Hey all!This is my first instructable and i am starting with a very simple one. It is a simple, easy to make potable dark activated light, powered by a 9v battery.
Step 1: Get the Materials Required
B1--------------9v battery(and clip)
Step 2: The Schematic
There are 2 circuit boards; the dark sensor board and the led board. Ne555 in the dark sensor functions in mono-stable mode. Once the resistance across ldr decreases when the light falling on it is blocked, the trigger pin receives a pulse and the light turns on. When there is light the resistance across ldr increases and the light is turned off, however it gets off after a few seconds till the 100uf capacitor gets discharged completely.
Step 3: Solder the Stuff
Carefully solder all the components and wires according to the schematic.
Step 4: Testing!
Connect the battery clip to the battery and turn off the lights of the room; the light should glow. If somehow it doesn't, check the wiring properly and also check if the battery is dead. Now point a lighted torch to the ldr, the light will turn off again.
After testing, place the two boards side to side on the two faces of the battery and put a rubber band around to keep them in place.
Step 5: Finish!
Now you have your small potable dark sensitive light ready. You can use them anywhere you like; for example you can put it inside your cupboard so whenever you open it the light turns on and you can see your things inside.
Feel free to comment.