Wiring Diagram:




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The DVR sub-system is powered by a separate 5 volt BEC and is removable which allows
it to be moved from one quad to another if necessary. 

The ViFly Camera Switcher control wired directly into the receiver signal which is SBUS.
The switcher is permanently set to Channel 7, which is AUX 3. This will require a new
model which I will set up just for the purpose of quads running this switcher.

If this is one of the JHEMCU aio’s that you said came with BF 4.3 installed, I suggest checking to see which release candidate was installed on it- and then checking the known bugs/issues for that release candidate to make sure none of them will effect you (ie: failsafe issues, inability to use gps return).

This might fall into the, “it’s broken and needs to be fixed” category rather than the, “if it’s not broke don’t fix it”.

Edit- I like JHEMCU gear, they work well- but I don’t understand why a manufacturer would pre install anything other than a stable BF release.

I don't know....iFlight did the same thing with the BEAST some time ago.
Yeah, I have a couple of those as well.

Ok, I unwrapped the iFlight M8Q-5883 GPS unit and here is my initial impression:

Overall, the unit appears to be solidly built and is essentially the same size as the
Matek M8Q-5883 unit and ships with connection wires with a plug for the GPS on
one end, pre-crimped connectors or each wire at the other end, and an empty
connector to house the pre-crimped wires. This method does provide a connector for
configuring the wires in any order of your choosing. What this connector will plug into, 
I have NO idea since none of my FC boards have such a mating connector for it, but 
a nice option anyway. To summarize, it looks like a pretty decent unit.

That said, the wires are a smaller gauge (thinner) than those that ship with the
Matek GPS. Also, there is NO orientation arrow...so, that is just a guess whether
you get it corrector or not. As far as I know, this only effects the compass, however,
if you need the compass then it might take a bit of experimentation to determine
the correct orientation.

Anyway, I have decided Not to use it on this build. Instead, I will be installing my
trusted Matek M8Q-5883 GPS unit since I need the compass, need it to work, and
don't want to take any extra time fiddling with it.

Moving on, I am soldering up BT 2.0 connectors. Unlike the male connectors, there
doesn't seem to be an option to buy the female connectors with wires connected;
they are just the connectors. In any case, the connectors need wires on them in 
order to actually use them. Most of these connectors will be wired with standard
Red (positive) and Black (negative) wires. However, I am wiring a few with BetaFPV's
color scheme of Blue (positive) and White (negative). In addition to being an alternate
color standard (at least in the BetaFPV world), it will be an identification method for
me to quickly identify a particular connector. 

From this point forward, I will use the following color marking on power wires that
will attach to a component with a connector:

1) Red will be Battery Voltage; VBAT+ and VCC.
2) Black will be the + 5 Volt rail.
3) Blue will be 9 or 10 volts (for the VTX).

Even though the norm is to solder all of the components directly to the FC or other
circuit board, I am a big fan of using connectors and have been  using connectors
for various components since the beginning of my FPV journey. I have particularly
been fond of using connectors on motors, the RX receiver, the VTX unit, and the 
GPS unit. 

Using a connector on the GPS allows powering it without connecting power to the
quad which also powers up that heat producing VTX. For me, powering the GPS
with an external battery for sat fix works very well. 

I have also come to appreciate a connector on the VTX as I can disconnect it when
working on the bench where I need to power the quad, but not the VTX. In the 
past, I have used a 4-pin connector on the VTX  and just disconnect the whole
thing for bench work. Now, I am separating the power leads from the data leads
(video and SmartAudio) in order to use a BT 2.0 connector on the power leads.

As I review the wiring diagram and begin soldering things up, I am pondering the
flexibility of using connectors on the GPS and VTX. When in the field, a connector on 
the VTX allows it to be disconnected. One could just leave the VTX disconnected, 
power up the quad with the main battery, wait for sat fix, then power up the VTX. 
Now, this actually makes more sense to me than powering the GPS with an 
external battery.   

Yeah, I think that is what I will do with this quad. 

Wire in one of these, and you can do that without having to unplug/plug the vtx.

https://www.racedayquads.com/products/re...gL5HvD_BwE

I've had great success with both the Matek and iFlight GPS modules too. I pretty much always have to experiment with compass orientation in the FC in my experiences, sometimes the arrows don't even align with the way they solder the mag chip on the board. On iNAV I just experiment with the combinations until the heading indication lines up with North. After a few times, you get a feel for which way you have to manipulate the orientation settings relative to how the FC is seeing north against reality.

Another way to power the compass is via a 4.5V pad, which normally gets fed from the USB connector. This way you can carry a small single cell USB power bank to energise the GPS/compass for fix before connecting BATT power. Although it does mean carrying more stuff to the field, a USB connector is made for many connection cycles, and is very robust soldered on the board. Your connector option saves having to do all that. I get worried with connectors on tiny diameter wiring and fat fingers...you don't want to rip out a wire in the field just as you're ready to take off...

Hi Lemony,
 
Thanks, Man. I will put one on my next RDQ order...
which might be very soon. 

