This solar garden/path light was found at Target for $3! Nothing special about path lights, and the low price is no surprise in our times but this item looks very interesting for home projects. Instead of the fancy curved “good looking” enclosures it’s a simple cube. Very easy to reuse this enclosure. Reuse the enclosure, rip out the guts and build something cool. Use the Led, Battery, and the stake part to mount and power your latest creation. These kinds of things inspire me. I am compelled to find something interesting to do with it.
More details after the jump… Share your ideas in the comments
The complete unit is show above. I’m not sure what the metal is, I’m fairly sure its not Aluminum. Brushed chrome plated steal is my guess. The clear part is plastic. The square tube is hollow and mounts to the clear plastic part with a single screw. It is very easy to remove all the parts, as shown below.
A larger view inside the top enclosure. A single battery, LED on a PCB. The bottom side of the PCB has one of those epoxy spot chips which provides all the control. On the top side, the LED, small cap, resistor and a resistor sized inductor (green, hidden by LED mount). A pair of wires (red/black) pass though the box top. The plastic inside part provides a spot to hold the battery. The bottom cover, mounts with four screws.
Remove the PCB, keep the LED and battery for other uses. The LED could be mounted on your project board. I don’t see much value in the PCB, maybe keep it to charge the battery if you can use the 1.2V as your supply.
Make a new bottom cover or RTV in the small holes that might allow water in. Its a good idea to have a way for air pressure to equalize but the electronics would not last long in the weather as this package is designed.
There is room inside for a PCB and a 9V battery. Maybe use an Ultracap to store charge from the solar panel. The solar panel gives about 3V in strong light, I have not tried it under the sun, its snowing here right now but I expect the voltage to be about 3V unloaded. This could be a problem for the typical hobby project.
Maybe the LED board could be used as a power supply, the inductor is there to pump up the voltage to the LED which will need about 2V to shine. I did a quick test and found that the circuit is pumping the 1.2V battery up to about 2.8V to drive the LED through a current limit resistor.
The LED drive might pump a good bit higher if the LED were replaced with a cap. My initial test with a 10uF cap did not work when I tried this. Seems I should have built up a charge so maybe I did something wrong. Anyone have an idea?
The best option might be to directly charge a cap, or Ultracap from the solar panel to about 3V. Boost this up to 5V with an efficient switcher or power the circuit directly.
Idea 1 – Data Recorder
My first project idea is to charge a cap till some voltage level is reached. When there is a full charge, power up a microcontroller to measure weather parameters like sunlight using the solar panel, temperature, and humidity. This data would be logged, say for the last 5 days. As part of the power up, The LED would flash out the stored data so that a photo-detector can be used to convert this to standard serial.
Idea 2 – Solar Flashlight
Add a switch to turn on/off the light at night. Let the light charge up outside and use it as a simple flashlight. The enclosure is small enough to hold in the palm so this might not be so bad. Too bad these things are not designed to last.
What would you do with one of these? I have more ideas then I can afford the time to write about. Now its your turn, comment.