Motivated by lack of available custom booklights, I am making a custom lightwedge. The idea behind it is very simple. The lightwedge is simply two LEDs, a resistor and 6 volts. the part that costs $25 is the light guide. The light guide has tiny angles in the casting that reflect a tiny part of the light evenly over the page of the book.

My plan is to cut the lightwedge to the right size (as detailed in the third picture lightwedgemode.jpg), add a new switch and a batter pack that clips onto the back cover. I'm going to try to use the magnets in the ebook to attach it, but I suspect they won't be strong enough to hold the heavy plastic.

I don't think it will be very hard, but I don't have the right tools right now to really get started.

Where did you get the tapered plastic? That is the hardest part to get a hold of.

You can get rare earth magnets from leevalley.com .

Where did you get the tapered plastic? That is the hardest part to get a hold of.

You can get rare earth magnets from leevalley.com .

He took a original Lightwedge apart. I have been looking also for the materials to make one myself. I think I will wait and see if this is the way...'You can do it!" :D

He took a original Lightwedge apart. I have been looking also for the materials to make one myself. I think I will wait and see if this is the way...'You can do it!" :D
I'd like to add a light wedge in one of my cheaper boxes. I can just picture this; open the lid, flip up the lightwedge, insert the reader, turn it on, flip back the wedge, turn it on also and read... :shy:

I have asked a friend visiting USA to buy Sony Reader for me. It will take quite a few weeks until she returns from her trip.

In the meanwhile I want to prepare for making myself a homemade lightwedge.

I am planning to buy a thick (cca 10mm) piece of acrylic "glass". (That will be a slight problem, because everyone wants to sell me 1.5m x 2m piece and all I need is an A4 sized piece).
First I will cut the acrylic into the desired size + 5mm on each side.
Then I will glue it into a board, using cca 10 mm thick spacer, so it is coplanar with the board and is above the surface of board. I will put a screw to the each corner of the board.
Next I will take a long piece of coarse sandpaper and glue it flat to a large flat surface. Now I take the board and position it above the sandpaper so it stands on four screws with the acrylic touching the sandpaper. Screws will be standing next to the sandpaper and will be able to slide very easily.
Then I will spend some time sliding the board back and forth so the acrilic grinds in the sandpaper. By adjusting the screws I will be able to make precise wedge.
When the wedge is done I will use finer and finer sandpaper. The final grinding will be made with a sandpaper used for finishing automobile paint on a rubber block.
I will finish the surface using polishing paste. You can get amazing results with polishing paste on acrylic.

I have been working with acrylic before and it can be grinded very well and very rapidly. By polishing it you can make it look very, very nice and proffesianally made. Acrylic can be also bent and formed when you heat it very carefully. Be prepared to waste a lot of material until you get it right.

Disclaimer No. 1
Lightwedge is probably patented, so use this only for your "personal educational purposes"

Disclaimer No. 2
If you have no experience working with wood and/or acrylic and if you value your time at more than 2 bucks per hour you will be much better off buying the original LightWedge and trimming it to your needs. But FIRST PRACTICE ON A PIECE OF ACRYLIC YOU ARE WILLING TO THROW AWAY. Acrylic has peculiar properties then you try to saw through it.

Disclaimer No. 3a
I am going to do this for fun and I have well equiped workshop.

Disclaimer No. 3b
I have no means to purchase Lightwedge
Even purchasing Sony Reader is very complicated for me.

Disclaimer No. 3c
An average salary in my country is magnitude less then in USA. (so I consider $25 to have much greater value than most of you)


I will do this project when I get Sony Reader into my hands, so I can make a perfect fit. I will post photos of all steps, but do not hold your breath ...

Well, I decided to work with what I have. A Dremel rather than a bandsaw. i'll have to say I'm happy with the results sofar.

Can you cover the LEDs? You seem to be getting quite a blast of light in the face there. That makes it too distracting to read comfortably!

I put the thing together last night and read for a couple hours. Those 4 AAA batteries and the lexan add about 4 ounces to the weight. I had noticed the lights to the face problem prior to bed. I used masking tape to cover the LEDs, Yvan.

