How can I repair Featherweight GPS Tracker after hard landing?
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Given the surface mount components on the board, and the inverted installation, I don't think you want to try hot air reflow. I think you'll have to reflow each pad with a soldering iron. That's what I would do were I trying to repair it. But with that much shock, the point may be moot. There could be hidden damage inside the ublox module, and potential random component degradation or failure from being powered while a component was ripped off. So don't be surprised if it doesn't work, and if it works, it might not be reliable.
How about contacting the folks who made it (I believe they are on this forum) and see what they say?
Gerald
How about contacting the folks who made it (I believe they are on this forum) and see what they say?
Gerald
I had a similar problem. Emailed Adrian (owner of Featherweight) multiple times. His only response was to ask for pictures.
Finally sent the tracker to him to see if he could fix.
He totally blew me off!
This was 3 months ago.
Finally sent the tracker to him to see if he could fix.
He totally blew me off!
This was 3 months ago.
mikec
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I believe the SAM-M8Q module itself has broken in half. I think your best bet is to remove what's left from the PCB and try to put a new module on (I buy mine from Digikey), but no guarantees.
I've only ever reflowed these parts in an oven, not used hot air.
I've only ever reflowed these parts in an oven, not used hot air.
yeah I think the module is toast. I cleaned up the pads, put the chip back together, and powered it up while on a conference call for work. It connects and communicates i.e. i can see the battery voltage on the tracker change from the mobile app but the gps never connects to any satellites. I think i'll try and order another module and see if i can get it to work. How exactly do you reflow parts in an oven?
mikec
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You have to have electrical contact between the pads of the two parts of the module, you are not likely to get it just pushing them together if that's what you did.
Oven = reflow oven, like https://www.instructables.com/Reflow-Toaster-Oven/
But if you do this to a pre-populated board I'm not sure what's going to happen. Using hot air would allow you to localize the heating more.
You were right, I got some conductive epoxy off Amazon for $3 and glued it back on.
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Conductive epoxy, at least the good stuff with a high silver content ($$ for a little bit), is a bit brittle. And the resistance is certainly higher than a solder connection. Just giving you a heads-up. I doubt it is generally used for this sort of electrical contact, but I could be wrong. I've used it in mechanical connections where a much larger contact patch exists, and the epoxy is not the means of securing the contact. In other words, about like one would use conductive paste in related circumstances.
Gerald
Gerald
mikec
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I would have put a glob of regular epoxy in the middle to carry some of the load. You may be able to squeeze some in from the edges and that might help.
The conductive epoxy was only intended as a hack to maybe get you and operating, no guarantees that it will last.
I'm not sure how you are mounting this, I've found with my similar GPS stuff that wrapping it in bubble-wrap and putting it in loose inside a nose cone can survive a harder crash that more rigidly mounting on a sled of some sort. YMMV.
The conductive epoxy was only intended as a hack to maybe get you and operating, no guarantees that it will last.
I'm not sure how you are mounting this, I've found with my similar GPS stuff that wrapping it in bubble-wrap and putting it in loose inside a nose cone can survive a harder crash that more rigidly mounting on a sled of some sort. YMMV.
I have four FW tracker modules. Your experience has encouraged me to secure the modules on the PCB so that this doesn’t happen to me.
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yeah i think i'm going to get some clear heat shrink and use that to help hold the module together. It wasn't the connection of the gps module to the circuit board that broke it was the module itself, it basically split in half. I think there may have been something wrong with module to begin with and not a problem with the solder on the featherweight board.
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FYI, I know from experience that clear heat shrink isn't going to prevent your GPS module or the antenna from coming off. It will just split. We used to include a piece of it with the Eggfinder Mini, people thought it was to hold the GPS module on but it was actually there to protect the solder joints on the side of the PC board. We recommend epoxying the GPS antenna to the can, and after a few years of recommending that procedure we've actually put it into the assembly instructions.
The construction of the UBlox M8Q is a little different than most other GPS's with integrated antennas. Most of them have the GPS PCB topped with a metal "can", with the patch antenna glued onto the can with conductive tape; there's basically one solder joint in the middle of the antenna. The M8Q has the antenna reflow-soldered to the "bottom" of the GPS' PC board, the pads on the "top" get reflowed to that square-ringed PC board which is how you mount it to your device. In theory the M8Q should be more durable than those with a glued-on antenna, but all bets are off when you lawn-dart one from several thousand feet.
