555 light sensitive circuit.


 I needed a small light activated lamp and, since I did not particularly like any existing commercial products, I decided to make one myself.

 Light bulb is made by a series of three SMD LED I recovered from a discarded LED light bulb. Everything fits in an old discarded mobile phone charger case, the plug of which I really wanted to reuse. I have also designed, on Autodesk 123D, a translucent cover, which I have also 3D printed in PLA, a corn based plastic. Parts were finally glued together with a glue gun. Not the best option, although a quick one. You can see results in the pictures below. Power supply I chose a small 12V 100mA Chinese switching one that was about one Euro.

 My intent is also to reuse and recycle parts and materials which would otherwise go into the bin.



Next is the schematic. 555 IC is working as a Schmitt trigger and LDR is a photoresistor, which is at about 5 kOhm in daylight. If one decides to use a different LDR value, the 36k resistor has to change accordingly.

Double sided PCB (Printed Circuit Board).

Some of the PCBs I had made from my files. They are a 23mm side size square.

A couple of pictures of the light in the Italian electricity socket. You can see the 3D printed case.

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