It is getting dark at 5:00 pm, and I have a bike shop signs that needs to be lighted at night during the winter holiday shopping season. So I repositioned a solar garden light ($5) in an Altoids box, cut off and took some pieces from some battery-operated IKEA Glansa LED Christmas lights ($1.98), and made some solar LED Christmas lights that don't require a wall outlet for their power. It was less expensive to modify stuff that had already been manufactured than to start from scratch.
When it is dark, the photo sensor in the solar panel of the solar LED Christmas lights tells the circuit to use stored battery power to turn on the lights. When the sun is shining brightly, the sensor tells the circuit to not turn on the lights, but rather to take the electricity made by the solar panel and store it to a rechargeable battery, so the battery has the powers to run the lights during darkness.
I am sure that others will be able to enhance this design. But for now, I can concentrate on building two sets of Chris King BMX and road bike wheels and avoid dealing with plugs, ladders, hooks, wires, and holiday electrical fires.
The next thing is to make solar window lighting for the Wheelgirl large, store-front windows. You can always make some solar LED Christmas lights to joy up an ugly window in your home. Jump for the instructions and more photos.
Photos taken by Wheelgirl. (The little lights around the Wheelgirl sign are two short strings of solar LED Christmas lights.)
I am not an electrical engineer. I am a beginning electronics hobbyist who is happily learning from reading and doing some of the projects under the online sweet and complete direction of the ladyada.net site. (Check out my post on the Minty Boost USB portable battery pack project.)
For this solar LED Christmas light project, I changed out the original rechargeable battery for a stronger rechargeable battery. (I am still experimenting with rechargeable batteries and solar panel recharging times.) I also chose the IKEA Glansa LED lights because they look truly horrible in the daylight. They are tiny and weak. Perfect for this project, since they are inexpensive LEDs, and they draw very little battery power. They look superfine and almost elegant in dark conditions. And, after carrying around this project for a week, I decided that sometimes at night, I want to turn the lights off. In that the only way to do this was to pull out the battery, I added a switch. I poached the switch from the IKEA Glansa LED battery pack from which I cut off the string of LED lights.
If you are an electrical engineer, please post your enhancements in a way that true beginners can implement them. We all enjoy using information that helps to make our projects better. And I know there are certainly things that can make this project better.
Here are the steps for making the solar Christmas lights. (Like during high school mid-terms, I would read all of the instructions before you begin this project.)
1. For this project, I chose a solar garden light with a photo sensor built into the panel. It makes things a bit easier. Solar garden lights with external photo sensors have a white bump, which is the photo sensor, near the solar panel. The ones with the sensor built in have no white bumps anywhere. The sensor is a silver strip.
2. With a screw driver, remove the cover of a solar garden light. Cut out the solar panel from a solar garden light. Make sure you don't cut through anything important. I used a thin pen knife. No rush, take your time. The plastic is pretty soft. I actually separated the plastic battery holder from the panel for this project. That is why there is old glue everywhere. You don't have to do this, just make sure that when you are done, the solar panel and attached circuit can fit in an Altoids box.
3. Put the Altoids box face down, and trace around the panel, so you get know the correct size of the hole you will cut with the Dremel. WEAR EYE PROTECTION, and cut out the hole, You can't ride a bike very well with bits of metal in your eyes.
4. Drill a hole in the end of the box. This is where the lights will come out. Again, protect your eyes from any flying bits of metal. Drill from the outside in, so any sharp pieces are facing inside the box away from humans. Make sure to choose a drill bit that allows for a big enough hole for the lights.
5. A few lunch runs ago, I got a mini glue gun for $4.39, so now I can get hot glue all over myself, my clothes, and my workspace. Put down a thin ribbon of glue and press the panel into place, so it faces outward, and the photo sensor is not covered. The circuit and battery should fit into the box with the lid closed. (I took this photo for illustrative purposes after I had completed the project, that is why there is why you can see a wire coming out of the box.)
6. Look at where the LED is soldered to the circuit board. You don't want to touch a battery with a soldering iron, bad idea. Take out the battery, and desolder the LED.
7. Then, making sure there is no battery in the IKEA Glansa LED Christmas lights, cut off the string of lights. Remove the insulation from each strand, and stick one wire from each side of the strand into the holes in the circuit board that used to hold the LED. The LEDs should light up if the positive wire is in the positive hole and likewise for the negative wire. If they don't light up, you may have put the positive wire in the negative hole. So, switch the wires.
8. When you have determined the correct position for the wires, thread the lights through the hole in the Altoids box, and solder the wires into the correct holes. Since I got the glue gun, and was making a mess, I put a gob of glue on the wires leaving the box to protect them from being pulled out of the circuit board.
9. If you want to make the light string longer, you can cut off the very last light on the end of the IKEA lights and solder another string of IKEA Glansa LEDs to it. Make sure you match positive to positive wires and negative to negative wires. If the LEDs light up, you have it right. If not, switch the wires around. Cover the connections with clear tape, if you can, for protection. Black tape, for this application is kind of overkill, and bad ugly. So far, I have about an 11-foot string of IKEA Glansa LEDs attached to the circuit in the Altoids box. This gives me much cheer.
10. In that I wanted to be able to turn off the lights after the shop closed, and the only way to do that with the circuit design was to shine a light on the solar panel, I added a switch. Desolder the switch from the IKEA Glansa LED light battery pack from which you cut off the LEDs.
11. Solder one end of the wire hanging from the switch to the metal tab coming from the battery. I picked the battery tab that has a wire going directly to the circuit board and has the least amount of wire who-ha going on around it. (In this case, it was a blue wire.) I put the switch on the inside of the Altoids box, so the case looks clean, and the switch doesn't catch on anything. The lid to the Altoids box is hinged and easy to open and close. Remember: The switch has to be turned on again in the morning for the circuit to work its magic. I took the parts that held the switch in place in the IKEA battery pack and reused them by flipping the holder upside down and using the glue gun. So, the switch is glued to the flipped over holder. It is more stable, and it fits neatly inside the Altoids box.
12. And there you go, a little solar LED Christmas light joy this holiday season coming to you from the Wheelgirl bike shop.
All photos, in questionable light and conditions, taken by Wheelgirl.