The construction of the UBlox M8Q is a little different than most other GPS's with integrated antennas. Most of them have the GPS PCB topped with a metal "can", with the patch antenna glued onto the can with conductive tape; there's basically one solder joint in the middle of the antenna. The M8Q has the antenna reflow-soldered to the "bottom" of the GPS' PC board, the pads on the "top" get reflowed to that square-ringed PC board which is how you mount it to your device. In theory the M8Q should be more durable than those with a glued-on antenna, but all bets are off when you lawn-dart one from several thousand feet.
"I had a similar problem. Emailed Adrian (owner of Featherweight) multiple times. His only response was to ask for pictures.
Finally sent the tracker to him to see if he could fix.
He totally blew me off!
This was 3 months ago."
I doubt that Adrian "builds these" himself and trying to rework an SMT board is a bear without specialized equipment. Plus your board itself might be dorked with a broken contact trace in the board also. Replace the module and it still might not work. I consider it a waste of time to try to salvage. Just move on.
Rocketry is like fishing. If you want to catch fish, you're going to lose lures on snags. You fly rockets and you're going to have CATOs and deployment failures eventually. Whacked electronics are part of the game.
I had a deployment altimeter I just bought and immediately ground tested it. I do this with every new component now. It had a glitch in one of the deployment channels. I phoned the maker, told him the testing procedure I used and that the unit was not flown. I sent it back and he fixed it and told me what component was defective.
That's the only time I'd explore fixing a board. Anything that has been subjected to severe forces that shears parts off the board can have unseen board defects and can be a crap shoot to fix.
I had an altimeter that was dorked in a hard landing. Replaced a capacitor and it ground tested fine blowing ematches in testing mode. I am a paranoid person about electronics so I used it as a backup deployment altimeter. Good thing I did as the primary controller fired the charges nominally. When I got the rocket back, the "fixed" deployment altimeter didn't blow any of the charges. Ground tested again and the charges blew. There was a "gremlin' in there I likely wasn't going to find. That device ended up on the junk pile. If I had flown the supposedly "fixed" altimeter by itself, it would have been a lawn dart. YMMV but I don't fly salvaged electronics from lawn darted rockets. Kurt Savegnago
Finally sent the tracker to him to see if he could fix.
He totally blew me off!
This was 3 months ago."
I doubt that Adrian "builds these" himself and trying to rework an SMT board is a bear without specialized equipment. Plus your board itself might be dorked with a broken contact trace in the board also. Replace the module and it still might not work. I consider it a waste of time to try to salvage. Just move on.
Rocketry is like fishing. If you want to catch fish, you're going to lose lures on snags. You fly rockets and you're going to have CATOs and deployment failures eventually. Whacked electronics are part of the game.
I had a deployment altimeter I just bought and immediately ground tested it. I do this with every new component now. It had a glitch in one of the deployment channels. I phoned the maker, told him the testing procedure I used and that the unit was not flown. I sent it back and he fixed it and told me what component was defective.
That's the only time I'd explore fixing a board. Anything that has been subjected to severe forces that shears parts off the board can have unseen board defects and can be a crap shoot to fix.
I had an altimeter that was dorked in a hard landing. Replaced a capacitor and it ground tested fine blowing ematches in testing mode. I am a paranoid person about electronics so I used it as a backup deployment altimeter. Good thing I did as the primary controller fired the charges nominally. When I got the rocket back, the "fixed" deployment altimeter didn't blow any of the charges. Ground tested again and the charges blew. There was a "gremlin' in there I likely wasn't going to find. That device ended up on the junk pile. If I had flown the supposedly "fixed" altimeter by itself, it would have been a lawn dart. YMMV but I don't fly salvaged electronics from lawn darted rockets. Kurt Savegnago
yes, yes they are haha! I don't think my epoxy job puts the module back to where it was before the crash strength-wise. Maybe some small zip ties? i just want something to share the load so that conductive epoxy isn't trying to hang on to everything by itself. I should have dropped some regular epoxy in the middle like others have said but it's too late for that.
I have 30 years of experience with SMT, and I can fix one of those with a regular iron. Everyone else, probably not, lol.
To fix anything like that, you need at least a thermocouple based temperature sensor, solder paste in a syringe, a heat gun, some desoldering braid,. (not a blowdryer, they won't go hot enough. Clean off all the old solder with a regular iron, by adding a bit of clean solder. and remove it all with the braid, so you have a clean silvery surface on both parts.
Then you put a tiny dot of solder on the pads, put the part in place, and gently heat the solder to about 350-400 degrees, just enough to melt the solder paste. Too much heat will kill the part. If you look up the chip's datasheet, it lists the maximum solder temp and duration. If you're going too long, stop, let it cool to room temp, and try again.
