Homemade Flashlight

I took apart an old solar garden light because the battery was dead. I used the solar panel to make a solar annoying device. I used the driver board (which I did not take a photo of) to make a homemade flashlight. First, I coated it in hot glue so the wires wouldn't break off. The board had a resistor, an led, and a 4-lead component I could not identify, along with the wires. I used masking tape, aluminum foil, and then mounted it in a case. The case is part of the plastic from a battery backup for a piece of network equipment. I cut the section of plastic with my scroll saw. My flashlight works best with a D battery, but could work with other sizes if I modified the case. I tried "orange size" hearing aid batteries and it worked, but not for very long. It does not have a switch. You have to take the battery out to turn it off.