 
Hi Roteron,
 
Yes, that is a good idea when a +4.5 or +5 volt pad is USB powered. 
These new JHEMCU boards do have a +4.5 volt pad which I will test
to see if it is USB powered. A few of my older boards say that the 
+5 volt pad next to the RC link pad set is USB powered. On the other
hand, I have used many boards in the past that did not have a +4.5
volt pad or any pad that I know of that is USB powered. I guess it all
depends on what you have. 
 
Although I will still use connectors, I will wire up the +4.5 pad to 
power both the XM+ receiver and the GPS. I will then have options
for powering the GPS.
 
Yeah, this build has quite the wiring harness. 
 
Thanks

Regarding the wiring:

In the past, I have pretty much just used connectors that come pre-assembled with
wires, however, the wire that they have is thin and has a tough plastic insulation. The
advantage has been that I didn't have to "fiddle" with wiring up connectors, crimping
the pins, and such. This has always worked, but these wires are a  bit "stiff", the
insulation is hard to remove and does not take heat very well. Plus, the 3 pin ones
have Red, Black, and Yellow wires...period...no options.  

So, I ordered one of those kits with unassembled connector housings and pre-crimped
silicone wires. This kit has both male and female housings and the wires have a male pin 
on one end and a female connector on the other. You choose what color wires you want
and push the connectors into the housing where they "lock" in. The advantages are
that I get silicone wire and I have color options. Being more flexible, I believe the silicone
wires to be less likely to break. I will still use the Red, Black, Yellow for the video subsystem, 
however, I use Red, Black, Green for the RC link. Plus, I can now use Yellow, Blue, Green, 
and white for the GPS. This helps to differentiate the wires for easier identification. 

I like it. 

(10-Apr-2022, 02:57 AM)roteron Wrote: Hey iFly, what FC do you think you’ll be using? Navigation and position hold? INAV?

Hi Roteron,

I will keep the Betaflight 4.3 that came on the FC board. I don't know that I will need
position hold and prefer not to delve into a different firmware right now.

This picture shows the FC all soldered up and most of the components are placed in position.
Notice the "collection" of wires at the left corner (the front) of the FC. There are a lot of 
EXTREMELY TINY solder pads just behind that DJI connector. What a Royal PITA. 




.

I have one more of these JHEMCU GH743 AIO boards {which will go in Rescue-1}.
We will see how these two builds go. Although I like the list of features and there are 
plenty of UARTS, the board only has a few pads that expose the 5 volt rail and they 
are VERY TINY. One would think that there would be at least one 5 volt rail exposure
with a decent size pad, but Noooooo. 

     This board is clearly intended for use with a digital package.

I was pulling my hair out trying to get in there to work with those tiny pads. By the way,
thin, 28 gauge, wire was used with almost no uninsulated tip; there just wasn't room 
between the pads nor between the pads and the connector legs. It was just too tight.

I will say, it would be near impossible to solder this puppy if it was installed on the frame.

TIP: 

1)  Only use the CAM and VTX pads.  

2)   Pull as much as you can from the DJI connector; 10V, GND, TX6, and RX6.
      Use the supplied plug, cut it in half, make connections onto the pigtails.

3)   Consider using an external +5V BEC for peripherals such as DVR, GPS, etc.
      I will be incorporating one on the next build with the other board.

Moving on...

Next thing is to test the electronics package, get the receiver bound, and mount this
mess into the frame.



        

Speaking of mounting the electronics package onto the frame...
I really like how the RoninUAV frames have a dual mount setup where a 16x16
or a 20x20 component can be mounted in the back. There frames are quite
flexible and have plenty of space. 

Notice that I raised the FC board to allow plenty of space below it for the extra wiring,
connectors, capacitor, etc. 

Looking good. I’m a fan of Ronin’s frames as well.

I’ve found it’s easier to use solder paste on those tiny little pinhead sized pads. Still a total PIA though.
https://smile.amazon.com/MG-Chemicals-Pn...492&sr=8-3

Hi Lemony,

Thanks for the tip. I will order one of those.

I have a flux pen which works well and I also use MG-Chemicals 8342 No Clean Flux Paste in a plastic jar.
The flux works great and I use the H*LL out of it which does help. Even so, those pads are EXTREMELY
TINY and Really, Really close together. So much so, that I will not use those pads again, except for the
few that I actually need which is mostly the CAM and VTX pads. I think that I can get everything else
from SOMEWHERE else. It is a bummer that they don't have some decent pads to expose the 5 volt
rail. 

I opted to NOT put the 5 volt BEC on this quad, but it will DEFINITELY go on the Rescue-1 build.
I will pull what 5 volt power that I need from the BEC. 

I will certainly re-think buying the JHEMCU GH743 AIO board again. 

I am doing some "dry" fitting. It is a bit "tight", but I will get it all in there. 



 

I hear you iFly re teensy pads and wires. 

I bought a stereo working microscope several years ago and its become one of the most used and most favoured tools on my bench! I've done  ALL my soldering with it ever since. You'd be impressed with how it turns all this into a trivial matter. I also use it to strip off the tiniest amount of insulation needed on the wires going to those tiny pads.
And for all the young'uns...its just a matter of time