What about building a solar light that just works really well?
… and why not make it so that the lighting patterns mimic those of fireflies? And what about making sure that the lamp will last many years, not just one season?
This project is kind of a “Hello World” of electronics, since it does not involve much more than lighting a LED. But it is something I had meant to do for a long time: a proper solar-powered lamp which, unlike most of the cheap stuff you can buy in stores, will stay lit for the whole night, have a nice light color, will have configurable dark detection, protection against deep battery depletion, several lighting modes, in short be exactly the lamp I wanted. So… here it is!
Before going further, I should mention that there are other projects around, such as the “Kimono Lantern” by the Tokoy Hackerspace, which is a very nice design – and also a pretty special story as it was used extensively after the 2011 Japanese earthquake. But it does not match the specs I had in mind, so I decided to do another design from scratch.
On top of the specs mentioned in the intro, I also wanted the lamp to be powered by a single AA rechargeable battery and fit inside a standard jam jar. The final specs are therefore:
- Single AA battery power
- Round board, 6.5cm max board diameter
- Light modes: constant on, on 50%, flicker – “candle like”, strong flicker, and several blinking patterns
- Installable into any enclosure with little effort.
- Warm white color
- Configurable dark detection
- Stop the LED before the battery gets totally depleted
- Weatherproof: most of the cheap stuff you buy in stores fails after a few months because of humidity, we don’t want this!
Below are a few shots of the lamps installed in fairly standard jars of a type you can find in every supermarket in the world. Depending on the shape of the jar, you will get various light patterns:
Designing the Solar Lamp
I published a series of articles on this blog over several months as the project went along, which you can read below: lots of info on how I came up with the design, and how it turned out:
- Solar Light project: the design
- Solar light project: PCB design
- Solar Light project: putting it together. This article covers detailed performance measurements on the final design as well.
- Solar Lamp: v2.0 PCBs are there
Build one yourself!
Over the next few weeks, I will make it possible to order boards from this site directly, so that you can build one of those lamps yourself. It is a nice and easy SMD project, and I am very much looking forward to seeing what sort of enclosures people come up with!