Good ideas with bad execution, or good execution of what should be bad ideas - an analysis of inferior, off-beat or malfunctioning products, and how other people's failures can help us design better stuff.
Multi-Purpose Flashlight Sucks NiMH Cells
Products designed with a dual purpose usually don’t do any one thing particularly well – think sporks. Though that wasn’t exactly the case with this solar dual-purpose flashlight/bicycle light that a blogger who goes by the moniker le magicien purchased, he discovered it worked a whole lot better once he redesigned it:
“I bought a nice solar powered waterproof flashlight with an incandescent bulb on one side and 3 bright red blinking leds on the other. It uses 2 AA size rechargeable NiMH batteries (1.2V 600mAH) being recharged by the solar panel and also has a conventional battery holder for 2 more AA size cells in parallel with the rechargeable ones. Thus, if the conventional cells are low you may always recharge the other battery holder. Suggested uses for this torch are: bike, car and at home.
I like this torch a lot but… the incandescent bulb eats the NiMH cells pretty fast and the blinking leds… who needs them? So the idea was.. why do not replace the rear red leds with white ones? There’s only one problem – white leds do not work with less than 3.2 volts – therefore some kind of voltage booster was needed.”
Here are links to the circuit schematics used in the redesign, plus some great photos of the modification work!