IFD:PhysicalComp2011/Yunshui Jin: Difference between revisions

Revision as of 11:10, 26 May 2012

EHP - 3D Scaning Project

It's a project involved with 3D Scan.

Ideas And Thoughts

Generally,I showed the reason why we need 3D scan and also different manners to achieve 3D scan. I compared with these manners and choose David Laserscanner to be my platform. Compared with others, it is cheap(with free version and the professional version costs 291Euro while some cost almost 40,000Euro but offer the same quality), very fast(compared with photo-based method),high precision(While pointcloud-based technique can only offer a rather rough result ) and it can scan a large range of subjects from very large object to tiny small things if using the motor scanning.In conclusion, David system is almost the best choice.I would build a system to use the stepper motor controlling the laser to realize the 3D scan.

How To & My Process

Step 1 Material

Note: For the camera, In most cases, DAVID works in lowlight conditions to get a clear contrasted laser line. So the cam should be able to handle this. High light sensitivity and as little noise as possible is recommended. For the laser line, laser line should be as thin as possible –> focusable; as bright as possible; perfect straight line and a red or green laser if you use a color camera.

Step 2 Software Installation

Download the latest free David Laser Scanner in the David official site. Or open the local installation for David Laser Scanner V3.3. Find the documentation of the David software as well as many useful tips. Note: Limitation of the free David Laser Scanner is that the maximum resolution of the capture can be used by software is up to 640*480 even if the camera can capture with a HD resolution (1920*1200) , while the full license version can use as much as your camera can offer. 329 EUR for the full license and one can achieves super precise result with this reasonable price. David Laser Scanner is windows platform only. Step 3 Control A Stepper Motor With a stepper motor driver, we can let the movement of a stepper motor slower, smoother and quieter than controlling it with Arduino directly.

Find the Arduino code File:TestCode.zip. Note: 9V external power supply is necessary for driving a stepper. The USB power supply is not sufficient since it has a current limit. Do please turn off the power supply, if you want to exchange the connection of the 4 pins of the stepper. Or it may damage your circuit because it may generate an inverse voltage. Micro step can let the stepper slower and also quieter, but it is less accurate compared with a full step. With the easyDriver, you have options of 1/2, 1/4, 1/8 micro step. By default the easyDriver will drive a stepper with 1/8 micro step. And it can be altered by setting the MS1 and MS2 Pin High and Low. The documentation of easyDriver can be found and you can find the datasheet File:EasyDriverA3967 datasheet .pdf.

Code to Download

File:Code of Stepper(test).zip

@@ Line 55: / Line 55: @@
 [[File:laser_step3.png|600px|]]
-Find the Arduino code here.
+Find the Arduino code [[File:TestCode.zip| here]].
 Note: 9V external power supply is necessary for driving a stepper. The USB power supply is not sufficient since it has a current limit.
 Do please turn off the power supply, if you want to exchange the connection of the 4 pins of the stepper. Or it may damage your circuit because it may generate an inverse voltage.