seems just by skip smartaudio than

I dont have anything close to 1S.
All my 3" are 6000KV max.

This "5A" and "1S only" weird obsession of yours.

High KV 1S 1202.5 use MORE amps.. not less.. to make up for much reduced voltage.

Here is a thought. Skip McDonalds coffee. Spend $5 extra. Get proper 25A+ board thats actually not handicaped. Yes.. 2g more. big whoop.

Prepare for the "1st batch" curse

(24-Apr-2021, 03:12 PM)iFly4rotors Wrote: Using the link provided in the original post, I have found DIFF settings for the CrazyF4 ELRS. Happymodel shows the Betaflight ports tab as follows:  UART 1 is Serial Rx, UART 2 is the VTX (TBS Smartaudio). Even though the Rx is internal, it appears as though it is still taking a UART. The Smartaudio is on UART 2. 

If Happymodel is correct with these Betaflight settings, there really is no UART for a GPS.

Plus there is really only a "Pad" for the RX2; TX2 is really not a pad, but rather just looks like a tiny solder connection.

Call me confused     So...how do you get the GPS wired up and working with this board 

Do we actually need to have the VTX controlled by Smart Audio, or does it default <somehow> to 200mW output/etc ?  If it "just works", that would free up completely UART2.  

While I'm grasping for threads (or ports), will INAV be happy with Smart Audio using the TX port and GPS using the RX port of the same UART if they are configured for the same baud rate <if that's needed> ?

(01-Jun-2021, 07:44 PM)mirov Wrote: Do we actually need to have the VTX controlled by Smart Audio, or does it default <somehow> to 200mW output/etc ?  If it "just works", that would free up completely UART2.  

While I'm grasping for threads (or ports), will INAV be happy with Smart Audio using the TX port and GPS using the RX port of the same UART if they are configured for the same baud rate <if that's needed> ?

Hi mirov,

First, you don't actually NEED SmartAudio, but I find it a pain in the arse to set the VTX with that little button after it is mounted inside the belly of a quad...and...you can't change the setting in Betaflight unless you set up SmartAudio...that is how Betaflight "talks" to the VTX.

Now, SmartAudio may only take on part of a UART, the GPS needs both TX and RX of the SAME UART...and...you can't "double duty" a UART by connecting it to two different components. NO it Doesn't work. 

Crazybee just needs to use a different chip on their next FC...at least an F405 chip which has extra UARTS...an F7 would be better. In my opinion, putting a Long Range receiver on an F4 board with no extra UARTS is just CRAZY...bee. I just don't see the FC as having much of a place. If they want to make something...why not make something good...appealing...  on the next revision, use an F7 processor and U.FL connectors for all of the antennas whether Rx receiver or VTX to facilitate using different antennas. 

Now, I realize that the ELRS receivers are super tiny, but why not make one that fits the standard 26x26 whoop mounting format. It could use just 2 bolts like the Zeus VTX or a more conventional triangle using 3 bolt mounting like a lot of whoop VTXs. There is plenty of room {even in a tiny whoop} for a super tiny receiver.

it'll have 2 full uarts, plus you could softserial the LED pad.

the rx is talking over spi so it won't use a uart.

from the diff on the happy model website, smart audio vtx control is on UART 2.
I bet you could swap things around a bit and move it to softserial. there's a solder jumper, i would guess you could wire the vtx pad to LED.
that'd leave you with 2 full uarts.

(01-Jun-2021, 08:58 PM)p-i-engineer Wrote: it'll have 2 full uarts, plus you could softserial the LED pad.

the rx is talking over spi so it won't use a uart.

from the diff on the happy model website, smart audio vtx control is on UART 2.
I bet you could swap things around a bit and move it to softserial. there's a solder jumper, i would guess you could wire the vtx pad to LED.
that'd leave you with 2 full uarts.

Hi p-i-engineer,

On the one hand I hear what you are saying, on the other hand it seems to conflict with what Crazybee has actually put on THEIR website. Reference the attached graphic taken directly from THEIR website where it CLEARLY shows the Serial Rx as using UART1. Maybe it communicates via SPI, but still consumes a full UART...UART1. 

I realize that SoftSerial is sort of an option, but this is sort of like hacking it. There are no clear instructions on how to do this or how it would work. While some folks may believe that mapping out soft serial is a "piece of cake", many of us may not be that intuitive or have that knowledge. However, I would welcome some good articles or YouTube videos on implementing SoftSerial especially when no pads are available. Also, sometimes any seemingly available pads won't work.  What I find cumbersome is that not all boards have extra pads that can be mapped or remapped...again, there is nothing intuitive here. You have to "hack" around and find some pad that you can solder to...then see if you can remap it to SoftSerial. Am I crazy or is Crazybee crazy. If Crazybee wanted SoftSerial, they should have it implemented it, provided specific pads, and specified which pads to use...like Flywoo does with their FC boards that need a SoftSerial interface.


What confuses me is why one would bother when you can get a good whoop mount FC with plenty of UARTS and just add a tiny ELRS receiver.

My bad, I thought this thread was about the new 2.4 board, not the 900mhz

Hi p-i,

No worries. I sometimes get confused. I still have a lot to digest, there is a lot I still don't know, and things are changing pretty rapidly.

Even though I am a retired software developer, I am reluctant to delve into the CLI scripting language...partly because I would likely need to learn the intricacies of the chipset. Anyway, I work to understand things that are "more on the surface".

Hello everyone. 

I am a huge fan of 3" 1S, and I picked up two of these boards. I just recently finished a 65mm build on one of them, and it has been a blast to fly. Most of my quads are R9 (slowly being converted to ELRS,) and I've never experienced such a locked rc link as I do with this board. 600mah 1S gives me plenty of time to fly midrange, and then freestyle for a few minutes upon return. The 200mW vtx has the smallest antenna I've seen, just a little stub of magnet wire, and it really performs impressively. I'm really pretty blown away by this board.

