Looking to see if I have missed an obvious gotcha.
Built a replica of Mr Steele's older 5" quad (Apex, Kiss FCv2, KIss ESC4-1, Crossfire Nano RX) and it was a dream, worked perfectly this last year.
The radio was the trusty Taranis QX7, not done the com-speed mod yet but worked perfectly with the serial speed reduced.
All happy and dandy.
Bought the recently released 3" Apex frame and went Fettec FC, Fettec ESC.
The unit powers fine and the Fettect One-Wire works ok, all registered and set up and I can spin the motors in the Fettec ESC Configurator at will.
Here's the issue(s);
I bought a Crossfire Diversity RX as the Nano was pretty much out of stock most places.
Weight considerations means I needed the Nano from the 5" quad as I am right up to the wire on the weight (249g) of the 3" Apex.
1. Desoldered the Nano from the 5" quad and soldered it into the 3" quad. As suspected it kept the bind to the radio fine and I can see it in TBS Agent and the crossfire.lua, but in the Kiss configurator I cannot for the life of me get any response to any switch, also no data is getting through to the graphs when you wiggle the sticks. This is a new build so has not yet 'worked', but I kinda know what I'm doing(!) in the configurator, just cannot get it to this last stage.
Have I fried the Nano on desoldering?
Putting a multimeter either side of the solder joint shows continuity.
2. Went into the QX7 model list and copied the existing 'model'. Soldered the Diversity RX into the 5" quad. It bound fine, is found in TBS agent, found in the crossfire.lua script, but exactly the same issue, no data is getting into Kiss configurator when move the sticks. Is it possible I fried this too wiring it up, as that seems pretty bad luck given everything else I've soldered on both quads is fine.
The MicroTX and Nano RX when they worked in the 5" quad were firmware 3.72 and worked fine, then. The Diversity arrived as v3.72. Since mucking around as above with no joy, I updated all three items to v4.11 with the same result.
I have checked the 'models' on the QX7 and they both seem fine, being copies of each other.
The RXs are both powering on and detected, it's the data passthough that is not working.
Have I upset something by having two crossfire receivers bound to the QX7?
Everything was fine with just one quad, but by making the cardinal sin of two changes at once (moving the RX from the working old quad to the new one and then putting a new RX in the old quad) I have foxed myself as I don't know whether the issue lies with me, the radio setup or something I'm missing on both quads.
Having never used two quads with one radio, is it quite simply a case of once either is bound and linked with the QX7/CRSF-MicroTX then ~either~ of the 'models' created in the QX7 will magically work, especially as one was working previously and I just copied the model in the menu of is there something I am ignorant of in how to select which model in the model list against how Crossfire links the model to the quad?
My thoughts are to do the QX7 com-port speed mod this weekend as really I should just do it.
I also am thinking about sourcing two new Nano RX's in case I have somehow torched them with the desolder-resolder.
I think I have cracked the Diversity issue, apparently this model comes with the output signalling type set to PWM instead of CRSF. I need to get into the settings using the AgentLite app or crossfire luascript on the radio and adjust the outputs. Joshua Bardwell was the source here;
Two Nanos just arrived in the post, I will try the 3" at the weekend.
Thanks for sharing the troubleshooting. I recently dove into the deep end with ExpressLRS TX/RXes think I will write up a post here with the steps to get that setup/configured once I get my head above water (it'll happen one day just wait and see).
On my Fettec Kiss FC I was not getting 5v on the pad marked Unify 5v near the TX1/RX1. (Unify Nano VTX is on the TBS breakout board which then also supplied the FPV analogue camera and the Crossfire RX Nano).
I presume this pad must only go active when the unify is mounted directly to the Fettec FC, which is an option I was not using? I am not sure.
I wired the Crossfire RX Nano as a test using the 5v & GND normally suppling any fitted LEDs and it fired up, bound to the Taranis, updated and then worked ok.
However, no control input was getting to the FC or showing in the Kiss GUI.
