Hi all,
I'm having some trouble working out how to go about my first electronics project after completing the SparkFun Inventors Kit.
I have some cheap solar-powered fairy lights that only last for an hour or so each evening before they seemingly run out of power. They're like this:
I would like to breath new life into them by removing the problematic solar panel and battery to just use the string of LEDs, powered via mains. I would also like the ability to control them via my Arduino so I can play with light sensors and remote controls. I was hoping to be able to power them directly from the Arduino, but I'm not sure whether this is a good approach (or even possible).
I pulled the main unit apart to discover 3 x 1.2V 600mAh AA Ni-MH batteries connected in series. On my multimeter they read at around 3.26V, which made think my Arduino would easily be able to power the lights, itself powered by a 5V 1A USB power supply.
I de-soldered the string of LEDs and measured the voltage that was previously being passed to the LEDs and found it around 6.2V, which is where the confusion started to set in. I started reading about boosters and step up convertors but it all started to get a bit too advanced for me at this stage. I decided to live life dangerously and tried the string of LEDs first on the 3.5V out on the Arduino, and then the 5V out, but neither was able to illuminate them. (I tried touching them back to their original PCB and they came on, so I haven't fried them).
I'd expected this would be a fairly simple project for me to get started with (after all it's just powering LEDs that were previously powered using AA batteries) but now I'm wondering whether I'm already out of my depth. It doesn't help that I don't have any specs on the string of LED lights other than what I can determine with my multimeter from the existing set up.
So my question to the community is whether it's feasible for me to power this string of LEDs directly from the Arduino? And if so, what approach should I be investigating?
Alternatively, I guess that I might need a separate power supply for the LEDs, but could still control them via the Arduino using transistors. Ideally this power supply would be able to power both the LEDs and the Arduino though, so that I only need one mains socket. My gut tells me this is probably the better approach, but it also seems a lot more complicated than I might be capable at this stage.
Any help or resources would be much appreciated!