I picked up a couple of the new super tiny gps receivers by NLRC, and I plan to add one to this build. I've used soft serial before with great success, and am hoping for a similar experience with this build. What really helped me wrap my head around SS was a conversation I had with Flywoo support. I'll share the notes and images from that thread, and maybe it will help others too. After that experience, I really started to appreciate FCs that include an extra pad or two capable of acting as a serial uart, without requiring one to give up the LED pad. I really like having leds, for aesthetics, and espcecially for flying LOS. They can double the range in certain conditions.

Anyway, here's my little bug out over 1.3 miles. I think it was a 9ish minute flight, but I've sped up the video to 4x for you, because who has time for that? Well, actually, I do. I like longer videos, so there's also a or so maiden flight on my channel that breaks a mile with this same little quad if you're interested. (I rushed these videos up, so Volume WARNING!) Gram for gram, it's near the top for most fun I have flying, and 1S is so easy to maintain and prepare. The fun value is through the roof. Oh, and I lost video (80-100%) for about 20 seconds on the return flight in the video linked first. Concerned, but not panicked, I laid my trust in the unflinching rc link and kept the sticks steady and made it through. (sorry for the spoiler.) Hope this is informative, or at least entertaining. Cheers-

Hi Santiago,

Nice little quad.      Thanks for sharing and thanks for the videos.

You mentioned a thread where Flywoo helped you with SoftSerial...please post the link here.   Thanks.

iFly4rotorsHi Santiago,

Nice little quad.      Thanks for sharing and thanks for the videos.

You mentioned a thread where Flywoo helped you with SoftSerial...please post the link here.   Thanks.



(Disclaimer: I have a rough understanding of Softserial's underlying mechanisms, but a practical understanding for implementing it. Please correct me if I get anything wrong on the theory.)

As I mentioned, I'm back with the documentation on softserial that finally helped me make sense of it, and use it successfully. Softserial is incredibly useful when you are trying to get more out of F4 boards, with their limited uarts (2.) You can have full confidence in your equipment and the configuration too, because the idea is to move a non-mission critical function to the software emulated serial (Softerial,) port you create, in order to free up a full actual uart for the intended equipment, like a gps module. The limitation of Softserial as I understand it, is simply that it doesn't quite perform (some data being transmitted across it may be lost, likely due to the overhead added by emulation,) on the level of an actual hardware uart. So even though Softserial let's you designate certain pads (the pad/pin must have a timer,) to act as an additional (software emulated,) TX pad, you wouldn't want to put something like Fport on it, or GPS, because losing control (and telemetry in the case of Fport,) packets on your RC link is what's called a failsafe (ha,) and if you have GPS hooked up, there's a good chance it's not just for looks. Losing packets of GPS data during a GPS Rescue (or similar,) event could end badly.

Looking at the options, usually the best candidate for connecting to Softserial is vTX control (Smart Audio/Tramp.) We only use this feature when we are on the ground. It relies on a minimal stream of data to function (I believe,) and the result of lost is packets (I'd guess,) is that we need to enter again the joystick command that didn't seem to register, or perhaps theres a momentary glitch in the display of the OSD menu. This means the limitations of Softserial are inconsequential. Freeing up that prevously used TX pad now gives us a full uart to play with.

One last note, it was not the flywoo support case that helped me. When I looked it up, it was about Softserial, but I remembered that even though I follow their instructions, I never got it to work. However, looking at the email again yesterday, I noticed they had sent me one last reply which had a custom hex file attached! I didn't notice it at the time, and eventually gave up when things didn't work. Im now certain the hex file is the last piece of the puzzle, and is what I need to make the configuration in question finally work! So I'm very happy to have dredged up that old email thread.

So, the Softserial document I was thinking of, which did the trick for me, was actually an HGLRC blog post. It's well done, in step by step format. Here is the link to the blog post, and here it is in PDF format if you prefer that, and it's also attached to this post. It's discusses specific hardware, but the same configuration can be carried out on most/many other similar hardware (F4 boards.) I'll try to help if anyone has trouble following it. Now that I think about it, perhaps this could have been its own thread, but I'll leave that up to the mods at this point.

Many retailers have the 2.4GHz ELRS AIO in stock now. For some reason, RDQ is $8 cheaper than everywhere else:
https://www.racedayquads.com/collections...controller

Not sure what I'll use it for yet, but figured I'd jump on it now should they adjust their pricing.

It will be interesting to see whether HappyModel jumps on the NanoLongRange craze and releases a Crux 3 LR...
https://www.rcgroups.com/forums/showthre...st47278025

Well I've spent quite a bit of time digging into the 915 MHz AIO to try to find a way (fine pitch soldering assumed) to get both I2C and a UART for GPS hooked up so I can have a complete INAV setup. Although I've had great success with the 'F411 based Noxe V1, this particular AIO has things allocated in a way that makes it unlikely to support any external I2C devices. And that takes out my BARO and MAG. I can free up a UART by connecting the GPS to UART2, and perhaps that will provide crude RTH, but what I'd really like of course is for HappyModel or someone to make one of these much more INAV friendly.

Any idea if the 2.4GHz version is any better in that regards ?

To me, the CrazyF4-ELRS 5-in-1 might be a very good FC for small park fliers that don't need a GPS; both small whoops and open prop quads. After all, everything on a single board...all you need is a frame, motors, props, and a camera. 

I still would not consider it for mid-range to long range where a GPS is a MUST have component. 
Yeah, I wouldn't be hacking the FC just to try and make one work either.