Hello guest, if you read this it means you are not registered. Click here to register in a few simple steps, you will enjoy all features of our Forum.
This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Triple-Treat (Quanum Trifecta) Truck
#31
Recovering from the Bad Idea (Using Headers)
I had originally thought I'd use the headers on the SPF3 EVO and be "happy".  After a lot of dry fit testing I wasn't.  So I got it naked again.  This was a pain in the backside.  

         

The board is a bit flux'y now but thats not really an issue.  

Hiding the Wiring
I really wanted a very "clean" look to my build, so by switching from using pin-headers and direct soldering to the flight control I have the ability to really hide the wiring.  As I have the board mounted on a small platform I have space below the board and due to the folding design theres set patches between the F/C bay and the PDB location in the frame.

         

As you can see the wiring is going below the board.  Each run measured out to allow movement and positioning but keep things hidden.

The Receiver
Another tiresome exercise.  I the end I'm using the standard location, but making the receiver lay as low as possible.  The header on the Receiver will allow me to lift the F/C and tilt forward for access to the underside for repairs without too much fuss.

     

I'll have to reverse the antenna wires so they come back towards the flight control and can be fed up away from the tail propeller. The receiver (Flysky IA6C) have battery monitoring telemetry built in so the wiring for that runs below the F/C to the PDB location.  The F/C has its own battery monitoring, and will run in parallel.  I had though to daisy chain the two but the connector on the receiver is not likely to last long if always being unplugged to lift the F/C.

Todays Progress:
Working quite slowly I'm still very happy with the progress.  I have the ESC, power and Receiver wiring complete.  The LED control line is in place as well.

               

As you can see I have used a braided jacket to neaten the wiring.  It only includes the wiring going to the F/C, the other pairs are ESC and the Battery voltage for the receiver.
Builds: Mini-Quad  -  Tricopter 
A Blog

[-] The following 4 users Like Aaron's post:
  • Jebera, Oscar, sloscotty, unseen
Reply
Login to remove this ad | Register Here
#32
Nice job! Very neat indeed and a testament to your skills with the soldering iron.

Most people end up with a ruined flight controller if they try to remove the pin headers.
Reply
#33
I did cheat a little, pulled the plastic guides off the headers and wound up 320C on the iron, some desolder braid and did it pin by pin. New iron (digital controlled yada yada) too so a great way to familiarise myself with it. New iron solders perfectly well at 275C (fine wire to board)
Builds: Mini-Quad  -  Tricopter 
A Blog

[-] The following 1 user Likes Aaron's post:
  • unseen
Reply
#34
That's not cheating, it's the only way to do it without damaging the PCB!

If I have to do this, I gently lever off the guides (after cutting the 90 degree pins so they are straight), remove each pin with some ceramic tweezers that don't steal the heat as you melt the solder and then clean up the holes with a solder sucker.
Reply
#35
It's a Frame Up!
There's thread on RCGroups () thats gone well past 200 pages with mixed commentary and reviews of the Trifecta kit.  Like a true nerd I read this, twice, I still embarked on this project.

It will not go down as my smartest move.

Seriously, while the kit is quite a reasonable design, so much needs minor tweaking and adjusting just so things work.  Take the tail pivot assembly.  

   
The parts sit over each each other, but some rough machining means that one "grinds" the other when in their proper position.  Thats fine except the shavings then move between the parts and end up jamming things.  Spalling I think is the correct term.  Anyway, after some time with a bit of emery paper, steel wool and persistence I cleaned everything up so they rotate freely.

         
So then you go and mount the servo only to find the leads exit on the wrong side of the corner.  So a notch has to be cut into the cover plate to allow the lead to turn around the end of the servo and travel up the tail.  The next thing is that when the servo is mounted the gear runs ever so slightly out of alignment needing a small relief notch in the tail plastic so the servo mounted gear doesn't bind on the tail plastic. 

