can be used
so that 0.1m/s rising makes the first noise.
If you prefer to use a scaler of 3, the first noise will be heard with Vspd = 0.083m/s, but that will not improve sensitivity.
Use an offset in the scaler screen if you prefer the first tone to be heard before of after 0.1m/s. I am still experimenting with that, for now it is set as zero.

Choose a filter (DSM Vario) of, at least, 1s. or greater. I use 1s or 1.5s depending on size and weight of the model.

I do not like sinking tones, unticked the case.
Tone frequencies are set as low as possible. -50 frequency,-20 offset.

I have also used a couple of logical values
L1 avoids the tones when Vspd <= 0. If not used, tones will be heard every two seconds if Vspd = 0. ELE switch is used to cut vario tones. (Review this if you tick sinking tones)
L2 avoids the tones when the throttle is up. (On electric gliders. Change if the throttle stick is used for brakes or spoilers).

(edited: forgot to mention, I opened the receiver and put some very low density open cell foam over the sensor to avoid the air currents inside the fuselage. If you do, take care with the very tiny lugs at the corners.)


Re: Lemon Telemetry with ErSky9x

Posted: Fri Mar 08, 2019 12:16 pm
by bob195558
home built 9xr pro.jpg
home built 9xr pro.jpg (31.98 KiB) Viewed 942 times
mentero wrote:
Thu Jan 24, 2019 5:33 pm
Oopss, sorry I haven't mentioned, :oops: my display is upside down because my radio has the "brains" of a 9XR-pro,
but is in a different case with better sticks, and the wiring was considerably cleaner with the display upside down.

If I remember correctly, there may be an option to flip the screen image 180 in erSky9x.
I think it is in the hidden radio setup window.

Re: Lemon Telemetry with ErSky9x

Posted: Fri Mar 08, 2019 12:29 pm
by mentero
Yes, that is what I use.

Works perfect, except on the bootloader screen. The "problem" only appears if my eeprom is exported and read by a stock 9xr-pro.

Perfect for inverted flight. :D