Things started off with a failed motor after the last crash. Turned out a wire sheered off from flexing during a crash long ago & the other 2 wires were nearly broken off. No way to spot it without removing the heat shrink tubing. There's no flex tolerance in those $12 motors. This in addition to a minimum PWM setting that was too low after a firmware update may have been causing flips for a while.
Next, it was off to test a new GPS derived heading algorithm & a 25 year old flash. This was the EOS 5D's lightest configuration with a flash.
The 25 year old flash wasn't much dimmer than the modern $400 580EX II but took forever to recharge. The GPS derived heading seems better.
Now the results of the new algorithm. Commanded & detected heading should be as close as possible.
Except for a few transients, it actually seemed to do better.
Finally, for those of you who use laptops initially instead of rendering 3D models of home made groundstations & buying laptops later, it's time to hack the Targus.
Targus deliberately prevented hackers from splicing unusual connectors to their power supplies by requiring a logic circuit in their connectors to turn on the power supply. Your only recourse to use a custom connector is some diabolical soldering & Dean.
Comments
Yes – you only have to pull any instrument from the cockpit of a military plane and you will find loads of cables/cable connections that use crimps and/or screw fittings & lugs, but no solder.
The discussion really needs to take place with the connection/joint/terminal ( …. or whatever) defined, before it can be stated whether or not solder is specified.
Are you saying that crimping with proper tool can be milspec (no solder).
I would imagine so. Is a weather coating norm? like adhesive Heat Shrink?
Go on...
I will start adding a bit of hot glue or rubber cement inside heat shrink, ( I have some of the TRW solder sleves, but only for single 24 ga wires)
Jack, I have had the same failure, several times. I added an extra layer of heat shrink tube longer than first and going 1/4" past solder joint, I also secure wiring with twist ties, velcro and rubber bands.
Lucky I have not lost a connection in flight, helicopters have the most vibration, but it has happen on planes to,
I now give each wire a firm pull to see if it will break. This method has work for me..
I test ArduPilot Throttle functions with only 2 wire connected to motor, It will spin a little but slowly, after 3 seconds my cheap ESC stops sending pulses, Very safe for bench testing and I know if motor is getting a signal... ( I have 3mm bullet connector on all motors )
I don’t there’s an antenna spec for any mil antenna on which I haven’t spec’d adhesive lined tubing. Always - for any in-line joint (power & rf-coax) in radar, tracking and airborne antennas – no exception. It’s a must. Helps keep moisture out, and buys time.
It’s not commonly stocked in hobby shops (sadly - costs more than conventional tubing), but it is obtainable online – as other members have now pointed out in their postings above this.
The alternative option: solder up, then brush some rubberised contact type adhesive over the wires, with a model paint brush. Why rubberised type contact adhesive? Because it isn't brittle - brittle adhesives - like super glues - as great, but vibration breaks them down over time.
Allo the contact adhesive to surface dry, slip the conventionalheat shrink tubing over and heat. Job done.
I note regards John's posting and pictures above, in which he illustrates binding 2 wires by twisting them together - prior to soldering. Indeed, this is standard electrical engineering practise in many avionic and marine workshops - the problem with it against the background of circumstances highlighted in this thread, is that, the breakages we are talking about are breakages that tend to occur at that point where the actual solidfied solder terminates and the wire transitions back to stranded wire.
It’s at just this point where stress/fatigue often results in failure.
Where John's notes are valid, is that in the case of a poor/dry type solder, having looped/twisted the wires prior to soldering will ensure that if the solder joint breaks, the 2 wires stay will not seperate - so yes, as I like to say, a “good for purpose practise”, and as said earlier - standard practise in many marine & avionic workshops.
If the connectors Bart speaks of are like the ones I use, they are the cat's meow. There is no crimping, only tool is a heat gun.
Imagine a translucent piece of heat shrink with a ring of glue inside at either end and a ring of low-temp solder in the center. One wire is inserted into each end, bare conductors lying beside each other, and a heat gun is applied to it. The shrink tube begins to tighten, the solder melts into the wires, and the glue melts and is squeezed into and just out of the shrink tube. Remove heat gun. Wires soldered, shrink is tight, ends sealed with glue. BAM! Love those things.
Got a box of assorted sizes years ago. Any ID label on the box has long since dried up and fallen off. If I can come up with a name I'll post for ya.
Another approach that can work well if you have the space is to run the two wires side-by-side and butt-join them. With the shrink over both wires it moves the bending force away from the stress risers at the edge of the solder and the edge of the insulation (which is also where you tend to nick the conductors when stripping).
Here's a not very good illustration:
cribbed without permission from http://www.rcgroups.com/forums/showpost.php?p=4496262&postcount=94
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