So on to something different.  I needed to build something else, but what.  So I have a Crazybee 3.1 with some pads still left on it (after some crap soldering problems some months back).  Can I put the FlyFish 1303.5 motors on to this frame, get ELRS to work and have a working VTX with OSD.  Challenge set.

Parts

JMT Eyas 100 2.5" Frame
Happymodel Crazybee V3.1 2-4S 12A AIO FC
FlyFishRC 1303.5 5500kv motors
Happymodel EP2 Receiver (ELRS)
Happymodel Diamond VTX
Caddx Ant Nano 4:3
RushFPV Cherry 2 RHCP u.fl
BetaFPV Micro Light Canopy
Azure 2540 or HQ 2.5x3.5x3 Props
3-4S Lipos

The Build

So this board has no T2/R2 pads left, so i have one UART available.  It turned out the LED pad was toast as well, which is what i was going to use for smartaudio.  So I researched.  I have a T1, R1 and IR1.  R1 is a bad place to solder, so IR1 it has to be.  So first thing lets sort out the pads/ports/resources.



So initially my resource lists looks this.


This board uses 4.2.11 and yes I could put 4.3.1 on it since I am no longer limited by the SPI FrSky Rx that doesn't work with 4.3.1, but I don't want to add in more possible problems, so lets do it on 4.2.11. Don't fix what isn't broken.

So initially i was going to set LED_STRIP as a softserial.  But then i soldered a wire on it and the pad came off. :/  Seems I screwed this board up big time last time.  So what to do now.  I decided on BEEPER, but that wouldn't work for some reason.  Then I remembered Oscar had mentioned about splitting the UART's in his softserial article, so I looked up that and thought why not ELRS on IR1 and smartaudio on T1 (as a softserial).  So lets remap.

First lets clear what we don't have or need.



Now lets make a softserial using SERIAL_TX 1.


So I then soldered everything up.

Next was ELRS.  As usual this was problematic.  Turned out I needed to update my platformio udev rules file.  I maybe didn't have the entry that covered Happymodel EP2.  Once I updated it everything started working.  I soldered it to an old 5A FC with a bricked gyro and then configured it in betaflight so i could use passthrough.  I then flashed it with ELRS 2.5 and setup bindphrase, wifi, inverted receiver, etc.  This will never be updated again beyond this. I then desoldered it from the 5A FC and soldered it to the Crazybee FC.  Then fired it up in Betaflight.  No connection to the radio initially, but after power cycling the FC, it started working.  My guess is your radio needs to be switched on before you power up.  If I power up the radio after the FC it won't connect.

So now I have a working FC, VTx (and Smartaudio) and ELRS Rx.  Next will be mounting it on the frame and soldering the motors to it.

So next day I started up again.  I decided to undo the soldering of motors.  Why am I struggling?  This FC has connectors on it.  So i snipped the plugs off a set of 1202.5 motors and soldered them to the 1303.5 motor wires.  Then wrapped them in electrical tape.



I then proceeded to mount the FC and motors on the frame.  No real problems while doing this.  I've done many builds like this and have a way i like to do things on these builds.



After that it was a matter of adding the VTx, canopy, camera and antenna.  The VTx is the Diamond, so fairly easy to do.  Did a test without camera to make sure it was working before I put the canopy on, all was ok.  Then took a spare Ant nano and screwed it to the canopy, then slid the Cherry down through one of the holes in the top.  Canopy was then put on the bolts and another test to make sure nothing had broken while doing this.  Next I put some nuts on the bolts and cable tied anything that needed to be tied.  Finally added the props and some prop bolts.  i think it looks quite nice and slightly different.  Reality is I tried to make it easy to find if I drop it.



Now for a bit of weighing.

Dry



With CNHL 4S 450mAh



With CNHL 3S 650mAh



So i took it out for a couple of test flights.  This was when I discovered a problem.  Somehow the config on Betaflight had got borked.  I was locked in Angle mode and couldn't disengage it.  Apart from that it did fly.  I think I must have loaded in a dump at some point, but don't remember doing it.  So I had ELRS working, beeper worked and it obviously armed/disarmed, but flight modes weren't working.  Also the OSD was wrong and the VTx was setup wrong.



