This weekend I built an auto-retracting charging cable station.

This weekend I built an auto-retracting charging cable station.

The Final Product

This weekend I built a charging station. I like to have all chargers conveniently available in one place, but I don't like the tangled cord pasta that always results. So I built this thing from a nightstand I got off Craigslist.
It Works!

Cables smoothly pull out and retract automatically. The tension is just enough that they'll retract on their own, but not when attached to a device.

Four cables are redirected through a series of hooks, attached to a pulley weight, and redirected up to a cable stable where they rest.

The weight and cable stable attachment points are both spring-damped. The hooks are staggered to reduce interference between different cords, weights, and pulleys.


Here's all the hardware used for this:
-1 Anker power brick
-3 Anker micro USB cables
-1 Pebble charger (shoutout to /r/pebble)
-1 External battery charger for my LG G3
-1 Generic 2-prong extension cord
-1 Cable stable thing (holds the four cables to the table)
-8 S-hooks
-2 Screw-eyes
-4 Long screw hooks
-4 Extension springs
-4 Compression springs
-1 roll of 16-lb twine
-48×3/4" Aluminum tube
-36×1/2" Steel rod
-1 roll of white/black vinyl tape
-1 roll of generic hook-and-loop cable wraps
-1 roll of mounting tape
The Prototype

Before I show the process, first let's take a look at the prototype.
Prototype Back

The original was a mess, but a functional mess. Those weights are just various steel tools taped to a bunch of coins.
The Prototype in Action

This actually worked surprisingly well. The only problem was that the weights and cords would frequently get caught on each other. So naturally, I decided what this needs is a complicated system of weights, pulleys, and a series of tubes.

I made sketches and a shopping list and everything this time. Only one trip to the hardware store for me!
The Haul

Okay, so I had to go to two hardware stores to get it all, but it was still just one trip.

Before I start on the hardware, this thing desperately needs a paint job.

It's amazing what two coats of paint will do for an old, dingy-looking piece of furniture. Looks like new.
The Weights

Time for hardware. First up is the weights. I cut 4 12" lengths of aluminum tube and put two holes in one end of each.
Weight Bottoms

A two-ply strip of vinyl tape forms the base, which is then wrapped to the tube with more tape.

Each weight has a 9×1/2" of steel rod inside. The rod will later be cut to adjust the retraction force.
Bar in a Tube in a Pipe

The PVC pipe will contain the weights so they don't tangle and interfere.
Attachment Points

I put a loop of twine through the holes in each weight. Went with the highly-underrated Zeppelin Bend to join the twine.
PVC Pipes

I put two holes in the top of each pipe. An L-screw goes through the holes to hold a pulley and fasten the tube to the wood.
Attaching the PVC

I drilled 4 pilot holes in a row, 1" apart, and attached the PVC.
Lower Directionals

These screw-eyes will hold the directionals that redirect the twine from the bottom.

S-hooks and small pulleys for the bottom.
Cutting Cables

I cut the cable into 4 lengths, each one 5' long. Holy shit this is hard with just a Leatherman.
Cable Ends

each cable has a spring on the end so it doesn't get shocked when it stops retracting. The wide part is a cable wrap, which gets caught by the cable stable and slides into the spring, Below that is a wrap of vinyl tape to stop the cable wrap from sliding away.
We Have Power.

Stuck the power block on with mounting tape. Did the same for the cable stable.
Well, shit,

This is about where it all began to go pear-shaped. You may have noticed that a lot of what I've built did not end up in the finished piece. Well, that's because this design was way too complicated and unreliable.

I also realized the PVC was actually totally unnecessary with long, smooth tubular weights like the ones I made, and the steel cable wasn't nearly flexible enough for the smooth rolling motion I wanted.


Okay, the failure mode in this video actually has nothing to do with the design and is just because the cables aren't harnessed to the cable stable yet. But I promise, this design failed in lots of other ways. Mainly, there were too many redirections, too much friction, and too many places for pulleys to derail. The retraction was not smooth, and it just kept finding new ways to break.
Fuck It

We're going back to basics. Let's try something a little closer to the original prototype.
Pulley Surgery

I cut a piece out of one side of several pulleys so I could hook them directly to the charging cables. 3 pulleys ones for the microUSB, one medium pulley for the Pebble ribbon cable.
Final Weight Design

I attached the weight, spring, and pulleys together directly. No more complicated redirection mechanism.
Adjusting Weights

This new design cut out so much friction I had to take off about a quarter of the weight for the microUSB cables and almost all of the weight for the Pebble charger (that ribbon cable rolls mighty smooth).
Cable Stable

I used two screw-eyes to harness the cords to the cable stable. Before this they would pop out every once in a while. Of course the only knot to use here is the bowline, king of knots.
Wiring up the Side

Some cable wraps, some mounting tape, and attention to detail are all that went into this.
The Hooks

I screwed in one hook for each cable, and staggered them to reduce interference between weights and cords. Then I wrapped them up neatly because, well, I don't like messy cables (obviously).
Job's Done

I wonder now if the time I'll save by having this is anywhere near the time I spent on making it. Probably not. Still totally worth it.

Have a good one, Reddit. Thanks for reading

Source : SigmaEpsilonChi from Reddit