Wear an antistatic wristband while handling un-packaged electronic boards.
You have about 5 seconds at temperature to make the connections.
I stick things like that to the antistatic mat with double sided tape.
A stereo microscope and a good set of tweezers are also nice to have.
To fix anything like that, you need at least a thermocouple based temperature sensor, solder paste in a syringe, a heat gun, some desoldering braid,. (not a blowdryer, they won't go hot enough. Clean off all the old solder with a regular iron, by adding a bit of clean solder. and remove it all with the braid, so you have a clean silvery surface on both parts.
Then you put a tiny dot of solder on the pads, put the part in place, and gently heat the solder to about 350-400 degrees, just enough to melt the solder paste. Too much heat will kill the part. If you look up the chip's datasheet, it lists the maximum solder temp and duration. If you're going too long, stop, let it cool to room temp, and try again.
Wear an antistatic wristband while handling un-packaged electronic boards.
You have about 5 seconds at temperature to make the connections.
I stick things like that to the antistatic mat with double sided tape.
A stereo microscope and a good set of tweezers are also nice to have.
I got the same response when the switch broke on mine. And I have always had it mounted inside the 3d Mounted protectors.
Good product + poor customer service = low probability for long term success.
I support them, I bought a second one and I will be a Blue Raven customer when it comes out. I just wish I had gotten more then 4 flights with it before the switch broke off. I can still activate it by sticking a toothpick in the hole and friction sliding it or pulling the battery. More of a pain than anything.
I would urge you not to give up on Adrian. He’s a good guy with a full time job. I don’t mean that as an excuse.
I'm very sorry you had an experience that seemed like you were getting blown off. Something clearly went wrong and I'd like to find out what happened. Please try emailing me again or DM me with your email address so I can see where I went wrong.
For anyone having a hard time reaching me, I make mistakes and can forget to follow up, but it is never intentional. Anyone who hasn't heard from me within a few days, please keep trying and I'll do my best to make it right.
Unfortunately, that switch is relatively fragile. If you want to use an external switch, you can leave the small switch in the on position, or bypass the small switch entirely by soldering the + wire from your switch to the "+sw" plated through hole that's on the side of the board opposite from the screw terminals.
Email sent.
Dave I. / Tucson, AZ
When I was doing prototyping I would use an iron to put solder on the pads on both sides, then used lots of flux and a lot of hot air to reflow the solder to get the GPS module to float into place. MikeC is right that the module has a spacer that lets the receiver surface mount parts to fit under the antenna. I don't think there is anything special about that spacer, though. Glad the conductive epoxy and a new module worked. If it were me I'd just put a big fillet of epoxy around the perimeter.
If a rocket hits "hard", electronics are going to break. Period. Don't diddle with trying to fix'em as there might be some breaks in the board conductors. Sure one can put new components on the board but the traces might be defective.
Had an altimeter from a "crashed" rocket I replaced components on and in a "smart" fashion (sort of) flew it as a "backup" on a larger rocket with a known reliable deployment altimeter. It ground tested "fine" when I pushed the button on the computer program to ground fire ematches.
Whereas the primary deployment device worked nominally and perfectly with a good recovery on the flight. My "repaired" unit should have blown it's charges at the lower set altitudes "BUT DID NOT!!" Charges were intact on recovery on the supposedly repaired unit. Granted I did the repair myself and went over the board with a magnifier.
We've all seen it with 2 dual deployment deviced rockets. Primary blows apogee and main and then when lower, can see the puff blowing out of the main tube from the secondary backup main charge. Didn't see that on my flight. That altimeter went into the junk pile after that. I wasn't going to mess with it after that as I likely wouldn't be able to find the gremlin. Not worth losing a rocket over.
Yeah, one can diddle with trackers but if they fail in flight, might lose the rocket.
I had a tracker from a hard landing one time. Worked fine on the ground but when launched it died inflight. Period. Wasn't a battery problem either. Turned off/on and it came right back up. I flew it THREE times on lower powered motors so I could do a visual recovery and it stopped working EVERY time! Another gremlin I likely wouldn't be able to track down so it to went into the junk pile.
There comes a time when electronics "need" to be retired after they've had some hard hits. Kurt Savegnago
Had an altimeter from a "crashed" rocket I replaced components on and in a "smart" fashion (sort of) flew it as a "backup" on a larger rocket with a known reliable deployment altimeter. It ground tested "fine" when I pushed the button on the computer program to ground fire ematches.
