The Wind-up Headboard Reading Light

Step 10 Attach base to headboard, wind and enjoy.

As mentioned before, despite the fact that this lamp is kind of ugly, the clamp would be crossing some unseen ugliness boundary line in our house. Instead, I used three screws and attached the block directly to the back of the head board. held my breath until I was sure the screws wouldn't pop through the front of the headboard.

Firmly attached, I gave the unit a one minute wind, then turned it on.

I love that feeling. That little sense of quiet accomplishment. Good times.

Overall, I learned a lot on this project, especially on soldering and de-soldering, and I have now achieved my objective of taking this room off-the-grid.

As always, though, there are thoughts of v. 2.0 floating around in my head. They center on two main areas for improvement: power and aesthetics.

Power: I am getting about 15 minutes out of a 2-minute wind right now. suppose if I use a chargeable battery with more capacity, I could get more time. But my supposition is there must be wind-up units that put out more power and store it in larger batteries than this one. If you are someone who knows of such things, please leave a few comments.

Aesthetics: Obviously, I was not tying to build the most gorgeous lamp int he world, but I truly believe you can do this project in a more-beautiful way. I'd love to see that.

Finally, there is the funky blue LED light, which takes some getting used to. For v. 2.0, I think I'd want to add more LEDs and look for a filter of some sort that could warm up the quality of light for me.

But overall, I'm happy today as I write up my first-ever instructable, and tell about my small contribution to green up my life in Central Ohio. I hope you have enjoyed reading along.

Good times.

Comments

[grinnin]

I love this idea. I think this would be about the right amount of time before I'd fall asleep. Some smart person....please refine this off the grid wind up light!

[Kagetsuki]

Any high torque low speed (rpm) motor will make a half descent dynamo. It looks like that's what your flashlight there has. If you want a more powerful dynamo to charge your batteries just scavenge around and you should find something. But be aware you need to build a charging circuit that will allow you to safely and effectively charge your batteries. I'm of course assuming that's a battery pack there. It may be a stack of super capacitors or something like that. Batteries are usually hard to charge and charging often takes quite a bit more energy than you may expect. I'd be interested in hearing how much voltage is being put out and how much voltage that dynamo/motor you have there generates when it spins. For batteries, you really can't put energy in in reverse (generates heat and could ruin the cell), and charging at overly high levels can ruin them as well. Capacitors will take charge very quickly, but the amount of charge they can hold is limited. Super capacitors can hold quite a bit more energy due to their delicate inner composition, but that same delicate inner composition is weak against even lower voltages. That pack that appears to be a stack of batteries may well be a stack of super capacitors, employed because they can take a large charge quickly without taking a lot of space. In this particular situation however, space isn't a problem. You could hide a huge capacitor or a whole bunch of them behind the bed board. Couple that with a big fat powerful dynamo and maybe a gearbox to get more bang per crank and in two minutes you may have enough power to run that 5v LED lamp all night.

[Fake_Name]

I don't know of any small brushed motor or generator that produces useful power at a speed you can reach by hand (60-120 rpm). Most small motors work best at ~300 to several thousand RPM. The motor in the flashlight is fairly heavily geared up, to generate a higher voltage. If you could track down a brushless AC motor, you could probably use a voltage doubler or multiplier to get an output voltage high enough to be usefull, but gearing is still preferable (Voltage multipliers can't source much current). Incidentally, the green heatshrunk thing is almost definitely 3 "coin cell" NiCd rechargeable batteries. That gives you an overall system voltage of 3.6v, which can drive white LEDs with a minimum of energy lost in the limiting resistor. The output from the motor/generator is probably simply rectified before being applied directly to the battery. It's not very good for the battery, but considering how cheap those flashlights are, who cares. It will, however, considerably reduce the cycle life of the battery/

[Kagetsuki]

It's not necessarily about being able to reach the motors rated standard operating RPM, but simply that motors with lower RPM and higher torque tend to be better dynamos. You mentioned gearboxes (which I mentioned only briefly), and that's one part of the equation that probably needs to be focused on just as much if perhaps not more so than the motor. Of course finding an appropriate gear box can be difficult, and I don't know a simple way of reliably building your own. If anyone knows of a resource on how to build your own gear boxes I'd love to see it. As for an AC motor, couldn't you just use a transformer? To hear that the heat shrunk thing is in fact battery cells is surprising to me. Batteries are notoriously fragile and fickle. Not to mention charging them usually takes quite a bit of power. But if for two minutes of charging those things will hold for 15 minutes, and continue doing so for an extended period, perhaps I have underestimated modern battery technology. If I remember correctly charging and discharging Ni-Cad batteries under 20% full capacity ruins them, and with a system like this I could see just that situation. I guess since it's such a cheap device that's not an issue? If those are in fact just Ni-Cad batteries and the dynamo is in fact just wired straight up to them; it's amazing to see something which would appear to be built so inefficiently work so well.

[peterwbrown]

Just to update - the light I got from this flashlight became less and less over time, and now the lamp isn't really usable. I love this idea, but don't have the skillz I need to get it to the next level.

[Kagetsuki]

Lights wear out and so do batteries. Especially in the case of LEDs, too much power will burn them out. It just so happens I burned out an LED today, and it now gives me only a dim glow. To a degree I actually did this on purpose because I wanted to stress test this model, and luckily it only cost me a few Yen and I have 998 more in a bag. What would have caused your LEDs to burn out would probably be having source voltage too high without enough resistance in the circuit to reduce the current to an acceptable level. If you have too much voltage hitting the LED and your power supply is a good current source you will burn it out as the internals of the LED. You can check how much current is going through the LEDs with a multimeter, if it has a MAX hold on it all the better as you'll be able to catch the maximum current going through the circuit at any point in time. Since many LEDs operate best at our around 20ma (or for higher power white or blue LEDs often 50ma or so) if your current is beyond that of the current recommended in the data-sheets you are overtaxing your LEDs and that is causing them to burn out over time; resulting in them slowly dimming. The other possibility is the batteries are simply fatigued/worn out. I am not personally aware of any battery type that works "well" with erratic charge cycles and this application is about as erratic as it gets. I'm not sure how much voltage these cells were providing at peak, but if they are providing less after a full charge session now then they are probably "dead". One thing to note is that despite providing a particular voltage it is very possible the batteries will not be able to deliver enough current to meet that voltage, which will usually display as a sudden sag in voltage once the circuit is connected. If you would like to try and diagnose the problem I'd be willing to help you out as best I can. In general where to go from here would be: 1. Since you salvaged your lights from a USB lamp, and assuming you have not changed the internal wiring, try reconnecting that portion to a USB cable and plug it in to a USB port (or a 5V power supply). If your lights turn on and are bright they are good, if they are dim then you burned them out. 2. Regardless of weather or not your lights are burned out or not your batteries are suspect. Is there a peak voltage written on the battery package? How does the battery pack measure with a "full" charge now? Is the battery pack NI-MH/NI-Cad? If so, you can simply replace it with a set of store-bought NI-MH rechargeable cells. Each cell comes out to about 1.2V, and if you put them in series (+ to the - of the next battery) the voltage adds up. If your batteries are worn out replace them with new ones. 3. If your LEDs were burned out then your circuit is providing too much power, figure out how much power is being delivered by metering the terminals which you connected your LED strip to and apply an appropriate resistor to bring the power down to acceptable levels. Then, connect a new strip.

[Kagetsuki]

Oh, and I don't want to give the impression LEDs normally burn out. Proper LEDs when operated within specifications will often be rated to not noticeably fade for 10+ years of continuous operation. Lower quality LEDs will often wear out much quicker, but still in the range of years of continuous operation.