Foldable Electronic Bookmark / Booklight




Introduction: Foldable Electronic Bookmark / Booklight

This project is not only really, really fun to build, but also fun to use. If you love books or know someone who does, this is an awesome project to make. It is extremely light and literally paper-thin. It is also really easy to personalize and the battery pack design can be used for any small project when you need a 9V battery, but need to save space.

Step 1: Materials

There are actually only a few materials that you will need to make this project, and a lot of them are inexpensive and interchangeable with other items that I will explain below.

- Scissors

- Pencil/Pen

- 3 coin cell battery's (each 3V)

- Glue stick

- Tape

- Ruler

- Card stock (any color and size)

- Super bright SMD LED's (These are interchangeable with chibitronics circuit stickers which I will explain how to use later along with a circuit scribe)

- Copper tape (This is interchangeable with a circuit scribe pen or other conductive ink)

- Print-out of the battery box which is attached (preferably on card stock, but printer paper should be fine)

List of optional materials:

- Wires and soldering iron

- Battery snap and a normal 9V (if you don't want to make the battery box)

- Origami paper

Step 2: Folding the Base

Like I said before, you can use any color and size of card stock you want, but the one above is 18x6cm if you want to measure all of the materials out exactly.

First, your going to valley fold it in half. Then, valley fold the top half in half again. Measure out 1cm from the bottom and make a valley fold. Then, make a mountain fold from the 1cm line to the crease in the middle.

Now you're done with the base!

Step 3: Adding the Negative Copper Tape on the Back

Measure out approximately 30 cm of copper tape and cut it in half to get two thin strips of 30cm copper tape. Take one of them (this will be the negative side) and place it about 2cm from the edge going all the way up to the top.

Step 4: Adding the Positive Copper Tape to the Back

Take the other strip of copper tape and bring it 3/4th of the way up the paper and cut it. Then, measure out 4 pieces of 2cm long copper tape strips (not divided in half). Overlap two of the four pieces on the end of the copper tape (as in the photo). Then take the rest of the positive copper tape and track it the rest of the way up until you are a couple centimeters from the top.

In order to make a bend in the copper tape fold it backwards and then up (or down) in the direction you want to go.

Track the positive copper tape so that it lays a few millimeters from the negative copper strip, but don't let them touch! This is very critical, don't let the positive side touch the negative side at any point along the piece of paper.

Take the last two copper tape snippets and overlap them on the other side of the positive strip (as in the photo).

You can add tape, if you want, over the negative side, but it is completely optional, I would actually recommend that you do this at the end after you debug for issues because it can cause problems later.

Now you are done with the backside!

Step 5: Placing the Copper Tape on the Front

Flip it over to the front side and take the negative piece of copper tape and make a wide U shape in the top quadrant. (To see how to turn the copper tape, review the tips at the beginning). Then take the positive copper tape and have it run parallel to the negative one (If you haven't noticed already, this is a parallel circuit). They should be millimeters from touching, but don't let them touch!

You are now done placing copper tape on the base, but don't put away the copper tape just yet! We will still need to use it for the battery box.

Step 6: Adding the LED's

I can't remember exactly what size the LED's are, but from what I remember they where called super bright SMD LED's. I got a whole lot of colors for very cheap, but they are very fun things to place with.

This part can be a little tedious, I can't tell you how many times these little LED's have magically disappeared from my finger. Hopefully my little technique will help.

Peel back the protective plastic and place a small piece of tape lightly on the top. It will usually jump up onto the tape, but you can shake it a bit to get it to stick. There is usually a green arrow marked on the bottom, it is always pointing in the direction of the current, so positive-->negative. Make sure that the green mark is going on the bottom and that you place the arrow pointing to the negative strip. Also make sure that the LED is connected to both the positive and negative copper tape. I know that it can be difficult to see, but it is very important! You can place as many LED's as you want, but I added one on each edge for a total of 3, which works perfectly.

Step 7: Testing the Circuit

Before we add the battery, it is a good idea to test the circuit and lights to make sure everything is working the way it should. I just hooked up a 9V and pressed the "switch" together that would go in the pages of the book. If your LED's don't light up, try pressing on them, or flipping them. If that doesn't work then there is probably something wrong with the copper tape (it could have torn at one of the creases). You can use a voltmeter to see where the problem is, but I don't have one so I just use Dr. LED in place of it :). Place it in different spots on the circuit and if it light up then the circuit should be good up to that point, if it doesn't then there is a problem behind where you placed the LED.

Step 8: Measuring and Battery Options

If you want you can just use a 9V with a battery snap and solder it to the copper tape, like the picture. BUT, there is a better way! I didn't want to have a heavy 9V battery hanging out of my book every time I use it, so I created a battery box that connects 3 3V coin cell battery's in series. I absolutely love this little battery box and I use it for all sorts of projects now. The coin cell battery's that I used to design the box for are 2cm in diameter and 1cm thick when placed all together. So measure your battery's to make sure they will fit in the box because they need to be really snug.

