Hey everyone! I'm working on a diorama and I have these prewired 3V dollhouse lights that I want to power using a USB connection. Since USB outputs 5V, I'm not sure how to bridge that gap without messing things up. I can't connect a resistor directly to the LED because they're already in a plastic fitting. Any suggestions on how to make this work?
3 Answers
You can actually place the resistor at the power input end of the wire instead of directly with the LED. That’ll help limit the current effectively. I recommend using a 150 Ohm resistor for your LEDs, particularly if they’re yellow and meant for 3V. If these are white LEDs, you might need a lower resistor. Just make sure to test it out carefully!
A USB buck-boost converter could be your best bet. It can convert the 5V from USB to whatever voltage you need. I’m using a DAOKI one, and it works great! Look for one that has a potentiometer and a digital readout so you can adjust the brightness of your lights if necessary. You can find these on sites like Amazon, Temu, or even at local electronics stores.
You might want to look into using a 3.3V regulator like the 1117 type. Just hook it up to your USB power source, and it can take that 5V input down to 3.3V for your lights. There are also some affordable modules from Temu that already have this built in, which could make things easier for you!
Thanks for the tip! I’ll definitely look into that.
Sounds like a plan! I appreciate the guidance.