Still needs a new switch and I need some strip aluminum to screw the thing together structurally. I seriously doubt that two neodynium magnets by themselves could hold JUST the tapered lexan piece in place, much less with full battery pack and things. It's going to want to pull off from the left side of the screen, so I need to add a hook that will grab the reader from the left and latch on the right with the magnets.

Hey Yvan, I'll trade ya for your sweet wooden book holder :)

I put the thing together last night and read for a couple hours. Those 4 AAA batteries and the lexan add about 4 ounces to the weight. I had noticed the lights to the face problem prior to bed. I used masking tape to cover the LEDs, Yvan.

Still needs a new switch and I need some strip aluminum to screw the thing together structurally. I seriously doubt that two neodynium magnets by themselves could hold JUST the tapered lexan piece in place, much less with full battery pack and things. It's going to want to pull off from the left side of the screen, so I need to add a hook that will grab the reader from the left and latch on the right with the magnets.

Hey Yvan, I'll trade ya for your sweet wooden book holder :)
:happy2: Yeah sure! With a couple of greenbacks it's manageable. :happy2:

Great, I agree the LightWedge-around solution is one of the best for reading.
Did you see my similar homemade lightwedge?


post #77:

http://www.mobileread.com/forums/showthread.php?p=52202#post52202

Yes, it was my inspiration to get off my butt. I have pictures of the final design, but my card reader isn't working properly and I can't get them right now.

Well, I decided to work with what I have. A Dremel rather than a bandsaw. i'll have to say I'm happy with the results sofar.
Have you thought about wrapping the edges with aluminum tape to seal them? You might even get enough reflected light to increase illumination of the Reader.

Have you thought about wrapping the edges with aluminum tape to seal them? You might even get enough reflected light to increase illumination of the Reader.

Actually, flame polishing the edges provides a significant reflection effect by itself. I'm considering wrapping the edges simply because the light that does get through is too bright and illuminates the room.

You have to think about covering the ughly green fibre! A nice wood cap would do it! :happy2:

Yes, that would be great! But, I've been rethinking my design and I think I can eliminate the circuit board altogether in a future revision. I've come pretty far with this design and think I might need to start with a new lightwedge for version 2. I think obelix is correct in abandoning the 4AAA batteries and working with a mobile phone battery.

By simply hot-gluing the LEDs into the lexan and integrating the battery and switch into a "backpack" like Obelix, the magnets could probably be used to attach the lexan to the reader and it would look VERY sleek.

You might want to use some watch (button) batteries instead of the AAA's. Smaller size & less weight & should be plenty adequate for LEDs.

Yes, it was my inspiration to get off my butt. I have pictures of the final design, but my card reader isn't working properly and I can't get them right now.Hey, maybe if you get the thing all worked out, it will be LightWedge's inspiration to get off their bu++s and make one also!

Maybe Vaporware can forward a functioning prototype to them with a note that says something like: "C'mon, LightWedge, it ain't rocket science!" :mad:

I think obelix is correct in abandoning the 4AAA batteries and working with a mobile phone battery.
Have you checked the Reader's USB and/or dock ports to see if you can source power from either of them?

Nah, I'm pretty sure you can't tap the battery from the reader, besides it would be the equivalent of hooking up a big screen TV to a scooter for power. a 3.7v 900mAHr battery like I'm planning on using for the lights is probably bigger than the reader's battery!

My next design will be much more like obelix's light and less like a hacked lightwedge.

The USB port doesn't give power -- Sony said so, and I've checked it myself. :grin:

The SD/MMC card port might, I haven't tried it. In any case, I tend to agree with Vaporware about the moped/plasma TV thing. Nice visual that. :laugh4:

How about the power port itself?

Heh, I haven't tried the power port, but those things are usually one-way. I can't check it right now 'cause my DMM (http://en.wikipedia.org/wiki/DMM) is at home, and I'm not. :nice:

You might want to use some watch (button) batteries instead of the AAA's. Smaller size & less weight & should be plenty adequate for LEDs.

I'd vote for AAA's -- I want to use rechargables. When I travel I always carry a fairly small dual voltage charger. I don't want to have to worry about what they call this and that watch battery in foreign country :)

Actually, if the power pack is separate, one could have options for both.

I tend to agree with Vaporware about the moped/plasma TV thing. Nice visual that. :laugh4:

Actually his visual is incorrect. These light designs have at most 2 LEDs, you can run two in series so the current draw is roughly 20ma. 900/20 = 45 hours.