Step 9: Preparing the Battery Box Template

Print out or trace the template on card stock (printer paper also works, but it is not very stable). Cut it out and valley fold along all the lines specified. Don't forget to cut the little slit indicated on the template, this is where the positive end of the copper tape comes out.

Measure out approximately 10cm of copper tape and cut it in half.

Step 10: Putting Copper Tape on the Battery Box

First lets start by taking on of the pieces of copper tape (call it the negative piece) and tape it from the bottom of the longest bit up to the edge of the center square (as in the photo).

Then flip the box over and take the other piece of copper tape and place it in the middle of the center square in the shape of an L and thread it down though the slit that you made earlier (as in the photo).

That is all there it to putting the copper tape on the battery box, but leave the copper tape hanging for when we attach it to the base.

Step 11: Gluing the Battery Box Together

For this part the pictures are pretty self-explanatory. Wherever there is a white dot on a tab, you place glue. Then, just follow the direction of the purple arrows to see where the tabs go.

Once everything is glued together and assembled we are ready to test.

Step 12: Decorating and Testing Your Battery Box

I put some decorative origami paper around my battery box because the box is the part that sticks out for decoration when you use it as a bookmark. Put the battery's in positive side down and gently stack all three on top in the same way. Slide the closing tab in, make sure it is above the negative flap on the inside otherwise it will interfere with the connection. Test it out with an LED. As you can see, it is just as bright as the 9V.

Step 13: Attaching the Battery Box to the Base

Now lets put them together! Cut out another piece of card stock (make sure that the material that you chose for this part is strong yet flexible) that measures 2x5cm. The length isn't too important, just make sure that the width is 2cm. Glue the Battery box on the edge and press down the copper tape a little ways along the strip. Glue the end of the strip in the middle of the base up to the edge of the 1cm crease mark. Lay down the copper tape and fold it over so that is lays on top of the positive and negative pieces of copper tape. Trim the ends and press the copper tape firmly. You can tape the back for added security.

Step 14: We're Done!

Now you can test it out and use it in your book! In the video you can see how it is transformed from the flat book mark to the folded book light. There are so many variations that you can make, and I have a small collection forming of these handy things. I hope that you enjoyed making this! I would absolutely love to see any that you decide to make.

Step 15: Debugging Tips

How to change directions with copper tape:
This is how I figured out how to do it, but if you know of another way, you can do that too.
Fold the copper tape backwards and make a small crease with your finger then fold it in the direction you want to go. (I think the photos will be better at explaining this than a description)

Is yours not working and you don't know why? There could be a few reasons:

1. Your LED's or battery are not flowing in the right direction. Try flipping them.

2. Your LED's might not be right on the copper tape. Try pressing or shifting them a bit.

3. This is a really tricky one to catch, but a strip of your copper tape might have split at one of the creases. To mend it, just place another piece of copper tape on top.

4. The battery box flap might be blocking the negative terminal. Try repositioning it.

5. A short might have occurred by the LED's (because the copper tape is so close). Check to see that they are not touching.

Hopefully it will work now :)

Step 16: How to Make for Circuit Stickers and Circuit Scribe

Using Circuit scribe and/or circuit stickers for this project make it way faster to make! It took me half the time and it is more resistant to wear and tear. It is made in the same way, but you can use just one LED instead of three this time. Copper tape will still work when you lay it over circuit scribe. Obviously other conductive inks will work in the same way. Also the battery box was still made with copper tape due to the surface not being easy to draw a continuous line on.

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    7 years ago

    Neat and awesome


    7 years ago on Introduction

    Very minimalistic design. Loved it. Power source should be much smaller(may be in future when batteries gets smaller and powerful), its still bit heavy considering the rest of design.

    Priya Rao
    Priya Rao

    7 years ago

    Itz really wonderful.. itz winter so i realy like to get inside my quilt n read a book.... thanku fr diz awesome idea....

    Akin Yildiz
    Akin Yildiz

    7 years ago on Introduction

    very simple, creative and detailed instructions. i really like this !!


    7 years ago

    How lovely! Just what I've been looking for - a nice little book light? Love the dual purpose functionality, too. Thanks!


    Reply 7 years ago on Introduction

    Yes, it is so fun to use! Thank you!


    Very nice - love the simplicity.

    However, most LEDs are 3V - wouldn't 9V kill them soon? Also, it would probably make sense to add a current limiting resistor to save the LEDs from harm.


    Reply 7 years ago on Introduction

    Thank you!

    Thats a good point! I found that by cutting the copper tape in half it adds some resistance to the circuit, but I don't have any SMD resistors and traditional resistors would require soldering and might make dents in the book. Chibitronics make a good replacement though!