thUndeadMod v3.4 - openLRS S**T just got real :)

[Cat695]

just reflash both tx and Rx with 3.3 and RSSI on pin 7 is solid as a rock

[Splashy]

just reflash both tx and Rx with 3.3 and RSSI on pin 7 is solid as a rock

I would advise against this. The RSSI is not working properly on pin 7.

On 3.5 I found the RSSI was very solid (and working) on pin 1. If there had been any glitches then the RVOSD would have jumped into Return to home mode and that causes an audible glitch as the servos twitch. This happened on 3.3 but not on 3.5

[Cat695]

I have another Rx arriving tomorrow Trevor so will try that one...I might just have a dodgy Rx

[papa_lazerous]

I have another Rx arriving tomorrow Trevor so will try that one...I might just have a dodgy Rx

Extremely unlikely to be a hardware issue mate, I assume you protected the Rx with the heatshrink I sent you? Running it naked is asking for trouble.  I'd be inclined follow splashy's advice and run the latest firmware. Perhaps try with stock antennas instead of the ones bought from Simon and then range test. The antennas are an unknown in this equation, I'm not questioning their quality but trying even the stock ones may yield a different result possibly isolating an issue. Also you remember when you had incorrectly selected 3.3v and not 5v when flashing. You are set at 5v 16mhz pro mini when flashing BOTH the Tx & Rx? Just double checking to make sure we are not missing something obvious

[Cat695]

Yes mate it was one of the first things I did was put on that heat shrink

Mihai gave me the same advice on the antennas so stock went back on and will carry out a range test today....but the voltage still drops.

And yep I have reflashed both Tx and Rx with 3.5 and yes John I ensured I was using the 5v 16Mhz (mega328 one)....after a comment Ian made I even ensured the FTDI board remained perfectly still when flashing.

I have a video that I will add once its uploaded guys so you can see me flashing (the Rx that is not getting my todger out  :P).....I didn't show it but I defo had 5v 16mhz mega328 selected (the USB is one I use for an SD card reader)

I want to thanks you guys for all your help by the way!!!

Its my last day at work today for 2 weeks so will be back soon to continue the saga (we're off go karting and the boss is paying!!)

OpenLRS Rx flashing FW version 3.5

[webe]

Hey all,

here's my research results from yesterday. After crashing my short range FPV plane and waiting till glue hardens I hooked up OLRS with CL-OSD, flashed them both with latest firmwares. My multimeter have shown very stable RSSI output on PIN1 - good job Mihai!

But... CL-OSD was very jumpy... Well, that's very logical - you can't reliably read voltage encoded as PWM wave using ADC. So I did a lil research on low pass filters and made simplest one - RC low pass filter (resistor in series and capacitor in paralel to the ground). After doing some math I've come to values of R=20kOhm, C=2.2uF. If PWM is really ~490Hz then i got cut-off frequency of about 7Hz and 0.1s settle time. After connecting OLRS to CL-OSD using that filter I got smooth changing RSSI values on my OSD.

PS. Mihai, I've just put a small amount of funds into your beer fund. Thanks for your hard job! Go and have a beer NOW ;)
PS2. Never ever fly FPV with uncharged ground station battery - that was the reason I lost my video few hundred meters away and crashed my new plane. I'm using 7Ah lead battery (gel type) to power my ground station. Before launch it showed ~11.5V, after less then 10min of flying my GS shutdown and voltmeter were showing ~7V  >:(

[Coyote]

Mine was a bit jumpy at first, I tried a 10k resistor and 2.2uf cap which gave me the best result for smoothing, but I think Ill add the Opamp Papa suggested to me

[thundead]

@webe, cheers for the Beer :D I'll add you to the infamous pringles hall of fame list :D

@Coyote, papa, splashy: glad its working ok for you.

@Cat, if the new rx doesn't work we'll debug the thing over skype tonight after 9 if ur up for it.

@everyone lol : Thinking of adding this things onto the configurator:

1. RSSI debug via serial  monitor
2. Save and Load function for your configs (this way I can debug things better)
3. any ideas welcomed

what else do u think is missing from the configurator ? 

[papa_lazerous]

Mine was a bit jumpy at first, I tried a 10k resistor and 2.2uf cap which gave me the best result for smoothing, but I think Ill add the Opamp Papa suggested to me

I'll expand on the op-amp, I made buffer using a LM358 configured as a voltage follower.  The great thing about using a buffer like this, is that it solves any issues with the OSD putting too much load on the Rx which can cause an unstable RSSI.   Even if you continue with a filter (which I don't think is needed) a buffer is a must as it has such a high input impedance the Rx has to do no work to drive the input which means you get a nice reliable RSSI all the time.

The schematic and wiring diagram I made where drawn on a piece of paper then photographed on the quick to share with Thundead originally, but I have shared with Coyotee too.  So if you can suffer the low-tech diagrams carry on reading....