Naturally if there was a washer to two, and a little more "thought" in the execution none of these things would happen.  But we are talking Quanum, aka HobbyKing so half-arsed is to be expected Smile


Pull Apart to Put Together!
I knew I'd be doing this a few times.  The FC has been released so that I can access the underside and tailor the length of the tail ESC wiring now that the boom is fitted. Likewise I have to attach the servo to the FC - although I don't know which output to use.  Thats not documented!  

Once I know what output to use for the servo I'll be able to consider powering up again and centring the servo.  Then adjusting the tail position to sit level or slightly tilted to compensate for the rotation.  

               

I've got the tail motor on (even though I still need to sort out spacers) so that I could work on the wiring for it and get the boom assembled into the frame.
The PDB bay is starting to look busy (I'll save pics of how thats working out for my next post), but the main body is fully screwed together now and it's time to make things more and more permanent.

Will have to pick up some more heat shrink for the ESCs and LEDs - ran out of everything in the correct size unless I want to use dual wall :/
Builds: Mini-Quad  -  Tricopter 
A Blog

[-] The following 2 users Like Aaron's post:
  • unseen, sloscotty
Reply
#36
Close the Pod Bay Doors Hal?
You know the moment when you're building something and finally it starts having things done up for the last time?

I'm getting there with this build.

The PDB in the Trifecta mounts in the lower part of the frame.  Normally you'd use a plain PDB but I decided to use a PDB with Current and Voltage sensing plus a 5v regulator to run the FC, Servo and LEDs.  It's actually design for APM boards but I won't tell the SP Racing F3 EVO if you won't.

         

In a way these pics are getting ahead of myself, but as per the FC I have soldered to the top side, this lets the majority of wiring for the arms bundle together and utilise the "larger" side of the slot in the main fuselage to exit.  The Battery input and 5v for LEDs are the exception due to how the board is laid out.

   

As you can see I've used braided wire shield (held in place with dual wall heat shrink) to protect the wires and keep them looking neat where they emerge from the fuselage and move to the arms.  As the arms fold this was always going to be a bit tricky to do neatly.

               

Back on the top side and I fixed down the FC after attached the Tail Servo to output 4 - I guess I will have to do some mapping or something in iNav.  I'm also assuming that once I power the board from the PDB that the power rail will come to life.  So far on USB the receiver is powering up.  

I guess this is the problem with building using a new to me FC, on a more unusual frame layout etc etc

Will need to do some work for a decent GPS mount point, sort out the receiver antennas and generally do more fabrication like the motor spacers.
Builds: Mini-Quad  -  Tricopter 
A Blog

[-] The following 1 user Likes Aaron's post:
  • sloscotty
Reply
#37
That's a nice, simple looking PDB! What's the current rating? (Just curious...)
Reply
#38
Your build is coming along really nicely. Thumbs Up

Careful with the APM PDB, the 5V will actually output 5.37V to be compatible with the power input circuitry on the APM flight controller, so check that whatever you'll be connecting to the PDB's 5V output will be happy with the higher voltage.

Also, watch out for the current sensor output. I can't see on the Hobbyking page for the PDB what the actual output voltage from this is, but you should be aware that the current sensor input on the APM flight controller can tolerate up to 5V and the output of the PDB's current sensor may be scaled to match. The current sensor input on the F3 Evo can only tolerate up to 3.3V, so there is a risk that you might blow up the Evo on your first punch out!
Reply
#39
(17-Apr-2017, 09:03 AM)sloscotty Wrote: That's a nice, simple looking PDB!  What's the current rating? (Just curious...)

60A according to Hobbyking. (See: https://hobbyking.com/en_us/micro-hkpilo...nting.html)
Reply
#40
The PDB feeds the "VIN" of the EVO which has a small amount of regulating ability for its 5V and 3.3v rails. So the minor difference is accounted for - and even then good quality 5v supplies are only +/-4% and I'd imagine the BEC on a ESC even less accurate Smile

On the current sensor output, I do recall reading that - but for the life of me can't remember the solution. Probably a good reminder Smile

The BEC on the PDB is rated for about 2A draw IIRC and has no trouble with the tail servo (yes I got that working).

