(05-Jun-2022, 02:13 AM)kafie1980 Wrote: Just go with SBUS and make your life easy. On a small quad like this you don’t need much telemetry and just setup audio alerts for LQ etc on your radio.

^^^yeah, ima just do this. I’m capable of smd work, so I could probably break out a pad if I *really* needed to, but it is not worth it for this bird. It’s not gonna be flying out far enough for me to worry about losing rx signal- in my environment I’ll lose video far before I lose rx signal.

Any kind of smd work tends to turn into a night of cursing and frustration, and then some purchases of replacement parts the next day.

I’d be willing to try for funsies if I had a hot air rework station, but I don’t.

Okies, here’s where I’m at:

The led/buzzer cable that I initially soldered wasn’t long enough. Extended it, all good. Tried to use those purple gummies- there’s no way to shove them through the FC. I mean, I can, but by the time I do they are so mangled that they’re no longer giving me any isolation from my screws.

Okay, I’ll use the included red gummy spacers.

Soldered up my ELRS rx. Every time I set up an ELRS receiver, I reference this page:
https://oscarliang.com/setup-expresslrs-2-4ghz/


Thank you Oscar, you’re awesome.

Unless I want to mount my FC above my vtx (I don’t- vtx puts out more heat than any other component and I don’t want that heat rising up to my FC) then there is no way for me to access the USB port without removing a prop guard. Guess I better try to do my best to set everything up prior to final assembly.

Apparently HGLRC couldn’t be bothered to mirror the prop guards, so the crossbars and little landing feet are gonna all be going in different directions.

Y’know, I’ve been wanting to try a pusher, and the mounting holes on these prop guards go all the way through… all I’d have to do is figure out how to route my motor wires after I flipped them upside down since the motors mount onto the guards…

My motor wires for this build are excessively long for two reasons:

1: I honestly don’t expect this build to stay together very long before I cannibalize it for parts. I’m hoping that I’ll be pleasantly surprised and this thing is awesome, but, I am going into it with a negative bias for a number of what I think are valid reasons.

2: Before I cannibalize it I wanna try turning into a pusher, and that will require some longer motor wires for some creative motor wire routing.

Hi Lemony,

Well, maybe it will last longer than you think.

However, I do think that the weak part is the few bolts that
hold the prop guards to the frame, especially since the motors
are only mounted to the guards with NO support. 

Just a thought    The motors could be supported with a brace
such as this BETAFPV stiffener brace for Beta85X. 

If the frame breaks  where the whoops mount, that will pretty much
take care of that frame, however, if the whoops don't break they could
be used on another frame by simply mounting them under the motor
which is how many of the prop guards mount anyway. 

I’m having some sort of issue with my rx. I’ve flashed this ep2 with rcvr_invert_tx, because I’m connecting it to an sbus pad.

Sbus pad on the fc should be rx2, because tx1 is irc tramp for the vtx.

My Tx16s transmitter is recognizing the receiver when I power it up.

Serial rx is enabled on uart2.

In the receiver section in betaflight, receiver mode is set to serial via uart, crsf as the serial rx provider.

…and I’m not getting any movement on the receiver tab in betaflight.

Wtf am I missing?

Here’s my rx to fc wiring in case I’m pulling a bonehead move and wired it wrong.

Diff All is below. Other important bits: JHEMCU SI-F4 Flytower bits (F411 FC). ESC flashed with Bluejay, 48khz. VTX is working fine and dandy. Betaflight 4.3 RC7.

Haven't set up modes yet because rx is not responding.

Target is MatekF411 because that’s what what little documentation I could find on this old stack says it should be.

All wiring and settings look fine to me. Try flashing Betaflight 4.2.11 to the FC and see if receiver inputs work under that version.

I am curious.   

Is the SBUS pad inverted on that FC ??     

Will ELRS work with an inverted SBUS pad??    


.

(07-Jun-2022, 11:41 AM)iFly4rotors Wrote: I am curious.   

Is the SBUS pad inverted on that FC ??     

Will ELRS work with an inverted SBUS pad??    

Pads marked "SBUS" are always inverted by default on an F4 FC. It is just a normal UART RX pad with an inline hardware inverter to uninvert the inverted SBUS signal that comes in from an SBUS receiver.

