Kids, at night don't fear - light is here!

My two kirds always become sad and start crying when the night is coming. They do not want to sleep in the dark and we have to turn on some light somewhere in our house. So far so good (or bad as I do not like to sleep when the light is somewhere on and I  need to close the door completely in our bedroom just to be able to sleep in the dark - as I like it). That's the reason why I decided to build a simple light with the two together. The end result is described below.

I tried three different versions of the night light:

1. A single SMD LED (a standard LED will also do) and one 3.3V battery and a nice image of a minion (which they love - at the moment)

2. Same as 1, but a switch attached to turn the light off

3. Same as 2, enhanced with a photoresistor, so if the switch is on but it's daytime, the light will be off, but when the night comes turn on automtically.

Version 1 is fine, one just needs a LED, a 3.3V battery and nice printout of something cool your kids like (plus something to fix this parts, I used one of my demo boards)...

I would recommend to solder the battery in the lower center, so the board will stay on it's own, you might also want to glue the battery so it does not fall off - but keep in mind then you need to build at least the version with the switch to be able to turn off the light. See below version two and three from behind. On the left image you see the switch on top and on the right image you find the photoresistor at the lower left.

As you can see above I was playing around a little bit how to fix the image to make it stand a bit better, here is room for improvement....

If you want to build version three you should use the wiring below (the battery does not destroy your LED, but you might add a resistor before LED1)... When you are done with the soldering calibrate the potentiometer so that the LED goes off (when you are sitting in a room with light on), then when you put your finger on the photoresistor the LED should go on again.

When it was done, the first words of my kids were: Daddy that's COOL!

And, let's be honest ... this is what a father wants to hear from his kids, right?