One annoyance with cheap LED lights is the flicker they exhibit. This is caused by how they are setup to run off of AC voltage. To keep costs down, the voltage is only rectified, turning the AC voltage into a signal that runs between 0 and 170 volts 120 times a second. It's the 120 Hz that makes they LED lights flicker. It is usually only noticeable when you are moving.
There is a way to fix the flicker. One method I wrote about back in July of 2011. The LED rope light I was using had a bridge rectifier on the cord, but no filter capacitor. So I simply added one and eliminated the flicker. That works, but not all LED lights place a rectified in an easy to access location.
My solution involved a broken laptop power supply. While the supply didn't produce the DC voltage to run the laptop any longer the portion for rectifying and filtering the power was still functional. I knew this because my roommate asked me to look at the supply to see if I couldn't fix it. I had hoped there was a blown fuse, but that was not the case. In my searching, however, I probed supply with my oscilloscope and found it first converted the incoming AC to 170 VDC. That part of the power supply worked fine. My roommate was going to discarded the power supply, but I asked to have it.
I used a high-speed rotary tool (a.k.a. Dremel) to cut off most of the circuit board leaving only the rectifying portion. I soldered two wires on the large filter capacitor and used jumper to connect the wires to a string of LED lights. Sure enough I had flicker-free LED lights.
My next task was to make a permanent fixture to house the converter. I used an electrical box with an outlet, and a zip-tie to hold the circuit in place.
The laptop power supply is rated for 100 watts, so it should be able to handle a substantial number of LEDs. This is a very cheap way to eliminate flicker and I am pleased with the results.
This weekend I got this idea that I wanted to build a picture frame. I've had a router for a year now and I've thought of a lot of projects but haven't done too many. So it's time to get on that. I only have a basic set of router bits, but enough to get my project started.
Unable to wait for a design, I went right away to my favorite home improvement store and browsed for the items I knew I was going to need. I've looked at the various hardwoods before, but until now I didn't have a project that needed them. Now had an excuse and surveyed my options like a little kid in a candy store. I settled on a nice 1”x2”x8' strip of unfinished oak.
Once back home I fired up Sketchup and worked out what my frame profile should look like with the router bits I have available. I settled on a profile that required 3 bits.
This profile uses a 5/32” Roman Orgee, a 1/2” roundover, and a 3/8” rabbeting bit.
Here is a sketch of what the frame should look like when I finish. It is setup to take a 12”x18” print with 3” of mat. The picture is one I took the other day and I felt it turned out well enough to frame for this experiment. The color the frame is roughly what I expect after staining.
The first cut I did was with the Roman Orgee—the smallest bit. I did this by hand with the wood held down by some quick-release grips. Despite trying to go slow I put some burn marks into the wood, but the cut went alright. The next bit was too big to fit on my router, but Xiphos has an old router table sitting in the basement. I had already played with it a little to see if I couldn't get it working. There are some parts missing, but I thought I should have enough to start. One item that was missing was the locking screw for adjusting the height of the router bit. I compensated by jamming wood under the table to achive the desired height. The first cut on the table was the 1/2” roundover which turned out beautifully. The 3/8” rabbeting bit on the other hand made a mess. The cut was made, but the edge was rather sloppy. Next time I won't use that bit.
After the router was finished I was quite pleased with the results—it looked frame worthy. I gave it a quick sanding and called it a night.
The following day (Monday) after work I got ready for the next part of the project. Being a little nervous about making mitering the cuts needed to turn the wood into a frame I decided to take no chances. I fired up Sketchup again, drew the board, and the locations of all the cuts—I even included the width of the saw blade because I wanted to make sure my measurements were right before I began cutting. After marking everything out on my board, I verified several measurements with my drawing. Only when everything was perfect did I proceed.
Our mitering saw at the house has a general construction blade. Since this was a test I wasn't too concerned about the cleanness of the cut, but nonetheless I made each cut very slowly—oak isn't the cheap pine I usually slice through.
My cuts were all good and I had a functional rectangle when I laid out the pieces. Assembling the pieces, however, was something I found to be more difficult than I had anticipated. I ended up leaving the project for the evening until I could come up with how I wanted to achieve the next part.