The ExpressLRS devs added the "rcvr_invert_tx" option for ELRS receivers to the 2.0 ELRS firmware which when switched on inverts the CRSF signal before outputting it (so it ends up inverted just like an SBUS signal). This then allows the inverted CRSF signal to be fed into F4 FCs which only have an SBUS pad available for the receiver. The inverted CRSF signal then gets uninverted again by the inline hardware inverter on the SBUS line so that a normal uninverted CRSF signal ends up going into the UART on the MCU (which is set in Betaflight to receive a CRSF protocol signal). It's quite a clever way of allowing ELRS to be used on FCs with limited UARTs, one of which only has an SBUS connection.

Hi Snow,

Thank You.  That is a very good explanation; very understandable.  

Whelp. We have another atmospheric river blowing in. It's June, so local rivers shouldn't be on flood watch, but they are, so yay for global warming.

I managed to get two flights in tonight during breaks in the rain, but it's pretty steady buckets of water falling from the sky, so this is a build night. Not a very successful build night though.

I tried downgrading to the last stable version of BF to get this rx to work, no luck. I spent about an hour and a half in the ELRS discord help channel, and we're all just as lost. It should work. I've replaced the EP2 with a known good working EP1 that was on another quad that only has an sbus pad- still didn't work. Hooked up a known good xm rx, and it does work- so it's not the fc. Yay for that!

Okay, fine, for whatever reason this fc doesn't want to work with ELRS. Cool, I'll use the xm. It's a close proximity build so it doesn't really matter.

This bird is getting a dipole antenna because I've destroyed most of my u.fl antennas.

Assembled. Setup. Time to attach props...

...and these 1204 motors apparently aren't high enough for the props to clear the prop guard supports. As a side note, I didn’t use the included motor bolts, because they would have been rubbing all up in my windings. Included bolts were m2 5mm, I used m2 4mm.

Grrrrrrr. Okay. I can switch to 1106 motors, or I can print some 1 or 2mm motor spacers to lift them up. Maybe I’ll end up using those m2 5mm bolts after all, after raising the motors up 1mm.

This bird has officially become my most difficult build so far. Shouldn't be, but it is. Every step seems to cause a new problem.

I *will* get this thing in the air. It's gonna take me a bit though.

I should probably also note that the black tpu V antenna holder is mounted backwards in this build- it wasn’t supposed to be necessary because I was planning on using an ep2 rx with a ceramic antenna, so I went ahead and mounted a ridiculously large capacitor, and was only planning on using that V mount as additional support for the rear ducts since they didn’t have anything else holding them together back there.

(10-Jun-2022, 06:55 AM)Lemonyleprosy Wrote: ...

Assembled. Setup. Time to attach props...

...and these 1204 motors apparently aren't high enough for the props to clear the prop guard supports. As a side note, I didn’t use the included motor bolts, because they would have been rubbing all up in my windings. Included bolts were m2 5mm, I used m2 4mm.

Grrrrrrr. Okay. I can switch to 1106 motors, or I can print some 1 or 2mm motor spacers to lift them up. Maybe I’ll end up using those m2 5mm bolts after all, after raising the motors up 1mm.

...

Hi Lemony,

Now I am a bit confused     

First, why do the props need to be higher than the guards??
On my whooped quads, the props sit inside the duct, below the 
top of the duct. See picture of my Tiny-Black-85 which is 
fitted with 1202 motors. 

So, with the props on, is there clearance between the tip of the
prop and the side of the duct     If there is, then it should be
good to go.  { 2 inch props, correct? } 

If you really want to raise the motors...I have used M2.5 x 5mm 
nylon standoff columns {the M2 bolt will go through these without
hanging up on the threads}...
also, iFlight makes spacers that they call "Motor Guards".  

The problem is that the props are clipping the supports that go from where the motor mounts to the bottom of the ducts- the motors need to be raised a mm or two in order for the props to sit inside the ducts and not hit the supports.

If you look at what I have my motor wires zip tied to- those supports. It’s hitting right where they connect to the duct.

Sick man you got me wanting to build a whoop now too lol. Been waiting for that HDZero nano cam for it.

I'd caution against TPU motor mounts more than 1mm thick. I generally keep mine to just 0.5mm. I've found that any thicker, to use as riser pads which I've tried before, and they get way too smushy at best requiring you to tighten every flight and at worst causing some funky vibrations which is exactly the opposite of what they were meant to do.

Thanks for the advice- I *think* 1mm will give me enough clearance, although if they deflect down at all it may not end well.

If I have to higher than 1mm then I guess I’ll hafta hunt around in my shop for some thicker random plastic that I can cut and drill out.