Splash proof a USB connection?

[Nonsteeler]

I'd like to 'splash proof' this USB connection, see:



Background
Busch und Mueller's E-Werk (a dynamo charger) will not power my Gramin Edge 705 directly unless I put a mini-USB cable in between the e-werk and the garmin (apparently a problem since firmware 2.6). If I skip the mini USB cable, the GPS goes into 'PC-mode'.

I believe for small connections there are these condom like rubber stocking collar thingys, maybe soemthing simlar will work here, too? Or lots of bluetack?

[marcusjb]

Do you want it to be a permanent connection?

Self-amalgamating tape could be a good solution.

Heat shrink could work, but wouldn't be as waterproof - easier to take off though.

[Biggsy]

If there wasn't a rubber product on the market made especially for the purpose (?), I would just use a piece of self-amalgamating rubber tape, and re-do it everytime it needed to be unplugged and plugged in again.  You'd just have to rip off the tape.

[Nonsteeler]

Self-amalgamating tape? Never heard of that. But indeed it seems like a viable option. Just have ordered a role.

Do you want it to be a permanent connection?

Well, the e-werk can also power my phone (which sees no need to go into PC-mode but has a stupid non-standard charging plug, so again I would need the same adapter). But the phone is not an issue on a 600km audax. PBP is a different matter, however. Hence, ideally a non-permanent solution is preferable.

[Kim]

+1 for self-amalgamating tape.

If you're not familiar with it, it's non-sticky magic rubber stuff that looks superficially like insulating tape.  Stretch it to about double its natural length while liberally winding it round the joint you want to waterproof, and over a couple of days it'll form a solid rubbery mass that won't deteriorate with heat or age.  It's the standard way of waterproofing connections to aerials (which get left outside in all weathers for decades), so it should be up for the job.

It's a bit trickier if you want to be able to disconnect it regularly.  I suppose you could try to molish some sort of mating sheath arrangement using partially-shrunk heatshrink, but it won't be anywhere near as waterproof.

Sadly the Neutrik IP65-rated USB connectors don't come in an inline female version.

[Ian H]

It might be worthwhile rooting around in Maplins (trls near the Quay).

[Cunobelin]

IIRC There are two types of lead......

What is happening is that your system is picking up the data pins and thinking that data is incoming and switches to data mode.

The other option is a "charging" as opposed to a data cable, this has the data connecter disabled, thus charging only and not triggering the data mode.

[Kim]

A 'charging' device typically shorts the two data pins together to identify itself as a dumb power source, but this isn't implemented consistently by different manufacturers (Apple are notorious for doing their own thing in this regard).  The obvious alternative is to leave the data lines floating, which some devices will happily charge from, but others won't (because following the standard, they're waiting for a host controller to tell them how much power they can draw), or will only do so at a reduced current.  I can't remember which the Edge needs to not go into PC mode.

But it probably doesn't make a lot of difference, as the connector on the E-Werk looks proprietary.

[Biggsy]

Self-amalgamating tape is useful also for handlebar accessories and many other things - so is great to have anyway.  My favourite obscure use is to cushion Campag Ergo buttons.

I can imagine making something that would be splash resistant with heat-shrink tubing - but more of a problem might be moist air that would get through a small gap that there's bound to be left.

I wonder if there are any proper waterproof USB connectors on the market?  To use, either the exsting connectors would need to be cut off and the cable wired to the new connectors, or connected via adapters that would need waterproofing with self-am tape.

[border-rider]

You just need to be sure you don't spoff twitter all over it...

[Kim]

I wonder if there are any proper waterproof USB connectors on the market?  To use, either the exsting connectors would need to be cut off and the cable wired to the new connectors, or connected via adapters that would need waterproofing with self-am tape.

The Neutrik ones I mentioned above are reasonably water resistant and compatible with normal USB connectors, but the inline versions only come in A and B male variants.


   Neutrik - Data Connectors - USB


They're primarily intended for Pro AV applications, where the main concern is the connector getting bashed about and trodden on, rather than left out in the rain, so they're a bit too sturdy for this sort of thing.

Ideally, I'd ditch the USB connectors entirely and go with some more suitable connector where possible, but that's only okay up to the point where you have to plug it in to some existing piece of kit.

[Biggsy]

Ideally, I'd ditch the USB connectors entirely and go with some more suitable connector where possible, but that's only okay up to the point where you have to plug it in to some existing piece of kit.

I think that's a good idea and could be achevied with the help of homemade adapters (when it comes to plugging into existing kit), but I guess Nonsteeler won't want to go to that trouble if not already used to messing about with a soldering iron (?).

[Greenbank]

A 'charging' device typically shorts the two data pins together to identify itself as a dumb power source, but this isn't implemented consistently by different manufacturers (Apple are notorious for doing their own thing in this regard).  The obvious alternative is to leave the data lines floating, which some devices will happily charge from, but others won't (because following the standard, they're waiting for a host controller to tell them how much power they can draw), or will only do so at a reduced current.  I can't remember which the Edge needs to not go into PC mode.

But it probably doesn't make a lot of difference, as the connector on the E-Werk looks proprietary.

With a 'dumb' cable, what power can/does a device typically draw? Can it take up to 500mA or does it limit it to 100mA because it isn't able to negotiate a higher current draw?

