RCTimer ArduFlyer (APM2.5)

[MrBen]

hey nice solder job, a couple of possible dry joints there though 

[Dusty]

aww well, I've gone and buggered it all up

So I set up the APM2.5 as per the wiki, everything was going really well. installed latest arduplane firmware, wrote bixler params to the board, configured radio, assigned flight modes to my 3pos switch and installed a mediatek gps. Got a fix indoors (gps was next to the window) and my hopes were really high. on the table it worked as it should (i had unplugged one of the ESC bullet connectors to stop it from flying off the table in "auto" mode lol)

So I went out to the field, powered up and waited for the gps to get a fix (solid blue light on the mediatek) and after a few trimming flights (not much was needed actually, I've flown the Bix2 many times before and it's all trimmed out) I decided to test the stabilize mode. flicked the switch and nothing...

flew it far away and flicked the switch to RTH/RTL mode.... nothing

came in for a landing and checked the switches while it was on the ground.... nothing

but the apm2.5 is all powered up, GPS fixed (solid blue led), and it's obviously passing the radio signal "through" the board as the plane was flying as if it just wasn't there.
Only thing I can think of is that when doing the launches for the first few test flights in manual mode, I had a failed launch and my bixler 2 went nose into the ground fairly hard, not hard enough to do any damage to the plane, but I think the impact/shock could have damaged something inside the APM2.5

I've since removed the board from the aircraft and carried out a visual inspection... there's nothing I can see that is damaged or broken or snapped and when I connect to the PC in mission planner it seems to connect fine, until I go to the flight data tab and there's no activity, even in the config tab I cant do radio calibration and when I go to the flight modes screen it just sits there and says "initializing"

I posted all this over on the DIY Drones site, and Chris Anderson replied within an hour (which is awesome) giving me the bad news...

if if won't get past the "Initiliazing" it means that the sensors are failing the startup test. You can try reloading the code, but I suspect your board got damaged in that crash.

at least I've had practice soldering one, I have no fears about soldering a second one, and in total the two boards have only cost me the same as what an "original" APM2.5 would have cost, so I'm not too distraught about losing out on the cash.

[Hoversight]

You have highly suspect joints adjacent to INH1 and INH2, identifiable by their dull colour and there may be more in those that are shiny but not smooth.

A 60w iron is unsuitable for light PCB work. The excess heat can be bad for the board and cause cold solder joints. I'd second bigMouse's recommendation of a 15-25w Antex and thin 60/40 solder.

Make sure all surfaces to be joined are clean (isopropyl alcohol) and be sure to heat the parts to be jointed before applying the solder, solder shouldn't pool on the tip.

[Cupid Stunt]

Did you at any point test the stabilise and RTH modes on the ground (obvioulsy clamping the plane down) just to see if it tried to level itself or powered up the motor ?

To be honest without doing that I'd never have launched in the first place
I doubt that an impact not strong enough to smash the Bixler to pices would have damaged a soft mounted board (even direct onto the foam)

[Dusty]

Yes, literally 10 mins before leaving for the field I tested it in the garden. It did move the surfaces to correctly stabilise the bx2, as well as turned the motor(I had unplugged an esc connector) in both stab and rtl mode.

if anyone seriously thinks this board isn't buggered, or that I've done a poor job soldering it, feel free to send me £40 and ill send you this board

[Hoversight]

Recommend you scour the base for a tech that pusser spent weeks training to solder and have them check the board.

[Dusty]

Thanks hoversight, I honestly appreciate the suggestions... but the problem is not the soldering. It was all working fine until that crash. I think perhaps one of the sensor's has bust internally due to the impact, but I'll try some older firmwares first.

remember, this is an arduflyer... not a proper apm2.5 from 3DR/DIY Drones so component/build quality probably isn't as good as their board.

[Hoversight]

The problem absolutely can be the soldering as a cold solder joint can be intermittent and then a bump with the ground can put paid to that, thus working on the ground is entirely possible ahead of not working following a bump. The board may still be buggered elsewhere, but before you absolutely condemn it I would advise you to go over the dull joints I pointed out and any non-smooth joints pyramidal like joints with creases in them. and then if it still doesn't work you've got a little more practice in before attempting the next board.

Although it was decades ago, I was trained to solder and as far as I can tell from the photo you posted there are  candidate cold solder joints. My recommendation to find someone on base who has been trained is based on them needing to be trained due to the mission critical nature of the gear they maintain and their expert eye ought to pick up on anything that looks suspect which your photo's don't reveal and a fix could be just a beer away!

[Dusty]

Thanks hoversight, you are right, even if the board is buggered elsewhere, checking the soldering can't harm it.

the only reason I'm positive about the soldering is that IN1 and IN2 are merely input pins... This input from my uhf rx is being transmitted perfectly fine through the board and into the aileron and elevator servos, producing the same effect as if the apm wasn't there at all, so surely those solder points are fine.

even if they weren't fine, they're not connecting any sensors or other components to the board so wouldn't be the source of this problem

any other soldering of the crucial components was done at the factory

[Hoversight]

We have an expert in the family so I asked for a second opinion on the soldering. The response was "there appears to be poor solder joints IN1 area, JP2 Solder tails in the out area 2 Possible bridges in the PWR M & R area".

[Dusty]

thanks, Just taken a closer look at the PWR M&R area in the picture and you're right, there does look like a possible bridge... those pictures were taken before the crash, perhaps the bridge is supposed to be there and the crash "unbridged" it... I'll need to take a look at the board itself now... but it's in the garage across the road and its raining outside lol....

either way, they were soldered at the factory not by me, so if the bridge isn't supposed to be there... strange that it worked fine before the crash.

I'll do a full comparison between the before pics (above) and the board in its current state (good job I took those pictures eh? i was practising with macro mode on my camera lol)

Cheers for the insight, I'll take a look at it tomorrow

[Dusty]

It's official, one or more of the sensors the IMU is buggered. Ran some tests today in terminal, when testing imu, only the Y axis reacts to movement of the board, the x and z values should also change. The sensors do an initial self run/test on power up... They never get past this initialization and so prevent the board from arming.

Took a look at that bridged solder joint too and asked someone about it. It's where you would plug in the power plug and would only cause an issue if I were to be using the socket... But I'm not as I power the apm via bec on the output rail and jumper1 in position

Stoll, shoddy soldering by the factory.. you get what you pay for I guess.

New one ordered from rctimer with my Xmas money (i.e. my own present to myself)

[MrBen]

the phrase "buy cheap, buy twice" springs to mind they certainly dont sound very durable, a bit shocking really

[Dusty]

the phrase "buy cheap, buy twice" springs to mind they certainly dont sound very durable, a bit shocking really

I agree Ben, hopefully I wont crash the new one.... I'll have to reinstate the flaps for launches (had previously disabled them )

[Hazel1994]

Hi guys,

Just a little warning, heres a post I got from here http://diydrones.com/forum/topics/rctimer-rctimer-arduflyer-v2-5-kit-flight-controller?commentId=705844%3AComment%3A1068378&xg_source=msg_com_forum .

Just a warning for those considering the RCTimer APM 2.5 clone: for some reason they messed up the 32u2 firmware, and it doesn't come with the DFU bootloader (it just has some unknown version of ArduPPM flashed directly). So you won't be able to upgrade the firmware on that chip without using an ICSP programmer, which can destroy the board if used incorrectly (wrong fuses set).

I don't know how serious this is.