Intro: Make a 3D Scanner From a Cell Phone and Bicycle Wheel
How to make a functioning 3D scanner rig from a cell phone and a bicycle wheel. That probably sounds a little preposterous, how can you make something as complicated and advanced as a 3D-scanner from something as common as a cell phone and as archaic as a wheel?
This is how: most 3D scanners utilize a system of lasers and cameras to scan all points of an object into a computer. These systems are very complicated and rather expensive; however, there is a much cheaper way to accomplish much the same thing without lasers.
This scanner utilizes the Free 123D Catch Software supplied by Autodesk. it takes a series of still photos of an object and stitches them together into a 3D model that can then be printed either in your own home, or through a website such as Shapeways.
With 3D printing technology developing so quickly (some are calling it the New Industrial Revolution), soon everyone will have the ability to print digital objects themselves; however, not everyone has the required skills to accurately produce a 3D model, especially if you are making something that interacts with real world objects ( eg. phone cases).
This is were a 3d Scanner comes in, it allows anyone to create a relatively detailed model that can then be modified and adapted to suit your needs.
My design utilizes the hub and rim of a bicycle wheel, in my case a 26" mountain bike wheel, to have two rotating pieces that can rotate around each other. The middle piece, the stage, can either be rotated or left stationary. While the camera and its stand, the "Trunk", can be rotated around the stage while the camera takes pictures. The scanner is designed to be very easy to take apart, and not damage either the bicycle wheel or the phone. Cell phone cameras work great for this (better than a DSLR), because of how short the lens is, this allows the camera to focus very tight, it is also lighter and probably cheaper.
It then makes use of the 123D Catch software to stitch the images together into a 3D model that can then be used either with digital fabrication, or design and animation(please leave a comment if you would like me to make an instructable to this affect). You can also use this system to display artwork in a rather unique way.
Step 1: Safety (and Other Legal Stuff)
This project involves working with hot molten plastic therefore there is a risk for burns.
This project also uses sharp tools that can cause cuts or other injuries.
I am not responsible if you hurt yourself or others while completing this project.
I am also not responsible if you destroy your phone or bike wheel, although if you follow my steps there should be none of that.
I did not create the 123D software or any of the videos that describe its use. I include them in this tutorial to help others replicate my project.
This is published under a creative commons license so I don't mind if you modify and improve upon this design, actually I encourage it, but please source me as you inspiration or something to that effect. Also it would be great if you could share it in the comments section.
Now that that is out of the way lets continue with the project.
Step 2: Materials and Tools
This project involves a lot of different materials and a few different tools,with that said it can easily be completed using only hand tools. I will list them all here, but go into more details and specifics of each during the step that they are involved in.
Hand Saw (Wood)
Hand Drill (or Electric)
Drill Bit Set
3/4" Drill Bit
Coping Saw (Or Jig Saw)
Pot (The kind you cook things in:)
Heat Gun (or electric stove, or propane heater, basically something that gets really hot without flames)
Ruler or Tape-Measure
Pencil or Pen
Gloves (Thick/Heat Resistant)
Bicycle wheel (Preferably Cassette not Freewheel, don't know the difference? CLICK HERE)
Cell Phone (Needs a Camera)
Old Pair of Headphones
Old Cell Charger (That Fits Current Phone)
Hand Moldable Plastic (Can Be Ordered From HERE. 1/2 pound bag will be plenty)
Plywood ( Two 2' x 2' squares)
PVC pipe ( about 2' long, mine was 3" OD)
A few nails ( About Four 1.5" in Length)
(Literally) A Few Nuts and Bolts (About SIX Bolts That Are Around 1.5" long and SEVEN Nuts to Fit)
So that is what mine was made of. This is only a prototype and I hope to have a set of 3D printable files soon to replace the hand moldable plastic, so stay tuned for that if you have the ability to 3D print objects. If not the hand moldable plastic is a great substitute, although it's harder to replicate the same results, but who knows yours might be better.
Step 3: Size the Plywood
We want the plywood to be in two 24" by 24" pieces. (Unfortunately I didn't have a large enough piece of plywood for that so I have a few stabilizing pieces on the bottom.)
Find the center of one of the pieces and bore a 3/4" hole there. This should accommodate the bottom of the hub.
//side note If you ever see a hand drill at a garage sale or something I would recommend getting one,they //offer you much more control and never need to be plugged in.
Remove the axle from the hub pay attention to the orientation of the springs.As you will probably need to resemble the wheel later on.
Place the wheel into the hole, it should spin freely.
Add a few longer rods to the bottom piece for added stability. Drill pilot holes or the wood will most likely split.
The corners on the top piece (stage) will need to be rounded. Measure the radius of the bicycle wheel and use a piece of string or the tape measure to draw a circle on the top piece. You would think that the radius of a 26" rim would be 13.5", but it isn't. Use a coping saw to cut the corners but don't sand it yet, as there will probably be some sizing issues later on as we add the trunk, and other pieces.