Not exactly a "plasma screen" load on the Reader's battery.

Power sourced from the Reader would be regulated so all you need are 2 LED's, a drop resister to set the ma's and a connector to provide a nice stable light source.

Scotty! Could we get power from the reader's power port?

Actually his visual is incorrect. These light designs have at most 2 LEDs, you can run two in series so the current draw is roughly 20ma. 900/20 = 45 hours.

Not exactly a "plasma screen" load on the Reader's battery.

Power sourced from the Reader would be regulated so all you need are 2 LED's, a drop resister to set the ma's and a connector to provide a nice stable light source.


I think a consistant 20 mA draw would be a serious battery drain on something that only draws on page refreshes, but then again it's probably less draw than the music player.

Scotty! Could we get power from the reader's power port?
I've been out of town all weekend, so I'll check after work.

I think a consistant 20 mA draw would be a serious battery drain on something that only draws on page refreshes, but then again it's probably less draw than the music player.

It'll only draw 20ma when it is turned on. And from the looks of the pictures posted 20ma might be a teensy bit too much juice.

Scotty! Could we get power from the reader's power port?

If I were a Sony hardware designer I would have made a play to management to make power available on the dock port so we could introduce a thumb board at some point.

The power port should have a low forward voltage diode to protect the device from reverse polarization of the power cable. The diode would have the side effect of preventing power being tapped from the device via that port.

Obelix, how the heck did you solder that FAN5607? If you could, could you explain your circuit? I am interested in reproducing your design.

Obelix, how the heck did you solder that FAN5607? If you could, could you explain your circuit? I am interested in reproducing your design.

1. Glue the chip legs-up to the small piece of the circuit board.
2. With regular soldering iron (RadioShack $10) solder thin wires (extracted from multiple-strand wire) to the legs (be careful, do not touch them for more than 1 sec).
3. Put pieces of plastic tubing on the wires to isolate them.
4. Solder the opposite ends of the wires to capacitors and resistors soldered to the board at the earlier step.

Hint: You can get capacitors (of the type needed for the circuit) from any broken computer electronics. I got mine from damaged hard drive. Just take the biggest capacitors located at the power connector (box-shape, brown color). I did not care much about capaciance, I built 2 units and they both work fine, I think capacitance is not that important.

Sorry, I dont know exact English terms for many things like that, so if you will need more information, please drop me a message to m_ryb AT netzero DOT. com, if needed I can do more pictures.

Ok, I'll give it a try this week. I have the instructions from the manufacturer, but I was wondering how you use the potentiometer to vary the brightness? it explains how to use a voltage divider to vary the brightness by changing the input voltage. Is that how you used the pot?

Another option for powering white LED's.

http://www.national.com/ds.cgi/LM/LM2703.pdf

You can buy an evaluation board: http://www.national.com/pf/LM/LM2703.html

It will happily run off 2 AA/AAA's and drive up to 4 white LED's with an efficiency of around 90%.

Ok, I'll give it a try this week. I have the instructions from the manufacturer, but I was wondering how you use the potentiometer to vary the brightness? it explains how to use a voltage divider to vary the brightness by changing the input voltage. Is that how you used the pot?

With Rset (I used 100k potentiometer, the central pin and one of the side pins are connected together; the 3 pin potentiometer becomes 2 pin variable resistor).
Schematic is the same to the one shown on the page 1 of the datasheet (except I used 2 LEDs, 2 other pins are unconnected), for the Rset vs output current see table on p.9).

http://www.fairchildsemi.com/ds/FA%2FFAN5607.pdf

I was considering also LM2703 (and even purchased one), but it requires more elements (including 10 uH coil). FAN5607 requires only 4 ceramic miniature capacitors.

... I was wondering how you use the potentiometer to vary the brightness?Brightness on an LED is a function of current, not voltage -- it requires a specified voltage to work at all. :nice:

As obelix explained, you just wire up the center post (the wiper) and one of the side posts and the result varies the resistance, which for a constant voltage, varies the current (Ohm's Law (http://en.wikipedia.org/wiki/Ohm%27s_law), and all that :)).