Eventually I gave up on TX/RX1 and wired the Crossfire Nano RX to TX3/RX3 using a cable plugged into the socket on the side of the FC and then in the Kiss GUI clicked Advanced Serial Configuration and changed the CRSF from Serial 1 to Serial 3. Works fine.
I then tested the video connections with where they would be going to the TBS breakout board for the Unify Nano VTX, as well as where to source power as had made a calculation error in not accomodating the three zip ties and heatshrink required for the Steele version of the CRSF whip antenna. This meant the build would go over 250g, so I had no choice but to bin the plan to include the Impulse Voltage Regulator board that is a feature of the 5" version and which I'd also bought.
I worked out where all the power and wires would be going, then assembled on the table and powered on testing everything, once working I cut, shortened and twisted cables as suitable.
Note that I did not manage to get Pit Mode/VTX power on a switch working through the Fettec FC feature which offer this function, so I elected to connect the Unify Nano VTX directly to the Crossfire Nano RX and control it using the TBS Agent Lite app on the Taranis (this itself was a recent Joshua Bardwell feature (roughly May 2021) and works far, far better than the old Crossfire.lua script method. Note though that I needed to update the Taranis QX7 to a much later version of OpenTX in order for this to work, the default 2.2.1 did not support it.
(I have made myself a Smoke Stopper using Mr Bardwell's old video with an automotive light bulb, mines quite nice as I built it into a single large wall light switch and hot glued in an XT30 battery input cable on the side of the block and then cables out for both XT30 and XT60, so I can use a single XT30 battery to test drones whether they natively take XT30 or XT60.
Before even the smokestopper though, I set the multimeter to Continuity Beep mode and then touched the probes in the correct red/black orientation to the end of the XT30 on the drobe. There was a very very short beep which immediately faded (quarter second or less) which is correct for a drone with a capacitor onboard. Remember that getting a continuous beep means short circuit and so never plug a battery or will likely pop, maybe even despite a smoke stopper.)
Sidenote; The Fettec has no onboard OSD and the Fettec board was out of stock so I'd got an ImpulseRC OSD board as per the original Mr Steele 5" quad. Annoyingly the 3" Micro Apex is fractionally smaller (duh!) and this OSD board won't fit in the 'normal' place behind the camera, something that made the Steel 5" so damned good and minimised cable length for the video quality. I figured the ImpulseRC OSD board would however just fit diagonally behind the camera and in front of the stack. I nicked a bit of clear heatshrink to isolate it from the carbon frame and it sits there very happily.
Set up unit in Kiss GUI, very much as per the settings culled from Mr Steele's original Apex build, with a hugely grateful nod to DrainmanFPV for his Kiss setup and OpenTX config videos. Drainman's video on how to put a throttle cap on the dial of the Taranis allows me 50% cap when mucking about indoors and full fat when in the field, and Steeles two switch Idle Up safety feature is a godsend. Acro/Level is also on another switch for outdoor/indoor flying.
Unit came in at 250g exactly, so closely in fact that of the three batteries I have, one makes it 250g and the other two make it 251g.
I plan to source twelve replacement screws in aluminium instead of steel for the top and bottom of the standoffs which should make me 'legal' again and also shorten the XT30 cable by a inch. Even this required 2 screws per motor a-la Steele's 5", so I also broke out the Loctite Blue there.
All is well and flies like a dream.
At some point when I've a spare gram I will rig a cable from the GPS input and power pads of the front-mounted OSD board that pokes a socket up above the FPV camera. I will then be able to velcro my Matek GPS unit onto this drone if I fancy implementing RTH or just want to see which is faster in a straight line, the 3" or 5" as I've already wired a similar removable cable into the bigger drone.
3" Micro Apex Frame
Fettec Kiss FC
Fettec 4-1 35A ESC & 470uf 50V capacitor
TBS Crossfire Nano RX, linear whip antenna
TBS Unify Pro Nano VTX
Foxeer Falkor 2 Camera
6S GN3 530mAh batteries (it flies with the bigger 6S batteries just fine, I made a XT60-XT30 adapter)
Ethix Flat Rat motors
HQPro 8 blade 3" props