LED Lighting
I finally found some very bright and very warm white LED strips for ambient lighting. They have a color temperature of 2400K which appears to matches the color of the halogen desk lamp. All I had to do was ask for for that temperature since they are not specifically list.
Here are the same LED strips used for bench lighting where I glue up the Technicolor Pixels to make them more water resistent. There are four rows of strips, each in a separate 2 meter aluminum tray with diffuser. They are powered with a 24v/5A power brick
I was tired of not being able to find things in my cabinet, so I added LED lighting.
Here are the components I assembled for this project.
The LED strips (30/meter 2700K) are stuck to molding so they will be angled in the cabinet, rather than facing straight down or straight back. These are installed in the cabinet using double face tape.
At the bottom left are two magnetic reed switches used to detect when either cabinet door is open.
Bottom center is a mosfet switch with a primary 3-pin connector and two 2-pin connectors for the reed switches. This is to eliminate any amount of current from flowing through the reed switches and damaging them, and unlike a relay it is completely silent.
The barrel connector will come out the back of the cabinet for a 12v / 2amp power brick to plug into.
The 3-conductor cable harness on the right has six 2-pin connectors, one for the light strips above each shelf, and a 3-pin connector on one end that plugs into the mosfet switch. The barrel connector wire will be attached to the other end.
For me, LED lights powered by AC line voltage make my eyes hurt. The reason is that all AC powered LEDs have a 120hz flicker. This is a high enough frequency that it is not visible, but your eyes may still react to it causing eye strain. See LEDs: Fighting Flicker
Even so, I really wanted to switch to LED lighting to reduce power usage, and to reduce the heat and constantly having to replace halogen bulbs.
Switching to DC
Since LEDs powered by a regulated DC supply do not flicker, I decided that was the way to go. Unfortunately, there are not a lot of options in this regard. In the end I went with 12v track lighting.
It turns out that low voltage track lighting is actually powered by AC line voltage in the track and converted to low voltage by an adapter built into each fixture which provides low voltage AC. I did not investigate flicker with these types of adapters, but based on a lot of reviews they are not very reliable and I don't like the look of the large adapter box on the fixture either. No doubt the quality and performance of these adapters vary greatly from manufacturer to manufacturer.
In the end I went with Line voltage fixtures and replaced the bulb socket in the fixtures with a 12v bulb socket. I then powered the track with DC current from a single regulated 24v power supply.
There are at least three different track systems. I went with H-Track so I could use this very affordable PLT fixture:
PLT MT16 Halo Track Compatible 10050 Amazon
Line voltage fixtures on the left and low voltage bulb fixtures on the right.
Applying Power
Initially the supply was to also be 12v, but in testing the LED 12v bulbs some brands would start to dim with even a 1v drop, so instead I put 24volts in the track and installed a very small 12v buck converter in the base of each fixture. This had the added benefit of reducing the current in the track and feed wire to almost half. This also allows for up to a 10v drop without effecting the LEDs.
I did not add an additional heatsink to the buck convert so I have to limit the maximum size of the bulb to 10 watts.
I used these buck converters:
eBoot Mini MP1584EN DC-DC Buck Converters Amazon
All the track lighting is powered by a single 24v DC power supply which is plugged into a switched wall outlet.
MEAN WELL LRS-200-24 24V 8.8A Single Output Switching Power SupplyJameco
Line voltage fixture with parts on the left and replacement low voltage parts on the right.
Here is the re-assembled fixture.
Dimming
At first using buck converters had a down side in that it did not work with a dimmer on the power line. However, I have now worked around that by placing a MOSFET transistor on the output of the buck converter and connecting the gate to the unused line in the track. This line becomes the enable line for the LED. Connecting the enable line to ground turns on the LED. It can also be connected to a 24v common anode PWM dimmer.
Since the enable line requires so little current a dimmer with any current rating will work, but some do a better job than others. This is the dimmer I currently like the best:
Armacost Lighting 2-In-1 Led Dimmer Amazon
Armacost Lighting 2-In-1 Led Dimmer Home Depot
Choosing a Bulb
I tried a couple of different 12v LED bulbs. I found that I prefer spotlights over floodlights. I went with Hyperikon bulbs which draw 600ma at 12v or 350ma in the track.
Hyperikon had great tech support when I had questions.
Hyperikon MR16 LED 7-watt , 2700K (Warm White), CRI90, Dimmable Amazon
Hyperikon Company website
Other Parts
Also required for this project was the lighting track, track joiners, and power feed connectors. The track is available in 2 foot, 4 foot and 8 foot lengths. Note that I used the single circuit track. The dual circuit track works with the same fixtures but would allow adding a second enble/PWM line.
4 ft. White Track Single Circuit Halo Track AmazonLive End Feed White Single Circuit For Use with Halo Track Amazon
Straight Connector - Single Circuit - Compatible with Halo Track Amazon