Step 4: Attach Hub to Stage
Using the hand moldable plastic I molded a piece that would fit over the free hub and attach to the bottom of the stage. Working with this is about the same as working with play doh or sugru, except that it cools down in about two minuets and becomes solid. As this is not a very precise material there isn't a lot of description to give you in terms of exact measurements and such, but the pictures should demonstrate what I'm trying to get across.
The plastic pellets need to be heated in (not quite) boiling water to become soft enough to be malleable. Once the pot develops little bubbles on the bottom the water is hot enough to melt the plastic. Watch out because the plastic will be hot, it won't burn you, but be careful anyway. Scissors work well at cutting the plastic, just make sure the scissors are wet otherwise the plastic will stick.(pics 2-6)
Put a small amount of olive oil on the free hub so that the plastic won't stick to it. Then wrap it in a layer of the hand moldable plastic.(pics 1, 7 and 8)
Create a sheet about 4" square and attach it to the top of the piece you just created. Just soften the top of the previous piece otherwise the ridges that line up with the free hub will get skewed and you will have to start over (this happened to me). If you want you can then stick the plastic to the bottom of the stage, make sure it's centered. The adhesiveness of the plastic isn't strong enough to hold the piece onto the stage for long, but it should stick for a little while.(pics 13-17)
Drill four holes in the top sheet and the stage and attach them permanently with nuts and bolts.(pics 18-20)
The stage should now spin freely on top of the wheel.
/* Side note on the hand moldable plastic. This is a great material for rapid prototyping. While 3D printers are becoming much more affordable, they are still a little beyond the reach of many, including myself. Websites like Shapeways offer a nice way for those who don't own a 3D printer to create things with them, especially models that can only be created using that method, however once you factor in shipping time and costs (If you don't live in the US of A that is) it really ceases to be rapid prototyping. The hand moldabe plastic is a great alternative,while it is not nearly as precise as a 3D printer, it can accomplish many of the same things a lot faster and sometimes a lot cheaper.*/
p.s If you have a laser cutter or some fine woodworking skills you could
simplify this step by flipping the wheel upside down and placing the grooves of the hub into a specially designed cutout in the base. Then you could attach the stage by screwing it into the holes that normally accommodate a disk brake.
Step 5: Create the Trunk
The "Trunk" is the name I am giving to the curved piece of pvc that holds the phone at a specific distance and height from the object. It attaches to the rim of the wheel at the point were the shrader (or presta) valve goes through the rim.
Start by cutting a strip out of the PVC pipe. I used a Dremel for this, but you could use a hacksaw, or even a wood saw. Cut the pipe to length first and then cut a strip out of it, that way you won't need to make a plunge cut in the middle of the pipe, the way I did.
Starting from the center, drill a hole (the same diameter as the nails you are using) in the center of the pipe and proceed to drill another every 3 inches as you go "up". Drill another hole (the same radius as the bolts you are using) near the bottom of the PVC. So there should be a series of holes on the top half, but only one on the bottom half.
Plug in the heat gun and place the PVC near the hot end. Once PVC gets warm it becomes malleable and retains the shape you give it. Use gloves because the pvc gets hot, it doesn't conduct heat but the area that you will need to bend will be to hot to handle with bare hands. Also ware safety glasses because if you ever open you eyes above where the heat is it will be very uncomfortable.
Starting from the center give the PVC a gradual curve "inwards" (towards what would be the inside of the tube). The radius of curve will set the maximum height of any object you wish to scan.
At the bottom we want the PVC to match the curvature of the bicycle wheel, both the radius of the wheel, and the curve were the tire fits into the rim(I hope that description isn't too confusing). Heat it up and squeeze it in a vice, this will mostly flatten it, leaving it with about the same amount of curve as the rim. The other curve of the rim can also be modeled into the pvc, I would recommend using pliers to bend this part because it is so tight a curve that doing it with you hands is too much work.
Use a nut and bolt to secure the trunk to the rim. Put it through the hole in the rim that is meant for the valve. You will see two parallel spokes at this point in the wheel.
It should be tight enough that the "Trunk" stands up strait.
If you don't have a heat gun you can also heat it up over an electric stove or propane heater, just make sure you don't scorch the pvc.
Step 6: Attach Phone to Trunk
Again I used the hand moladable plastic to make a piece that will hold my phone on the "Trunk". It is secured on one end by a headphone jack and on the other by a mini usb connector from an old phone charger. The two pieces are tightened with a bolt. The other piece connects to this same bolt and uses another nut to secure it. This step is going to be a little different for every phone, but the same kind of system will work on most phones. As long as your headphone jack and charging port are on opposite ends of the phone.
Start by cutting the wire of the old headphones and old charger, or buy one of those cheap airport multichargers with a bunch of different adapters, that way you don't need to completely sacrifice a charger (this is what I did).
Next model a piece that wraps around the headphone jack and extends just less than halfway down the phone before making a right turn outwards from the phone.
Repeat the same steps to make a piece that connects to the charger.
I used these methods so that the molten plastic would never touch my phone, it would be bad to have it stick. You could avoid the charger earbud issue by more closely following the contours of you specific phone, but I wanted this to be as universal as possible.