The only things I'd add are:

You can, if you want to, also connect the wiper post to the other side post (in addition to the center one, wire them together I mean) -- it doesn't really make any difference electrically, but it looks a bit neater to some folks. :shrug:

I'd suggest you connect your power to the post clockwise from the wiper post, that way as you turn the potentiometer clockwise the resistance will decrease, increasing the current and the LED brightness, and counter-clockwise will turn the LED 'down' -- that's the way most folks expect controls to work (clockwise 'up' and counter-clockwise 'down'), so it's usually more intuitive. :shrug:

If your potentiometer isn't obvious about which post is which, you can always test it before you soldier the connections. :nice:

Ok, I'll give that a try. I knew about the current thing natch, I was talking about how in the FAN's instructions they have a PWM brightness control in the chip and a voltage controlled dimmer, but I never noticed the R v I table on page 9.

I liked the explanation about pots, so thanks for that.

I'm pretty thickheaded about electrical circuits, but if I think about them long enough I can normally handle a simple one.

I used to do BEAM analog robots, but I never got those things working.

Ok, I'll give that a try. I knew about the current thing natch, I was talking about how in the FAN's instructions they have a PWM brightness control in the chip and a voltage controlled dimmer, but I never noticed the R v I table on page 9.Ah, sorry to tell you stuff you already knew. The LED Current/brightness thing was something it took me a while to get in my own head, so I jumped to the wrong conclusion. :sad:

Glad some of it was useful anyway. :nice:

No problem Natch, I have a lot of trouble with figuring out the required resistance to get the right current, so I'm in the same boat, just a different end.

I'm going to try the FAN circuit tonight, But I really need another lightwedge panel so I don't have to rip my current one apart :|

Electronics are so fun and scary at the same time.

No problem Natch, I have a lot of trouble with figuring out the required resistance to get the right current, so I'm in the same boat, just a different end.At the risk of telling you something else you probably already know (;)), just divide the voltage you have by the current you want and you'll get the resistance as the product. You just have to remember to adjust for the Current's units (i.e. if you're using mA, multiply by 1,000 to get Ω's instead of kΩ).

Ahhh! It feels good to actually use something I learned from my College Degree. :grin:

Ok guys I've started soldering this thing up. Holy moly those solder pads are incredibly hard to solder. I need to know how to wire it up. I'm connecting V+ to the Vin pin with a 4.7 uF cap going from + to grd. V- connects to Vout with a 4.7 uF cap from - to grd.

uh, what is ground in this circuit? do I just solder the GRD pin and the caps negative leg to together to get ground?

Ground is gonna effectively be the negative terminal of your power supply.... :nice:

So I would solder both leads of the negative filter cap to the same terminal ? this is so confusing. You can see it on the Vout terminal in the picture.

By the way, Obelix, your method of breaking up stranded wire was brilliant, and it allowed me to finish soldering to the rest of the terminals. of course it took me all night, but I got it.

You're right, that doesn't sound right. :no:

Ah, I think I see the problem, Vout isn't V-, it's the output power for the LEDs.

Here, I've marked up the schematic a bit, blue for Vout and yellow for ground/V- connections, hopefully that'll clarify it some. http://www.fastlanehw.com/forums/images/smilies/fingersx.gif

Ohhhh Duh. Yeah. V- will be ground, not Vout. Oh well, that's what I get for trying to work at midnight.

Yeah, my brain shuts down around 11:45pm, too. :grin:

Well, I finished, but I think I burned the chip. I get 2V across Vout, but none across the LED+. I'm going to try for a second chip.

Well, I finished, but I think I burned the chip.You can't let the magic smoke (http://en.wikipedia.org/wiki/Magic_smoke) out. :no:

We used to call it 'slagging' the chip, cause after you let out the magic smoke, it's just so much slag. :sad3:

Ok, I've finished the second one, but still no results. I don't know what's going wrong because I certainly didn't overheat this chip.

Ok, I've finished the second one, but still no results. I don't know what's going wrong because I certainly didn't overheat this chip.

I've made zoomed image of my box. Please have a look.

Ok, I'll try to track down a Different source to get my Ceramic chip caps, I was pulling them out of a 10 year old CD player and they have got to be the weak point. I'll track them down this weekend since I'm going to be away from my soldering station anyway.