Article

Solar-Powered Night Light with Li-ion Backup

This night light has two power sources: a solar cell with a peak output voltage of about 6 V, and a Li-Ion cell with a voltage between 3.7 V and 4.2 V. Three (of four) electronic switches in a 74HC4066N (IC1) control the device operation. The battery charging rate as well as the intensity of the LEDs may be adjusted.

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Materials

130178-PCB.pdf

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

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PCB

Download Gerber file: 130178-1.zip

Extra info / Update

Note: Since the original publication of this project/article, some of the components, software elements, webpages and other elements might have been updated or changed.

Components

The BOM (Bill of Materials) is the technically exhaustive listing of parts and other hardware items used to produce the working and tested prototype of any Elektor Labs project. The BOM file contains deeper information than the Component List published for the same project in Elektor Magazine. If required the BOM gets updated directly by our lab engineers. As a reader, you can download the list here.
Want to learn more about our BOM list? Read the BOM list article for extra information.

Download the BOM list

Component list

COMPONENT LIST
Resistors
R1,R4,R5 = 100kOhm 1% 0.25W
R2 = 330Ohm 1% 0.25W
R3 = 62Ohm 1% 0.25W
R6 = 120Ohm 1% 0.25W
Semiconductors
D1,D2,D3 = 1N4148
D4 = 1N4731A zener diode (4.3V)
D5 = LED, 5mm, color of choice
D6 = LED, red, 5mm
IC1 = 74HC4066
Miscellaneous
S1 = toggle switch, Newark/Farnell # 1310879
PCB # 130178-1
Connectors marked SC6V and LI-ION 4.2V = PCB terminal block, lead pitch 5mm

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Discussion (0 comments)

F1Andy 3 years ago

Is there a risk that the 4 2V cell will be over stressed , as the charge supply is only coarsely shunt regulated to about 4.3V without regard to cell temperature or max cell voltage?

Interesting use of a chip, any reason not use appropriate FETs instead and allow 50mA LED?

A.

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