Whereas the primary deployment device worked nominally and perfectly with a good recovery on the flight. My "repaired" unit should have blown it's charges at the lower set altitudes "BUT DID NOT!!" Charges were intact on recovery on the supposedly repaired unit. Granted I did the repair myself and went over the board with a magnifier.
We've all seen it with 2 dual deployment deviced rockets. Primary blows apogee and main and then when lower, can see the puff blowing out of the main tube from the secondary backup main charge. Didn't see that on my flight. That altimeter went into the junk pile after that. I wasn't going to mess with it after that as I likely wouldn't be able to find the gremlin. Not worth losing a rocket over.
Yeah, one can diddle with trackers but if they fail in flight, might lose the rocket.
I had a tracker from a hard landing one time. Worked fine on the ground but when launched it died inflight. Period. Wasn't a battery problem either. Turned off/on and it came right back up. I flew it THREE times on lower powered motors so I could do a visual recovery and it stopped working EVERY time! Another gremlin I likely wouldn't be able to track down so it to went into the junk pile.
There comes a time when electronics "need" to be retired after they've had some hard hits. Kurt Savegnago
I agree with you but worst case here is the tracker just doesn't track. It's not in control of ejection charges or things that may make the rocket unsafe. Also, as long as the tracker tracks to the ground, even if it breaks again, i'm ok because i can use the last reported GPS coordinates to at least get close enough to find it.
The tracker that has been dorked in a crash might track on the ground but not after being accelerated by a rocket thereafter.
I agree that a crashed combo GPS tracker/deployment altimeter should really be doubly doubted after a crash.
When I fly one of those devices, I make danged sure of continuity on the ematches (there are devices to test for that without popping them) and everything is connected up perfectly when I fly in a nominal situation. Haven't crashed a combo GPS tracker/deployment altimeter device yet. I wouldn't trust it if I did and would put it in the junk pile.
Yeah sure, I sometimes use an oversized drogue chute and if the main fails, the rocket doesn't hit "that hard" so I'll test and recycle the electronics. It's only the lawn darts I either throw out (as they're pulverized) , bury or put in a junk pile.
If a GPS tracker breaks when it hits the ground in a lawn dart, yeah that last known position can get the flier to the hole. I've seen that many times with other fliers rockets besides mine. Just start digging to get the motor casing out to reuse as it's usually reusable and see if one can get the lithium batteries out so's not to contaminate the farm field. I confess I left lithium batteries buried in a field as I couldn't get through the clay layer with a shovel. The heat was building up and I figured if anything would harden the clay even more and just closed the hole up. Got the motor casing and was happy with that. Any electronics are going to be wasted on a true lawn dart anyways and not salvageable.
Kurt
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I had a mid-flight CATO with another manufacturer's GPS which resulted in the GPS module becoming separated. I didn't have the tools, skills, or knowledge described by Grog6 to make the repair. A friend tried the repair, but it didn't work.
Since then I ALWAYS secure the GPS module to the rest of the device with clear heat shrink tubing. Bought a 3' long piece of 1" diameter clear heat shrink tube some years ago and still have plenty for new electronics. Sometimes I even use two layers. First saw this on a BRB unit. Not everyone does this, but it is becoming more common. Won't save your GPS from a lawn dart, but it might from a hard landing.
Since then I ALWAYS secure the GPS module to the rest of the device with clear heat shrink tubing. Bought a 3' long piece of 1" diameter clear heat shrink tube some years ago and still have plenty for new electronics. Sometimes I even use two layers. First saw this on a BRB unit. Not everyone does this, but it is becoming more common. Won't save your GPS from a lawn dart, but it might from a hard landing.
I’ve concluded that some business models allow for repairs while others it’s sufficient that the product quality is excellent and replacements are available when your module gets broken or destroyed. By comparison I was able to get my Altimeter3 (which I loved) repaired but could not replace it after another lawn dart accident smashed it to smithereens.
I’ve bought several Featherweights and I am totally a fan of the product.
I only wish that the audio tracking part of the iPhone app provided some of the features of the more expensive Multitronix “Kate” — like maximum velocity, alt-az and distance callouts on descent, and landing detection. But because this only requires an analysis of the streamed gps data, that these features will come and make the Featherweight even more of a killer product.
I’ve bought several Featherweights and I am totally a fan of the product.
I only wish that the audio tracking part of the iPhone app provided some of the features of the more expensive Multitronix “Kate” — like maximum velocity, alt-az and distance callouts on descent, and landing detection. But because this only requires an analysis of the streamed gps data, that these features will come and make the Featherweight even more of a killer product.
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