A night light from one AA battery that can be powered by a solar panel.
It can also be used as a flashlight during power outages if the LED is not masked by an opaque cover.
The NiMH 2500mah battery will last several months without the solar panel.
Note: Danger of Eye Damage From Visible Light Emitting Diodes
This model uses a simple Joule Thief, BC337 transistors, and I added the LDR and a 100 uF electrolytic capacitor. For indoor use, you can use up to a 3 volt solar panel, as indoor light will not deliver as much voltage as a solar panel would when used outdoors. The LED is a "super bright" 10 mm LED.
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| Solar Powered Indoor Night Light AA Joule Thief schematic by Dave Hamm |
Shown here without the solar panel.
Modified from "Solar Powered Garden Light" by Dick Cappels, (modified from mrpiggs). His arrangement does not use the LDR (Light Detecting Resistor), and used a center tapped transformer. The idea of their model was for outdoor use, and depended upon the solar panel to detect light.
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| Solar Powered Indoor Night Light AA Joule Thief on a breadboard |
I wanted an indoor night light, so I added the LDR to better detect darkness while indoors.
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| Solar Powered Indoor AA Night Light Circuit Board Layout |
Dick Cappels also used 2N4401 transistors, and had no capacitor.
Their model was modified from from a circuit design by Nick Baroni, of Willetton, Washington, and published on the siliconchip.com.au website. Dariusz Flaga in Poland, noted that the BC338 is a good fit for this application.
Reference:
Solar Powered Garden Light
http://cappels.org/dproj/ledpage/leddrv.htm#Solar_Powered_Garden_Light
Circuit design by Nick Baroni, of Willetton, Washingtonhttp://siliconchip.com.au
