FrSky telemetry

[iter]

This may belong in the boost glider section, then again it may be of interest to the wider community so I'm putting it here.

I've been using FrSky RF modules and receivers in my electric R/C airplanes and RCRGs for a number of years now and am very happy with their products. I recently bought a new Taranis TX (https://www.alofthobbies.com/frsky-taranis.html). The hardware has built-in support for telemetry; the software is open source.

TX can display telemetry in real time on its LCD, as well as log it to an SD card. I have also configured it to audibly announce altitude when I depress a momentary switch, so I can keep my eyes on the model.

The image is a plot of a recent electric glider flight. It graphs Relative Signal Strength Indicator (in dB) to altitude in (in m). As one might expect, their relationship is inversely proportional.

Other sensors are available for this system, including (supposedly) a GPS unit, though I'm still looking for a retailer who has one.

Nominal range the manufacturer advertises is 2km, though this number refers to horizontal distance at low altitude (<<1000'). I've seen reports of people flying FPV setups at significantly longer ranges, and with clear (vertical) line of sight I expect even greater range.

I plan to fly this setup at Snow Ranch tomorrow in one if my RCRGs.

Ari.

 

[BEC]

That is slick! I had gone as far as getting the bits to convert an old Hitec transmitter to 2.4 GHz using FrSky equipment when the rocket bug bit me back and that project along with many other airplane-related ones now languishes.

One more thing to look into.....

 

[Winston]

I've been using FrSky RF modules and receivers in my electric R/C airplanes and RCRGs for a number of years now and am very happy with their products. I recently bought a new Taranis TX (https://www.alofthobbies.com/frsky-taranis.html). The hardware has built-in support for telemetry; the software is open source.

Same here, a FrSky 2.4GHz TX module for my JR TXs, and a 70MHz JR synthesizer module for any-channel 70MHz ops. Been drooling over the Taranis, but ask myself "how many more TXs do I actually need" and the answer is, unfortunately, "none." If I was starting out, the Taranis would be what I'd buy. At its less than $200 retail price, it's an absolute steal.

 

[TheTellurian]

Hi Ari
You showed velocity in the graphs on one of your other threads, can you explain how you did that given theres no airspeed sensor?


Richard
Waiting for Horus op: :yawn:

 

[iter]

awk 'BEGIN{FS=","} NR!=1 {alt=$(14)*3.2808399; split($2, t_cmp, ":"); t=t_cmp[1]*60*60+t_cmp[2]*60+t_cmp[3]; if (alt!=last_alt) printf("%f, %f, %f\n", $2, t, alt, (last_alt-alt)/(last_t-t)); last_alt=alt; last_t=t}'

Short answer: differentiation. I'm graphing vertical speed rather than (forward) airspeed. AWK code above goes through Taranis .csv file (sample below). It cleans up redundant records; then it takes the difference in altitude between last two valid data points and divides it by the time difference between these data points: dv/dt.

Date,Time,SWR,RSSI,A1,A2,GPS Date,GPS Time,Long,Lat,Course,GPS Speed,GPS Alt,Baro Alt,Vertical Speed,Temp1,Temp2,RPM,Fuel,Cell volts,Cell 1,Cell 2,Cell 3,Cell 4,Cell 5,Cell 6,Current,Consumption,Vfas,AccelX,AccelY,AccelZ,Rud,Ele,Thr,Ail,S1,S2,LS,RS,SA,SB,SC,SD,SE,SF,SG,SH

[..]

2014-03-08,13:23:54.420,0,65,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 61.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-2,-1024,36,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:54.520,0,65,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 61.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-4,-1024,39,3,-32,-175,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:54.630,0,65,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 61.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-2,-1024,30,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:54.730,0,73,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 61.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-4,-1024,8,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:54.840,0,73,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 61.81, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-2,-1024,5,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:54.950,0,73,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.06, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-2,-1024,5,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.050,0,73,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.06, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-2,-1024,4,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.160,0,70,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.06, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-2,-1024,4,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.260,0,70,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.06, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-4,-1024,4,4,-33,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.370,0,70,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-4,-1024,4,3,-34,-174,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.490,0,70,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-2,-1024,5,3,-34,-173,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.610,0,69,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-4,-1024,50,3,-33,-172,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.730,0,69,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-2,-1024,50,3,-34,-173,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.850,0,69,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.25, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-2,-2,-1024,91,3,-34,-173,-1024,0,0,0,0,1,1,-1,-1
2014-03-08,13:23:55.970,0,69,6.47,0.00,2000-00-00,00:00:00,002.0000-,002.0000-,000.00, 0.00, 0.00, 62.31, 0.00,0,0,0,0,0.0,0.00,0.00,0.00,0.00,0.00,0.00,0.0,0,0.0,0,0,0,-1,-2,-1024,97,3,-34,-173,-1024,0,0,0,0,1,1,-1,-1

 

[TheTellurian]

Damn thats genius man! :jaw:

All I know about awk is awk 'begin ffip>bork, barf=kak'. Have to up grade the Linux and look into that. [yah rightc:]


Richard

ps, Its been my intention to stuff a FrSky Rx into one of my rockets with a vario sensor, now I can calculate how fast i'm losing that rocket. :wink: