REBUILD: lessons & learning to follow (PT2)

[Motopreserve]

Hey folks. If you were one of the people following my last thread, you will recall I crashed and burned the 'chopstick' quad after the cheap Hobby King Power Distro Board gave way and killed power to one of the ESCs. Since the other thread was getting quite long - and there MIGHT be some things that people can learn from these attempts at building a first quad, I figured I'd start a fresh thread...'lessons & learning' Part 2 here we come!

...Spin up the props...lift off...hover for a minute...smash bang! Just that easy. In the ensuing nightmare - the GPS and FC took a bad hit, breaking the GPS to pieces (see below) and something weird with the Multiwii FC starting happening. It would not pass 5v power correctly to the Rx, so I had to order a new one. Witespy's infamous delays kicked in, and it was 19 days before I had the new board in hand.





The new FC is Witespy's Black Edition Multiwii FC, with the magnetometer (compass) removed from the main board, and the one on the top of the GPS used instead to avoid interference. I had wished I had chosen this one when I first ordered my FC for this build, and so I guess we can look at this crash as fulfilling my dreams for an interference-free FC

I tore the entire quad apart, and decided to see if there were some places I could lose some weight. Of course, that was easier said than done. I drilled some holes, shaved some layers on the mill, and still only lost a few grams. I'll tell you what will really shed the weight... it's called build #2!!!

Stay tuned for developments...

 

[SoCal Blur]

Good stuff. I was fortunate because a friend steered me toward the Black Edition Pro 3.0 EZ (no compass) when I was trying to decide wich Multiwii to get. Now I know why, after seeing what happened to yours. J/K. I know that the compass had nothing to do with your unfortunate crash.

If you're going to do a second build, add a couple of motors and go HEX

 

[Motopreserve]

At this point I'm just working on getting this thing back in the air and successful. I need more practice time than I've had up until now - and then I can worry about build #2 .

My thought is that the next one will be a quad as well - but the FPV style. Should have more room available for more gear - and if symmetrical, handle well too.

I have flirted with the idea of a hex. But extra motors and props are just more to break at this point! . I'll build a heavy lifter at some point I'm sure...

 

[coreyperez]

~Subscribed~

Scott,

I've really enjoyed my Hex and am currently researching an Octo build. Coupled with the XAircraft SuperX, I'm just trying to decide which route I want to take. I'm hoping to finally get the KK & start learning about the Multi-wii (in the future), but currently have a big "review" planned that involves some very expensive dynamic balancing components. I just need to find time and such to get to it.

Corey

 

[Motopreserve]

Did you get that Vortex balancer???

 

[coreyperez]

Well... Why yes I did!

I've got 3 balancers I'm going to pit against each other in the review.

Corey

 

[Motopreserve]

Looking forward to that review. I saw the thread about that thing - and honestly, if it was in stock I may have bought it. .

It it seems like the "right" way to do it - if you're going to do it.

 

[Motopreserve]

I'm still waiting on a case for my FC. A guy on another group is doing some nice (and cheap!) 3D printed custom cases. Fortunately he owns a whitespy Black Edition - so mine should be perfect when it arrives. Hoping it will get here today.

While i wait, I'm working on buttoning up the Multiwii code and fabricating some parts that I need. Namely, a top "cage" for extra protection, and a mount for the cheap gimbal I got. I plan on doing many tests before finally mounting the gimbal - but man! It's tempting to get it going right away to see what type of footage I can get. But no need to destroy the thing before I get any good footage - so I'll wait.

Ive made some changes to the basic setup that I started with. Mainly a change to powering the RX and FC with a UBEC. This method of providing power to these units cones highly recommended - and after reading a review of the inexpensive Turnigy 3-in-1 model from HK, I pulled the trigger.



It it offers some great features for the money. It has a "fuel gauge" style LED meter, an external low voltage warning light, and dpt switches that can choose between 5v or 6v operating power, as well as 3.7v or 3.3v warning. All this in addition to the more solid power than is provided by the BEC onboard any ESC.

The he external low voltage light can be placed out on a boom for better sight lines...



I have the basic setup back together - but it will come apart for installation of the FC case and to neaten up the wiring. The small Bluetooth module can be seen in the front of the stack - which allows for field adjustments of PID settings, as well as initial calibrations of Mag and Acc.

 

[SoCal Blur]

I'm still waiting on a case for my FC. A guy on another group is doing some nice (and cheap!) 3D printed custom cases. Fortunately he owns a whitespy Black Edition - so mine should be perfect when it arrives. Hoping it will get here today.

Would it be possible to provide the contact info for the guy that builds the case for the Multiwii black edition? I've been wanting a case for mine. Also, can you share what he charges?

With regard to the UBEC, are you powering the FC and then letting it power the RX or are you powering each separately?

I really wish RTFQ would build a clear dome that fits over the GPS with Shield/multiwii stack. The one they currently offer only fits it without the shield.

 

[Motopreserve]

You can check out the thread for the 3D cases HERE. He charges $10 including shipping. $8 for the second one if you want another. You just need to tell him which header pin configuration you have.

The way I am using the UBEC is: UBEC hard wired to the PDB. It comes over and plugs into my RX (which I'm finally running S.Bus). The RX connects to S.Bus on the multiwii which carries 8 channels of signal, 5v power and ground all on a single servo. The connection on the RX can be any of the 7 open channels since the sbus servo cones off only channel 8.

I bought that dome from Paul assuming it would fit his gear. Foolish . I'm going to see about making something cooler than a CD case - but might have to use one if my contraption doesn't work or adds too much weight.

 

[SoCal Blur]

You can check out the thread for the 3D cases HERE. He charges $10 including shipping. $8 for the second one if you want another. You just need to tell him which header pin configuration you have.

The way I am using the UBEC is: UBEC hard wired to the PDB. It comes over and plugs into my RX (which I'm finally running S.Bus). The RX connects to S.Bus on the multiwii which carries 8 channels of signal, 5v power and ground all on a single servo. The connection on the RX can be any of the 7 open channels since the sbus servo cones off only channel 8.

I bought that dome from Paul assuming it would fit his gear. Foolish . I'm going to see about making something cooler than a CD case - but might have to use one if my contraption doesn't work or adds too much weight.

Thanks for the link.

Yeah, I almost bought the dome but then I noticed that in the pictures, it barely covers the LED ring and the LED ring's diameter is smaler than the corner to corner measurement of the GPS shield. I've been looking at disposable bowls like gladware, etc. but they are ugly, and not that sturdy.

I just looked at the cases. The look nice but now I'm wondering about the mounting standoffs for the GPS, etc. There doesn't seem to be any accomodation for them.

 

[Motopreserve]

I'm going to drill some extra holes on the top with the drill press to accommodate the GPS. I just need to feel secure after the crash I had - and knowing there are probably more to come.

Im thinking of it as a security "blankie" to quote my nephew

 

[SoCal Blur]

I'm going to drill some extra holes on the top with the drill press to accommodate the GPS. I just need to feel secure after the crash I had - and knowing there are probably more to come.

Im thinking of it as a security "blankie" to quote my nephew

I wasn't so concerned about the top as I am about the bottom. It looks like an open design. Do the mounting stand-offs still work or not on the bottom. I guess it's worth the $10 to find out.

 

[Motopreserve]

I thought he said it had holes on the bottom for the mounting. I just know there weren't any on top. Either way - same holes can be drilled on top and/or bottom, and I haven't seen any other options for these boards.

Of course USPS shows it out for delivery - but mail came and it's not here. I'm just about done with the USPS. They have messed up so many of my deliveries at this point that I can only scratch my head in bewilderment.

going to to have some photos soon of the mock-up of the top cage (just simple aluminum) and the GPS mount....

 

[SoCal Blur]

I thought he said it had holes on the bottom for the mounting. I just know there weren't any on top. Either way - same holes can be drilled on top and/or bottom, and I haven't seen any other options for these boards.

