A couple of days ago, I finally finished my first fixed LED project.
I like my government's decision to drastically reduce the size of Germany's armed forces.
Firstly, this reduces cost for the taxpayers, and secondly, a lot of sparingly used equipment from closed bases with awesome quality is now available on ebay.
This is where it all started. The reputable lamp factory SIS Germany offers a nice desk lamp for around €200.
I found the same type on Ebay for around €30, coming from old Bundeswehr inventory.
This lamp is made to last. All metal, a sturdy construction, a nice design and easy to work with. Everything is bolted together, no hidden clips, rivets or glue.
Orignially it came with 2 pityful 9W CFL lamps, but the head was stripped of those and their sockets quickly.
What this lamp is missing at it's head is a handle, and a switch, so I installed these first. I also changed the part that connects the head to the arm, as I did not need a sidewards swivel joint. The old part lies in the middle. Then I installed a 670mA LED driver with a range of 35-70V. It refused to work properly at first, until I found out that there is a hidden CFL ballast in the lamp arm. After disconnecting that ballast, the problems were gone.
The extruded head allows to slide in an aluminium sheet of 203x167x1.5mm, so I ordered some of them from a machine shop. Next I got some cheap LED strips from ebay with 120 Leds/m.
I put them on the aluminium sheet, and used a warm white one in every third position, as I did not want the light to be completely cool. I wired them 5s4p. This way, I have 5 groups connected in series, with each group consisting of 4 strips in parallel, each 200mm long. The result needs 58V and works well on 670mA.
I connected this to the driver, and assembled everything. It works like a champ! The output is so much better then the 100W incan I had before. Although I am a tint snob on flashlights, where I prefer neutral white, the tint on the cooler side works really well on this desk lamp. It looks futuristic and encourages activity and productivity. I could not be happier with this light, and considering I paid €30 for it, €15 for the driver and LEDs each and €10 for the switch and handle, it is an awesome bargain. I have 2 more in the basement waiting for LED installation.
Here are some more pictures:
Lamp head from behind. The handle is a type also used on a server rack.
Fixing on the desk.
The new lamp with the old one behind it.
Quite bright indeed.
The new illumination.
The old lamp.
LED strips I used:
(120 Leds/meter, "white" and "warm white")
For similar projects with a different number of LEDs or strips, I recommend a cheap 12V/5A laptop power supply instead of the one I used.