Assembly of the trees has begun.
As you might recall from my previous post, I picked up some LED Christmas tree kits from AliExpress, with "some assembly required"...
So far I've only had enough time for one side of one tree. I assembled the base so I could prop up the tree half to be able to give it a quick test:
Unfortunately, it turns out that the green LEDs are MUCH brighter than the red and yellow ones.
There are 3 different resistor values being used for the different colours, but I wonder if the included LEDs were a different rating than the others, as no matter which resistor value I use for it, it's still too bright. For a $4 kit, it's quite possible that parts are swapped in with whatever is available cheaply.
I did follow a youtube example to make sure I got the resistors in the right place, but I should have tested this before assembly!
Here I did some tests to determine which resistor value would be best for each colour:
The kit comes with 3 values for the LEDs: 330 ohm, 1k, and 2k. So I tried a few ways to balance out the brightness.
Turns out the yellow is fine with 1k. The red seems correct with the 330 ohm resistor that was originally assigned to the green ones. But the 2k resistor in the kit is not enough for the green LEDs - I ended up bumping up to a 10k in the test above, and that looks much more balanced.
I'll probably just try to clip the two wrong resistors off the board, and surface solder the new ones in place there.
One thing that surprised me is that the 3 LED sets seem to depend on each other for the flashing effect - trying to test light just one string before the others were assembled didn't work.