I needed to scan some books that were larger than 8.5 x 11 inches - in this case 9 x 12. My flatbed scanner only accommodates 8.5" wide paper. I have an iPhone app that does a great job with hand held scans, but I wanted to automate the process and provide consistent framing and lighting. So, a trip to the liquor store for a Cognac box and to Home Depot for some construction basics and an afternoon later I had a functional scanner. The dimensions will depend on the size box that you find and the length if the drawer slides. I recycled some slides from an old cabinet - mine were 20" which worked out perfect. If you have a table saw, that will make things go a lot quicker. I used MDF (fiberboard) throughout, and used contact cement to put it together. You can use pine or any other materials/fasteners that you like.
Bill Of Materials:
1. (2) pieces of 24" x 24" x .25" MDF
2. (1) piece of 24" x 24" x .5" MDF
3. One cardboard box. Mine is 14.75"L x 11"W x 12"H. It needs to be large enough for the largest document that you want to scan, and tall enough to hold the phone at a distance to capture the entire image. Cut out the top and bottom.
4. Contact Cement
5. Pair of 20" drawer slides.
6. (4) Stick-on LED battery powered lights (typically used for under cabinet installation. Home Depot or Lowes)
7. 1/2" x 1/16" strips (I used balsa wood) as a guide to slide the pages against. You could use cardboard.
8. Sheet of thin poster board or heavy paper. This is cut to the size of your pages and stuck to the bed, up against the guide strips. This is in case you have perforations on the edges of the pages, white will show through instead of black. You might still have faint shadows, but this is a big improvement.
9. Flat black spray paint. Spray the bed before attaching the guides and white paper. This helps the scanner app detect the edges of the white paper.
Step 1: Build the Base
Once again, your dimensions will depend on the box and the drawer slides that you choose. I will describe the construction using the dimensions that fit MY box (14.75" x 11" x 12").
Cut base out of 1/2" MDF. 22" x 12"
Cut (2) rails out of 1/2" MDF to mount the drawer slides: 22" x 1 5/8"
Cut (2) sides out of 1/4" MDF that basically keep the box from sliding off the top of the rails: 15 3/4" x 2 3/4"
Cut (1) crossbar out of 1/2" MDF: 11 1/8" x 1 1/8"
Before you glue anything together, I recommend that you figure out how the slides will need to mount to the MDF rails, screw them on and then glue the MDF rails to the base.
Note: The spacing of the MDF rails should be such that the distance between the outer edges should be the width of the box so that the box will rest on top of the rails and inside of the side pieces (that get glued to the outside of the MDF rails).
Glue the sides onto the outside of the rails. The box should fit nicely between them, on top of the rails.
Glue the crossbar to the tops of the rails. This really just keeps the box from sliding off the back.
Cut the rear cover out of 1/4 MDF. This just blocks the light from entering. I didn't even glue mine on, I just set it in place behind the crossbar. 11 1/8" x 5 1/4"
Step 2: Build the Tray
The tray is basically a drawer without the sides. It is where the documents rest during the scan.
Cut the tray out of 1/4" MDF: 10 1/2" x 15"
Cut (2) rails out of 1/2" MDF: 1 5/8" x 15"
Mount the slides to the rails such that when the tray is closed, the front edge of the tray is even with the front edge of the box.
Note: The drawer slides that you choose should be long enough to expose the entire tray when extended.
Glue the rails to the tray spaced apart such that the drawer slides move freely and do not bind.
Cut the white paper/posterboard to the size document you want to scan. Center it on the tray and place the guide strips on the far and right sides of the paper. Glue the guides in place, remove the paper, and then spray the tray & guides with flat black paint. When it dries, use glue stick or double sided tape to attach the white paper.
EXTRA POINTS: Device a system where you have interchangeable plates for different size paper that attach to the tray. Each plate would have the two guide strips (flat black) and the white backing sheet. In my case I just leave the guides where I had set (glued) them for 12 x 9, and when I scan 8.5 x 11, I just replace the white paper an 8.5 x 11 sheet. The scanner app compensates for the fact that it is not perfectly centered.
Step 3: Build the Lid
Cut the lid to be the same width/length of the box, maybe a little larger if you like. It needs to set on top of the open box and not fall in.
Cut (4) 5/8" strips from the 1/2" MDF and cut them to lengths such that you can construct an inner frame that will fit inside the box. This keeps the lid snugly inside of the box.
For mine, the lengths are 14 3/8" and 9 5/8". Glue in place.
On the top side of the lid, cut a hole in the center of the lid for the camera and flash. This will depend on your model of iPhone.
Attach the (4) LED lights on the bottom inside corners of the lid. I found that the double stick tape that comes with the LEDs don't stick that well to the fiberboard, so either coat the fiberboard with a clear finish first OR just use contact cement instead of the double stick tape (as I did).
Cut the top and bottom out of the box (if you haven't already). You will need to remove a little extra cardboard on the front edge so that the tray has clearance.
Put it all together, start the CAMERA app and set the phone over the hole. Move the iPhone around until the you see the white paper on the tray clearly with no shadows. Now trace around the iPhone with a pencil so that you will know where to place the phone every time you use the scanner.
The Scanner Pro app (Readdle) is awesome. Mainly because once you start scanning, you never have to touch the phone until you are all done. When you close the drawer (tray), the app will 1) detect the document edges. 2) lock on the image and focus. 3) snap the image. When you hear the "shutter", open the drawer or it will take another picture before you flip/replace the page. When the tray is open, the app shouldn't be able to lock on anything so no picture will be taken until the drawer is closed. If for some reason it does, I would spray the top of the base (and outer slides) flat black so that when the drawer is open the camera will just see black.
Unfortunately, I haven't found an Android application that works as well as this one. They all seem to require manual intervention for each scan, which really slows down the work flow.
Scanner Pro assembles all of the images into a PDF. You can set it up to automatically upload the files to your Dropbox account. It also has filters that automatically clean up the images so that it is crisp text on a white background.
Step 4: Sample Scan / Conclusion
I think that the quality of the scans are really good. (see the zoomed image) With the automatic filters that adjust the contrast, I find that the scans are far better than my flatbed. The images typically come in at around 2000 x 2700 px. And fast: I was able to scan a 500 page book in an hour and a half. Try that on a flatbed!
Caveat: My use case is for black and white documents. I have no idea how or if this would work as a color scanner.
- You can try other light sources. I might try LED strips (white) someday and experiment with placement.
- Instead of a cardboard box, you could make a box out of black fiberboard and gaffers tape.
- As mentioned in an earlier step, you could make plates for each document size that you plan to scan and devise an attachment system that affixes them to the tray.