Instructables
Picture of The Wind-up Headboard Reading Light
I love to read in bed.

This is one of the true pleasures in my life, and I begin and end every day doing it. One day, I was reading an article about living off-the-grid, which seemed like a neat idea, but also a real stretch for a production home suburbanite like myself. But then the author suggested taking just one room off the grid, as a small start, a way to act, a way to learn.

I realized that the bedroom was the best candidate here. We plug in only an alarm clock and a reading lamp in here. What's more, I frequently fall asleep while reading, shutting the lamp off only the next morning.

I first tried a battery-operated book light, but was underwhelmed. It kept getting in the way and the light fell inconsistently on the page. Call me crazy (and I'm sure you will) but the best place for a reading lamp is about a foot up and over your left or right shoulder.

My next attempt was tape-mounting a wind-up flashlight up and above my right shoulder, but it was a graceless attempt and prone to falling. Also, you had to un-tape the flashlight to wind it up. I'm not even going to repeat here what my wife said when she saw it.

So I decided to combine the two ideas - wind-up power with a headboard mounted reading light. A form factor change that uses zero electricity from the grid (and in Ohio, our electricity is still, inexplicably, coal-fired) and had the added benefit of shutting itself off after 30 minutes or so.

This instructable is how I built my wind-up headboard reading lamp. Be forewarned: I'm not an engineer, nor a designer. I'm not even particularly handy. I'm just a guy in the suburbs of Columbus, Ohio who wants to do right by the Earth and still read in bed every night.
 
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TheGoodLife5 years ago
The resistors afore the LEDs lowers the current passing through each LED and prolongs their life.
grinnin5 years ago
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!
agis685 years ago
Oh my friend you need 25 min to get a "piece of wood"? I need just 3-5 mins after laying in bed....and then even the canons of Navarone cannot wake me up...:D
Kagetsuki7 years ago
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.
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/
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 (author)  Kagetsuki5 years ago
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.
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.
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.
Kryptonite5 years ago
Hello, In step 7 you wrote "other instructable" twice, one being a link and one that's just normal. Update iminant? Any way, I'd advise to keep away from that nasty metal part, as you may have found, OW! It left a nasty burn on my finger, the first time I tried soldering.
Crucio6 years ago
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.

No need. You can buy "warm white" LEDs. E.g.: have a look at this
Digikey search.
Crucio6 years ago
Perhaps version 2.0 could employ solar cells (from broken garden lights) to help charge more batteries. That would relieve you of the tedium of nightly winding and also give you more run time. If your bedroom doesn't get enough direct sunlight, you can cycle batteries from the solar panels to the reading light as needed. Three AA-sized batteries (3x1.2V=3.6V) will replace the NiCads nicely and give you much better runtime.

Too good, in fact. You'll be able to run the light all night long. Yeah. That problem again. However, it's free and green. Alternatively, the extra capacity allows you to add more LEDs (doubling and tripling in parallel). In the end, you'll likely need to get a simple timer to act as a circuit interrupter. It has the added advantage that you can set the power on time duration.
T-K6 years ago
You're a cute sleeper
admiral0016 years ago
I like this idea. its even better since you used the word un-solderful. hehe
Goodhart7 years ago
Although a battery powered "headlamp" (there are some small models that are little more than a band that fits around the forehead with a small light around each of the temple areas) would work, the sacrificing of a pack of batteries every night could become expensive, not to mention irritating.
This is a rather nice idea in comparison. Being self timed (of course, a bit limiting there, but it eliminates the need for a "timer" circuit) is a plus.
In fact.......now that I think about it, I have (had ? maybe in my junk box somewhere) a similar mechanism, although it did not generate it's own electricity, it would cut off the circuit at a dialed up time (it was like an old cooking timer, with an electric attachment). At very least this would eliminate an all nighter for your AC lamp.
chuckr447 years ago
I simply use a head light, which uses LEDs, 3 different brightnesses, and rechargable batteries. Works great and I have both hands free to hold books.
xboxteen017 years ago
awesome idea and execution. great instructable
ewilhelm7 years ago
I love the project, and this is a near perfect introduction step. I love the insight into your motivation and how you approached the problem.