I made a bigger version for the living room

A project log for Sunrise / Sunset Lantern

A lantern with candle flame LED that automatically switches on and off around sunset and sunrise.

Maarten JanssenMaarten Janssen 08/31/2020 at 07:230 Comments

The little LED lantern is now working for a few weeks in the hallway and giving great light effects during the evening. I decided to build a bigger version to put on a shelf in the living room.

For the bigger version a simple single candle LED would not be good enough, so I bought a flame simulating LED lamp. I was hoping that it would be using the same kind of construction as the one that Big Clive takes apart in one of his videos. Fortunately it did, though the flexible PCB with the LEDs was a bit smaller.

Even though these lights are made to fit into a regular lightbulb socket and run off of mains voltage when you tear them apart you see that there are two modules: a little regulator that steps the mains voltage down to 12v and a module with the controller and the LEDs. I didn't want to use the little regulator so from the light bulb I only use the LED module and the diffuser part where the LED module is pressed in to.

Running this light at 12v will produce a lot of light and I find it to be too bright. The LEDs will start to work around 5v and I find that at 9v the effect works very well. For my build I'm using a variable DC adaptor so I have some control over the brightness.

For the rest the modifications to the build are simple. The +12v of the LED module is connected directly to the power input. I used a 7805 voltage regulator to step down the voltage to 5v for the Arduino, clock and display. And I used a TIP31C to switch the light with the base connected to pin 7 of the Arduino and the collector connected to the negative side of the LED module.