[Priddy]

I had the same with my e-werk, the cable they provided that went straight from the e-werk to the GPS caused it to stay in 'PC plugged in' mode, but using, as I assume you are, the two cables connected, worked properly.

My solution to waterproofing it was to wrap the connectors in electrical tape, that seems to have kept the rain out through a few storms in Wales. (Now if only I can keep the rain from leaking into the screen)

[Nonsteeler]

Thanks for all your input. As suggested, I used self-amalgamating tape. Regarding the phone connection, I wait and see if this is really a problem. One solution would be to get another cable from e-werk to usb female and then use again the magic tape to bound the e-werk to usb female cable to the phone cable.

[Feline]

Personally I molished my USB cable so my Reecharge (similar to e-werk) can charge and power my Edge 705 and it works fine. I just slit the cable open, soldered together the 2 data cables (the white and green) inside then sealed it up again with self amalgamating tape. It saves using 2 cables.

[MattH]

With a 'dumb' cable, what power can/does a device typically draw? Can it take up to 500mA or does it limit it to 100mA because it isn't able to negotiate a higher current draw?

Everything you could want to know is in the spec, here.

Basically, if you connect the data pins together then you are telling the portable device that the charger can supply minimum 0.5A or 1.5A (max 5A) dependent upon if it is a charging downstream port or a dedicated charging port.

The current that the device is allowed to draw is limited by the voltage drop on the supply.

If you don't connect the data pins together, then it assumes it is connected to a computer and cannot assume that it has more than 100mA available (unless it negotiates a higher current). That's from the main USB spec, not the battery charging spec.

[Nonsteeler]

Personally I molished my USB cable so my Reecharge (similar to e-werk) can charge and power my Edge 705 and it works fine. I just slit the cable open, soldered together the 2 data cables (the white and green) inside then sealed it up again with self amalgamating tape. It saves using 2 cables.

Hmm, interesting. Can you elaborate a bit on how you did it? Or point me in a direction where I can find more information? Ideally, an instruction for someone who normally doesn't do no soldering...

[Feline]

Personally I molished my USB cable so my Reecharge (similar to e-werk) can charge and power my Edge 705 and it works fine. I just slit the cable open, soldered together the 2 data cables (the white and green) inside then sealed it up again with self amalgamating tape. It saves using 2 cables.

Hmm, interesting. Can you elaborate a bit on how you did it? Or point me in a direction where I can find more information? Ideally, an instruction for someone who normally doesn't do no soldering...

You really can't go far wrong so long as you are very careful what you cut on the way in. I am not a very good solderer at all but I managed. This is how I did it:

Inside the black rubber casing of the USB cable there is a layer of foil. I carefully made a slit about 2" long in the rubber along the length of the cable and then the foil, being really careful not to nick the insulation on the 4 wires inside. Open it up so you can get good access to the 4 wires. then using a craft knife, razor blade or tip of a stanley knife carefully shave some insulation off the white and the green wire next to each other. Then just heat up you soldering iron, hold the white and green wire together where they are stripped, touch the join with the iron to heat up the wires and add a bit of solder to the tip. Wiggle around slightly to spread the solder on the join well and then remove. Your bit of solder should look shiny silver and not grey if it is done properly. Then get a bit of self amalgamating tape and wrap the exposed bit of joined up green and white wire in it to insulate. Then wrap the wires back up in the foil outer and pull the rubber back over. Then just tightly wrap the join in amalgamating tape to seal it and you're done 

[Biggsy]

Is that with a Garmin cable?  You can't be sure standard colours have been used with any old cable.

Heatshrink tubing is more reliable and compact than self-am tape for cable joins.  It comes in many sizes; get a selection.  Slip on a bit that's slightly larger than the wire, then heat all round by hovering the side of your soldering iron over it.  It can be used for both inner wires and the overall cable.  Don't let your soldering iron contact it for long otherwise nasty fumes are given off.  Do it in a well ventilated space anyway.

[Feline]

Is that with a Garmin cable?  You can't be sure standard colours have been used with any old cable.

Heatshrink tubing is more reliable and compact than self-am tape for cable joins.  It comes in many sizes; get a selection.  Slip on a bit that's slightly larger than the wire, then heat all round by hovering the side of your soldering iron over it.  It can be used for both inner wires and the overall cable.  Don't let your soldering iron contact it for long otherwise nasty fumes are given off.  Do it in a well ventilated space anyway.

Standard USB 2 cables should all have this colour coding and the one supplied with the Garmin certainly does. I've taken apart / repaired a few USB cables recently and they have all been identical inside. I can't speak for any cables supplied with the e-werk though since I have yet to molish one of those!

The trouble with heat shrink tubing is you would have to cut the cable to get it on before you join it, the USB plugs are a bit big to get a suitably sized bit over. And if you join the data cables not cut them then you can't heat shrink them. That's why I used amalgamating. TBH I have found that these simple low voltage connections don't really need to be waterproof to work anyway, so water ingress won't be a disaster unless it keeps repeatedly happening and causes corrosion.

[Biggsy]

Fair point, you may not want to cut the whole cable, so then wouldn't get suitable heatshrink over the whole lot, but I would at least cut the inner wires that are going to be connected, and use heatshrink on these.

Another soldering tip: before soldering, with the iron hot, put a blob of solder on the iron then wipe off by dabbing on a damp sponge.  This cleans and "tins" the tip.  Dab the tip on the sponge before soldering each joint.