Of course USPS shows it out for delivery - but mail came and it's not here. I'm just about done with the USPS. They have messed up so many of my deliveries at this point that I can only scratch my head in bewilderment.

going to to have some photos soon of the mock-up of the top cage (just simple aluminum) and the GPS mount....

Good, looking forward to see what you have come up with.

 

[Motopreserve]

Roll Cage...

While it's not as fancy as some of the cool looking roll cages I have seen around the internet - I realized I needed to make SOMETHING that might prevent catastrophic damage like happened with my last crash. If I could hobble something together that would prevent me from having to wait another 19 days for a replacement FC, then who cares what it looks like for now...

Rough and simple - maybe that should be my motto with this quad. I used some aluminum sheet stock I had lying around the shop. Made some rough measurements, guesstimated on most of it (the quad was at home while I made this at the shop), and used the metal break to bend it to shape.



I had planned on using 2 pieces to make a cross pattern over the GPS/FC stack, but the area of the center plate that I have to work with doesn't have a tab on the back to screw it to. Tried just the one bar across, and it seems like it should protect it well enough (after doing a mock-crash on the floor). It also should act as a handle - since I found myself grabbing the quad by the GPS shield/hood in the past. My only concern is whether it will introduce interference for the GPS antenna. I should be able to check that quick - once I can finally get outside for some testing...

 

[jbrumberg]

Good luck Scott. I hope it does not create interference issues.

 

[SoCal Blur]

Perhaps making a third piece and putting them together like a triangle, leaving an open, triangular space in the middle to prevent interferance with the GPS. Rule of thumb, if its metal, it is going to have at least some effect on radio signals....gps included.

 

[Motopreserve]

I've got no room up there is the problem. I'll give it a shot as-is and see before taking drastic measures. The other option is to use this stuff I just got called shapelock. It's mold able plastic which hardens. Might be a nice alternative if I can manipulate the shape just right. I'm more comfortable working with metal - which doesn't help with these quad electronics.

In lighter news (as in "light it up!") I just plugged in the cheap RTF gimbal I had ordered from Witespy and it smoked for a second. Great smell!!! I checked it - plugged it back in. No smoke but I think it's fried. So I'll have to probably wait another 19 days for that...

But that forces me not to mess with the gimbal until I get some more test flights under my belt.... Everything happens for a reason, or so they tell me immediately before I start seeing red

 

[Motopreserve]

Turns out the good old...slow USPS finally got the package here.

There are definitely drilled holes in both the top and bottom for mounting and extending the GPS skyward. So not extra work for me. It seems pretty decently made - and although it's only 3D printing plastic - it will give me a bit of peace of mind...



The only drawback is that I don't think I'll be able to see the Multiwii LEDs with the case on. There are holes for them to show through - but with the GPS on top - it was already difficult to see which were flashing. I guess this serves as encouragement to NEVER learn what the damn lights meant anyway

EDIT: Couple issues with the case. The guy put the slot in for the SBUS connection - but not sideways (like all the Witespy boards I've seen), so I would still need to mod it. Also, the drilled holes he used I now realize will prevent me from using the hardware that I had planned on. I wanted to use the nylon standoffs with male threaded end off one side. I had worked up a decent rig using the hardware I had - and now it's either lose the case, or back to the drawing board (and most likely the hardware store!). Nothing's easy...

DOUBLE EDIT: Wow, I'm on a roll. So I've already opted NOT to use the case. Don't want to dissuade anyone from trying one for themselves - but there are already a couple things not perfect for my situation. I saw that the SBUS connection is a bit tight - but then realized that I had already had to shave the nylon spacer I was using to fit the servo lead onto it because the mounting hole is so close to the sbus header on the board. With the material that makes up the mount hole on the case - no way the servo was fitting in there.

Also I realized that what I was hoping for (this is on me - not the case maker) is that it would be slightly "rubbery." Just to offer a bit of cushion. But this plastic (ABS or the other 3D type - I can't tell the difference) is hard. I think the nylon standoff will offer slightly better vibe protection.

Moving on...