Ok the top sketch shows you whats going on in the circuit as a schematic.  And the bottom sketch shows you how to connect your wires to the op-amp (note pin1 is the top left, I tried denoting it with a big black dot but it might not be obvious)

NOTE:  Do not substitute for an op-amp other than the LM358 just because the guy at maplins says it will be ok ;)  This opamp has a quite special property, which is it will accept an input that can be the same as the negative power rail.  other op-amps that are powered by 0v GND that recieve a 0v input go crazy and output garbage which would be no good for us. with only +5v to GND to play with there isn't much headroom to use any other op-amp.

Below is a picture of my finished buffer,  I honestly think I was guilty of over-kill with the ferrite bead so its entirely optional.  I bent the legs out flat on the op-amp and soldered directly to the chip, then used some hot glue to protect and hold everything in place, then I used heatshrink that I warmed slowly.  The best bit is that the hot glue re-melts and as the heatshrink closes up the excess glue oozes out.  and you are left with a small well protected buffer that looks professionally made and is very light.



If you guys need more info I guess I can make another thread and do a video on how to make one, let me know if thats needed??

I take no credit for designing the buffer as it's merely an op-amp configured as a voltage follower.  Anyone with more than a passing interest in electronics knows how to make one.  The hot glue and heatshrink was my idea though (probably been done elsewhere though)

[Cat695]

Right guys I'm off to go fly


Got another Rx flashed to 3.5
Did numerous range tests this afternoon and it doesn't drop out (but when connected to my multimeter still drops to 0) so only one way to test this baby is to fly!

This is my setup on EZ*2 (CG as per manual)

Battery (3S 2700mah) to EZOSD current sensor to EZOSD to VTX (5V camera in there to)

current sensor splits off to

8.5 amp BEC which powers Rx on rear of plane
ESC which obviously powers motor (with + pin removed from the servo cable and taped down)

Adjusted TX so it always points up

Rx Antenna is straight up (I'm using the 459 ones from splashy and Simon)


will fly LOS to trim out.

[webe]

@Cat, if the new rx doesn't work we'll debug the thing over skype tonight after 9 if ur up for it.

thundead,
can we have a chat on skype later today? I wanna discuss some ideas with you I have on mind.
If you interested, PM me your skype contacts. Ill be back in 2-3 hours.

[Coyote]

Ok, got up too late after a night shift to range check, but I did have 30min spare to make the RSSI buffer.





After I initially turned it on, things were not good, the RSSI bounced from 3.12v to 0.04v, just the same as Cats, but then I  unplugged plane, plugged it back in, and every thing is fine :)

RSSI holds to within 0.03v with 2.2uf cap on the RSSI input and Ground

Tx power Off / On RSSI returns to max value and holds

Rx power Off / On RSSI returns to max value and holds

[Cat695]

Ok guys just back from a practice and a range test

Lost control of the plane at about 300m (flew beautifully inside 300 might I add), and inside of 300m the motor kept cutting out about every 30-40 secs and then starting up again after about 1 sec.......

after recovering plane (didn't crash thankfully just landed softly again) I gave my spotter the Tx and drove off about 600-700m...and nothing.....everything still powered up and can still get Vtx picture but no signal (red light on Rx).

This is on the NEW Rx I got today!

came back cause I was starving  :(

[thundead]

Hmm something is seriously wrong somewhere in your setup. what antennas did you use ?

I'll do a range test tomorrow with the the latest fw and see how it goes.

Ok guys just back from a practice and a range test

Lost control of the plane at about 300m (flew beautifully inside 300 might I add), and inside of 300m the motor kept cutting out about every 30-40 secs and then starting up again after about 1 sec.......

after recovering plane (didn't crash thankfully just landed softly again) I gave my spotter the Tx and drove off about 600-700m...and nothing.....everything still powered up and can still get Vtx picture but no signal (red light on Rx).

This is on the NEW Rx I got today!

came back cause I was starving  :(

[Splashy]

Ok guys just back from a practice and a range test

Lost control of the plane at about 300m (flew beautifully inside 300 might I add), and inside of 300m the motor kept cutting out about every 30-40 secs and then starting up again after about 1 sec.......

after recovering plane (didn't crash thankfully just landed softly again) I gave my spotter the Tx and drove off about 600-700m...and nothing.....everything still powered up and can still get Vtx picture but no signal (red light on Rx).

This is on the NEW Rx I got today!

came back cause I was starving  :(

Regarding the EZ* cutting out and coming back on again. I do not know the answer to this but had exactly the same problem with mine. There did not seem to be much to indicate what was wrong .. it did not always cut off in a steep climb for instance, and it seemed to do it in random orientations (so not RX antenna being blocked).

I did two things .. first was to add an extra air inlet to the motor. I am using a brushless in runner and I thought that it might be getting too hot. The second thing (and I think this was what did it) was to replace the ESC with a big one .. 60A (from the original 40A Flyfun). My EZ* does not cut out like this anymore.

If you need a new ESC then please let me know .. I have a few spares (80A, 60A, 30A, 18A) Plush