So today i did some work on the config and decided to try upgrading to BF 4.3.2 so i could get some of the ELRS settings to work. It is now setup correctly and hovers ok. I will take it out in the next couple of days and get some freestyle rips on it.

Nice, guess it is an old AIO? Not sure from the photo, but if there is still gunk on the board you may want to scrub off with some alcohol. Sometimes AIOs do fine caked in gunk, but other times just the tiny piece of debris is enough to wreak havoc. No more fireballs

It's the same one I used on the Flea 3.0 build. It's always been twitchy on FrSky D8. The other one flew on a single antenna for six months and never missed a beat, this one flies 25m away and failsafes.

I did try and do this a while back, but my soldering level was still too low, hence why it looks kind of bad in the picture. I need to try and find some isopropyl alcohol and scrub the board a bit. The stuff I have at the minute is only 70% (hand wash from Covid times). Also there's a ton of flux on it. I wasn't taking any chances when i soldered it up earlier so i let rip with the flux. I might have a go with the 70% stuff if needs be and put it on a window outside, it's pretty warm here at the minute so will probably dry pretty quickly.

Tomorrow I will solder the motor wires. Beyond that it's all plug and play. I built the frame earlier and mounted the FC on it, but need to do a big battery strap since the 4S 450's are as big as the 3S 650's. Probably going to try it on both of those. But it's primarily a 4S build.

I'm glad to learn the remapping stuff. I always wanted to do it, but never had a good reason to do so. Not to mention that EP2 that has sat in the parts box for two years. Yes it's a ceramic antenna, but i'm unlikely to fly this more than a couple hundred metres. Going to try and mount it in some way so the antenna is on the outside of the canopy, but I don't think it will have an issue if I fly inside 500m. I forgot to put a camera on the parts list, but it will be my favourite, the Ant Nano since that's all I have.

Hoping to get it in the air by Friday, weather is currently holding, but the possibility of rain is increasing daily i think. Would be cool to get out and fly for a couple of hours.

Updated the first post with the rest of the build.

Glad you got it in the air. It looks like it has some shakes and wobbles? The motors and props are new? If your VTX is stacked directly on top of the AIO (gummy to gummy), sometimes I found adding a nut between the two helps secured down the AIO a little better (sometimes not), but it seems something is loose or shaking?

Haha, the shaking thing was my hands. Add to that, stuck in Angle mode, which i hate flying in now that I fly Acro 99% of the time. Yeah it didn't look pretty. I abandoned it after the second pack.

The whole thing is down tight, but not too tight. The FC isn't resting on the connectors, it's all gummied and yes I have a nylon nut between the FC and VTX. The bottom nyloc nut didn't leave a lot of room on the top for securing the canopy, unfortunately.

Question for anyone who knows. I like running 3S and 4S on this. On 3S it hovers around 30% throttle and on 4S around 20% throttle. I want to set a midpoint and flatten the curve around those two (because i've never done it and just to see if it really makes it any easier to fly). Would it be best to set the midpoint to 25% and add a load of expo to flatten it so the stick/throttle response between 20% and 30% is a bit more slower/linear? I don't have any spare buttons right now to assign two separate rateprofiles to and honestly would prefer it if you could link the rateprofile to the profile, which i think was standard behaviour back in the BF 3.x times.

So I took it out again to fly some more and this time the camera crapped out. I'm wondering if my builds are jinxed. The first one had a borked config, this one the camera broke.

It looks like it is going out of focus. Is the lens screwed in tight, or maybe the lens housing has come loose from the board?

I thought that, but on the flight before that, it went blurry, then went crystal clear for about a minute, then blurred a little, then back to clear and was fine until I landed. If the lens was loose, I would expect it to go blurry and stay blurry. I did try and grip the lens and it seemed to be on tight.

So I looked at it and when i plugged in a Lipo it was crystal clear. The lens wasn't tight, but I have made it tight. The other possibility is the pcb for the camera was pushed against a cable tie I used to hold some wires back. Maybe that was causing the issue. Going to try flying tomorrow, but somewhere nearer. if it works fine, then I have no ideas. If it flies for a couple of packs and craps out, then i will replace the camera.

Pack 3 with the temporary blurring.