In fact, I just can't get the damn LEDs to work, but asides from that and the motor spacers, ESC wiring and shrinking for the front motors it's "finished"...
Builds: Mini-Quad  -  Tricopter 
A Blog

Reply
#41
(17-Apr-2017, 12:48 PM)Aaron Wrote: In fact, I just can't get the damn LEDs to work, but asides from that and the motor spacers, ESC wiring and shrinking for the front motors it's "finished"...

The problem here is that the control output from the flight controller is a 3.3V signal, but the LEDs want the control signal to be in the range Vin * 0.7 and Vin * 0.3 for high and low respectively. With the higher voltage your BEC is supplying, this pushes the control signal outside the expected range.

The easiest way to solve the problem is to add an appropriately rated silicon diode (like a 1N4001) in series with the power to the LEDs which will drop 0.7 volts and should bring the difference into the correct range. It's close though - if the diode drops 0.7 volts and you're starting with 5.37, the high value would need to exceed 3.269V to be good. So if one diode doesn't fix it, two certainly will.
Reply
#42
Thanks for the tip Smile

I may have some Zener diodes kicking around from another project that are suitably rated. Won't be too hard to resolve then.

I put this down to all my previous experience being with APM gear which by and large has better documentation.

On the current sensor front - PIX and APM current sensors are based on 3.3v signals but the Voltage sensing is a 5v signal. Yeah, weird, but that's how it goes. At least that's the way I read their doco. Worse case? I fry something ?
Builds: Mini-Quad  -  Tricopter 
A Blog

Reply
#43
The voltage sensor isn't a problem as you won't be using it. If the current sensor does input more than 3.3V, you'll fry the A/D input on the Evo's MCU which will either just stop giving you a current reading or let the magic smoke out, depending on how it reacts to the overload.

I'm not sure a Zener is the right kind of diode to drop the voltage to your LEDs. You need a simple silicon rectifier diode with a large enough forward current rating.
Reply
#44
Zeners act as regular diodes when used in place of a standard silicon rectifier diode, albeit some do have a higher forward voltage drop. The ones I had handy in theory drop 1.2v - which works just fine. If I was inclined I'd do some measuring of the current drain of the Liantian LED boards and then calculate the current limiting resistor and actually use them as Zeners (they happen to be 3.3v 1w rated) but that ups my component count by one and requires thinking Smile

Anyway because I like to live dangerously I just temporarily slipped one in series with the positive for each LED board. Plugged in the battery and "voila" perfect. Let them run for a couple of minutes. No heat issue (I'm guessing there's about 70ma draw of each LED board) and based on a 1.2v drop that's like 200mW dissipation - around 1/5th of their rating.

Will mount inside the PDB bay to keep the arms neater.

---

On the current sensing front - frying part or all of the SP F3 would suck, but flippantly I'll say that the multiwii/cc3d based current and voltage sensing seems to make reference to using the same as the APM/Pix setups and well the worse that happens is I fry my (clone) board.

There's some aspects of this hobby where I'll happily say do as I say not do as I do - this being one of them - there are plenty of "known to work for CC3D type" current sensing PDBs out there and I should have grabbed one to be sure. My choice comes from not knowing if I was going for APM/Pix or the "other side"...
Builds: Mini-Quad  -  Tricopter 
A Blog

[-] The following 2 users Like Aaron's post:
  • unseen, sloscotty
Reply
#45
If they drop 1.2V, the Zeners you have do indeed sound like a better choice, especially if they're rated for 1A.

The WS2812B LEDs pull about 60mA each when outputting white light, so you're well within the limits of your 1A Zener.
Reply



Login to remove this ad | Register Here