If you are anything like us you are constantly looking for somewhere to plug in your phone charger, which often evolves pulling the sofa out the way and unplugging that table lamp on the side board. Wouldn't it be easier if you could just plug your phone into the table lamp? This project is based on a 12v LED table lamp and a 5V USB DC 7V-24V to 5V 3A Step Down Buck Converter module.

Step 1: You Will Need...

Depending on the table lamp you are going to use to house your charger f, your design will vary and thus the parts and equipment required will to. Below is a generic list based on what we used, it is not complete but should give you a pretty good idea.

Parts:

Low voltage table lamp (anything between 7-24v will work, we used a 12v one from B&Q).
5V USB DC 7V-24V to 5V 3A Step Down Buck Converter Module.
Snap-in Miniature Round Rocker Switch Black (to turn the light on and off).
Wire, we used speaker cable
Hot Melt Glue
Solder
(Optional) Sticky backed felt.
(Optional) Heat shrink tubing
(Optional) Larger AC adapter, without this you will not be able to charge and use your lamp at the same time, one capable of supplying 650mA and 3000mA is best with appropriate connector for your lamp.

Tools & Equipment:

Basic hand tools e.g. screwdrivers, wire cutters, craft knife, spanner, a hammer, pliers etc.
Something to cut the slot in the lamp base for the usb socket case with, most likely a Dremel.
A drill and drill bits for the hole for the lamp power switch, the biggest drill we had was only a 10mm a step drill would of made things a lot easier!
Small round and flat files,to tidy up your drilling & cutting.
Soldering iron.
Multimeter.
Hot Glue gun.

You will of course also need somewhere to work, best not make this on the dinning room table, not unless you want to be explaining the soldering iron burns!

Step 2: Lets See What We Have to Work With.

So the first thing to do is to find out how much space we have to work with. The base of our lamp was covered with a adhesive rubber cover which we trimmed off the reveal the inside of the base. On first glance there is not much space in there, most of it been taken up by a large weight, the only way this was going to fit inside was to remove the weight and cut some of it away.

To reduce the risk of damaging things we would suggest that you dismantle the lamp at this stage, starting with desoldering the wires from the socket and slowly working your way through.

Step 3: Time to Make Some Holes

Having figured out where everything was going to fit we now need to drill a hole to take the switch for the lamp. Start with a smallish drill, say 4mm and then open it out in stages to the size you need for your switch. Unfortunately we did not have a drill larger that 10mm so we open the hole up with a Dremel. A better solution would of been a step drill.

Next we need to cut a slot for the usb socket, we chain drilled a few holes linked them together with a burr in the Dremel. Finally we tidied every thing up with a file or two.

Step 4: And Make Some Bits Smaller...

At first we had intended to cut the weight to fit around the electronics but having tried cutting it with a fibre disc in the Dremel we decided to go with the more destructive option of hitting it with a hammer and using a couple of the resultant pieces, mainly as it would produce a lot less dust.

With that done we started to dry fit everything together only to find the threaded tube that carries the wires from the led lamp fitting and also clamped the weight in place was going to be in the way. Luckily as we know longer need to clamp the weight in place its a simply task to cut the tube down with a cut off disk.

Step 5: Things Get a Little Bit Hot

So now its just a simple matter of soldering wires directly from the socket to the USB buck converter making sure that the positive on the socket (in our case the centre pin) goes to the positive on the board etc. We opted to solder our wires to the board but you could use the screw terminals provided.

You will then need to take a wire from positive of the socket to switch and from the positive of the lamp to switch in our case the white wire. Then take connect the ground from the lamp to the ground of the socket.

We have provided a diagram but as you can tell its all pretty simple.

Finally for this stage its just a matter of using the hot melt glue to fix everything together.

Step 6: Finishing Touches

Once we had given the lamp base a quick wipe over with some multisurface cleaner and checked everything was fitted inside carefully it wad time to finish off the base of the lamp and to stop it possibly scratching whatever you stand it on we used some sticky backed felt but if you were careful you may be able to replaces the original base cover.

Step 7: The Moment of Truth

To start with we plugged in the original ac adapter that came with the lamp and flicked the switch and the lamp went on just as it should! We turned the switch off, and it went off. Feeling confident we tried the usb port to charge a phone and that worked too! We then tried turning on the lamp at the same time and as we feared the lamp went out. Luckily this was expected and its a simple fix, replace the adapter with a higher current model, the one that came with the lamp was just 150mA, we swapped it for a 2000mA adapter from a printer and everything worked both individually and at the same time.