It's time for my second instructable on the series of instructables I call Pimp My Balcony(PMB) which aims at improving my balcony in different ways.
First part can be seen here
This time I've scored an old Ikea floor lamp that, after some re-modding and hacking, would fit perfectly on my balcony for those late night balcony hangouts.
Step 1: Get the Lamp
So I found an Ikea floor lamp in the dumpster (man do I love to recycle) that seemed to be physically undamaged part from the missing bulb. And so I decided to loose the original bulb and replace it with a 1W led and drive it from a 5V USB port... and also while I'm at it, add a dimmer to it.
These modifications can be done on almost any kind of lamp. I just happened to find this one so that's the one I'm going to use.
Step 2: Take It Apart
First thing I did was to take it apart to see what I had to work with. There seemed to be lots of space for both a led and a heatsink behind the reflector so that was a good thing.
I got rid of the ceramic holder and sawed off those two spiky things sticking out to make some more room for my heatsink.
Step 3: Modify It
Now I needed to drill a hole big enough to fit my heatsink and two smaller ones for the wires to the led. For the heatsink I used a aluminium rod cut down to size that I soldered the led on to. And as for the led, it was a standard 1W led that can be bought dirt cheap in bulk from ebay, which is what I did. One can get 10pcs for less than 2 bucks... What a time to be alive :D
How did I solder the led to the heatsink?
Well this was a bit trickier than anticipated due to me not having a soldering iron that could heat up the heatsink... well it could but I'm quite inpatient as a person so what I did was to turn on a cooking plate, put some soldering paste between the led and heatsink and place it on the stove. The stove heats up the heatsink with ease so the difficult part is to cool it down without spilling all the melted solder. You'll notice the solder will turn into a water drop looking ball and that the led will float on top of it so any kind of tilting will end in you dropping the led or having solder on the kitchen counter. My tip here is to have a small bowl of water close to the stove and carefully lifting the whole heatsink into it with pliers.
Step 4: Creating a Dimmerswitch
For the dimmer switch I used a 555 timer since It's cheap and I had one laying around. And all I did was to hook it up according to the many 555 dimmer switch circuit available on the world wide web. I based mine on a schematic from http://www.555-timer-circuits.com/led-dimmer.html... but one of the diodes on that page is connected the wrong way.
Since I was going to make this pcb myself I decided to only use one layer for ease and also have thick traces and margins. The use of only one layer forced me to bridge wires to avoid crossing traces on the PCB. Only to wired bridges was needed in the end.
I've uploaded a pdf of the circuit board I used to fabricate my PCB
Step 5: Produce Your Pcb
I'm not going to go into details on how to etch your own pcb since this was the second pcb I've made in my life and therefore feel there are probably lots of people out there with better knowledge and more experience, better suited writing an instructable on the subject.
But the steps I took can be seen on the images which are: laser print on overhead paper, place copper under UV-light, dip in bath of Sodium hydroxide, etch and finally drill holes.
Step 6: Solder and Mount Everything
I found a dual AA battery holder that proved to be perfect as an enclosure for my pcb. Of course you can use whatever you have available.
I also found a potentiometer with a switch function scavenged from an old radio also found in the dumpster.
When it was time to seal everything I couldn't find my hot glue gun so I improvised with a tea candle and a piece of aluminium.
Step 7: Let There Be Light
Last thing I did to this was to find a usb male cable to connect the to the power and ground input of my dimmer and connect it to my lamp and try it out.
And lo and behold it works! It's quite bright and more than enough for a 4½ sqr meter balcony so I'm quite pleased with the results. And the added dimmer function is great for setting the perfect mood light when required.
The benefits of using usb connection apart from that I can take this light with me and power it up with my laptop is that I can now also drive this lamp with a ordinary USB power bank which I've added to my balcony and will do a full instructable on later.
Now go out and enjoy your balcony, even during night times :-)