The next part is to make holes in both of the upturned ends. I found the
best way to do this is to push the bolt through the plastic, which will create a thin "bubble" of plastic around the bolt, and then cut around the bottom of the bolt with scissors.
Next use all those long lost kindergarten skills to roll out a long narrow piece of plastic, wrap this around the PVC, either get the PVC wet or coat it in olive oil to avoid sticking. Make sure it is wide enough to move up and down the PVC Trunk.
The next piece connects to the tube wrapped around the PVC and then extends out and connects to the bolt that attaches the two pieces that hold the phone up. Roll out another tube of plastic and flatten one end.Using the method described above punch a hole the same size as the bolt in this flattened end. Then connect the other end to the ring around the PVC, melt both pieces a little to ensure a solid connection.
The phone should now be able to slide up and down the trunk. Use a nail as a pin and put it through the holes in the truck to limit the descent of the phone.
Once the trunk is attached to the wheel again you will have a working rig, but there are a few things we still need to do to make sure it works well.
// The phone holder .stl and inventor .ipt is attached to this step. It is based of the dimensions of my Nexus 5 so it should accommodate most phones. The piece that connects the phone holder to the trunk is also included. Please note I have not 3D printed these (yet. wink wink nudge nudge) so it would be awesome if anyone does print these to upload a picture and any refinements that I should make in the comments.
Step 7: Refinement
To make getting a good scan easier it is recommended to place your model on newspaper or a similar matte textured material. Bland backgrounds or backgrounds with repeating patters don't work as well. So I covered the stage in some old printouts, glued and stapled it down.
You will also need to add a counterbalance opposite the Trunk. I just placed a scrap piece of wood on top of the rim. you could zip tie it down or something, but it really doesn't need to be.
Another thing you might want to do it tie a string to one end of the stage, the other end will either be nailed to the ground, if your working outside, or tied to a heavy object. This means that you won't have to hold the stage when you are using the scanner.
Step 8: Use
So how does this contraption work?
This scanner utilizes technology supplied by Autodesk for free to anyone connected to the internet. The software you need can be either run off your browser or installed on your machine, I recommend installing as you get more options, there is also an app but I have not used it. You can find it at the 123D Catch webpagelocated here.
This video by Autodesk describes the processes of capturing a 3D model using this technology, I recommend watching it as it explains it much better than I can. As you can probably see this rig will speed up this process a lot. The holes on the trunk set the angle of the camera, so you can take multiple passes at different angles if you need too. The wheel spins the camera around the object at a constant distance from the object.
There are a couple of different ways to use this. I am currently experimenting to see which works best.
First way is to have the object centered on the stage and to the spin the stage while leaving the camera stationary. This way is a little easier, but based on the video above it is not the recommended procedure, as the software could struggle with the resulting change in shadows.
Second way, the way this rig was designed to be used, is to once again center the object on the stage, but this time hold the stage still and spin the camera around the object. You can either take a video and use the techniques described below to convert the video to a series of stills. Or you can take a picture about every 20 degrees as you rotate around the object.
If you go the video rout and have some of the Adobe suit installed (or you can try this free software that accomplishes the same thing) you will greatly speed up the processes of scanning objects, and you will never have to worry about not taking enough pictures.
- To do this in flash first create a new as2 or as3 document. Then go to File--> Import --> Import Video. Select your video and make sure you have the embed in timeline option selected. Then click finish.
- You should now be able to scrub your video by moving the play-head along the timeline, if you just have a box in the middle of the screen and only one frame then you probably didn't have embed in timeline selected.
- Then navigate to File--> Export--> Export Video. From the save as dialogue box select the jpeg sequence file type. Make sure you select a new folder for this because it will generate a lot of files. Hit save.
- Now there should be a ton of files in the new folder. Select every tenth, twentieth, or fiftieth file(depends how fast your camera was spinning around the object) and upload them to 123D Catch. You should only have about 20 files per pass; however, I think you can select as many as you want, it will just take longer to stitch together 300 files.
If you don't have any adobe products and don't wan to download the free software (I don't blame you). You can still use the video method.
- Open your video in any movie player you wish and then take a screen shot (PrtScrn button on your keyboard).
- Open your favorite photo editing software(GIMP is good and its free) and make a new file the same size as your screen resolution.
- Crop out the video player so that you have a clear view of the object you are scanning, save this screen shot as a jpeg.
- Repeat every time your object rotates about twenty degrees, you should end with about 20 files.
- This doesn't take as long as you think, once you do it a few times you will memorize the pattern and will go pretty quickly.
Then upload the images to catch and press the create capture button. Depending on how many files you uploaded it can be anywhere from 5min to a couple of hours to stitch all the images together. You should then be able to download your newly created model and do with it as you please.
Step 9: Conclusion
I would like to thank you for reading this. All comments and Votes are greatly appreciated and I would love to see what the community can do with this technology.
I will be updating this step with upcoming CAD files that can be 3D printed and used instead of the hand moldable plastic.
I will also be adding models that I create with this scanner as I create them. I will experiment with different techniques and upload different results and update this Instructable as needs be.
I also have a lot more pictures than I uploaded to the site, so if you would like clarification of something, please leave a comment.