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I am quite new into the electronic realm, so forgive my lack of proper terminology.

I am planning to build a simple device, that I will be use to manipulate a mesh on my computer. when I move the device, the mesh rotate/translate. As example, you can use one of these artist doll/mannequin used in art class, or just a hand; the concept is applicable to various uses.

For sake of clarity, let's use a human hand/glove.

So, I was looking into it, and found that I need to use a gyro (which records the rotation among the 3 axis), and an accelerometer (which would give me the variation in position, altho some says that it tells me the axis orientation relative to the ground, thanks to the gravity field).

Now, if you want to make a glove, you would end up with one gyro on the back of the hand (the hand always rotate as whole on the wrist axis), and 5 accelerometer, one per finger.

Is there another technique to have the same result, but without this waste of sensors? I've seen electric strips, which are basically variable resistors that change their value as they get curved in one direction, but the price is close to a sensor, and they offer very unstable signals, which would require a lot of compensation via software.

is there any other way, other than use a camera or the aforementioned gyro + accelerometer; to monitor the variation of position of an object? In the case of the hand, you would be interested only in variation from the starting point (say you want to make an animation of a hand that open and close), I can't really find a way to do it unless I use all these sensors.

Any help is more than welcome...I don't even know what to look for, to be honest, so I rely on your expertise. Thanks in advance.

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2 Answers 2

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Building a "power glove" or a video tracking system from scratch is definitely not a project for a beginner.

However, there are many commercial devices out there for fairly reasonable prices — mainly aimed at video game users — and your best bet would be to acquire one of them and learn how to work with it in software.

One particularly good example is the Xbox Kinect. There is a software library that allows an application developer to access most of the features and capabilities of this 3D video sensor, including sensing the position and pose (e.g., hand position) of one or more human beings.

After you have your software application working at some level, you can revisit the question of building (or buying) a better user interface for it. At that point, you'll have a much better idea of what you really need in terms of the technical details.

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  • \$\begingroup\$ Thanks for the reply; indeed I know that it is not a starter project, but I want to spend time learning something that may be applied to my project, instead than making the usual fm radio, or other simple kit that you can buy online. BTW I am not aiming at making a controller; I work as 3d artist, and I am exploring new ways to manipulate objects in 3d....I've tried 3d mouse and they are useful, but I wish to be able to move an object in real world, and translate it to the virtual world (kinda like stop motion artists do, but in real time). \$\endgroup\$
    – rataplan
    Commented Dec 12, 2013 at 8:40
  • \$\begingroup\$ Buying one item is not feasible, since they cost thousands...6 sensors cost me 100 and I just have to spend time writing the code :) The kinect is an option, since there are drivers ready and easy to find, but it has some problems with tracking, especially if you are too close or too far; it is an ancient technology based on cameras; now it seems that the mocap industry standard is based on smart sensors, abandoning the mechanical sensors (like the old metal frames). \$\endgroup\$
    – rataplan
    Commented Dec 12, 2013 at 8:43
  • \$\begingroup\$ I totally get your point, I am going beyond my skill, but it is to learn after all. got good part of the software done too (found plenty of examples online, luckily). I just need to figure out what I have to use; the input at that point is irrelevant, because I can feed the program the raw data independently from where they came from: analog or digital. Thanks again for your precious suggestion! \$\endgroup\$
    – rataplan
    Commented Dec 12, 2013 at 8:45
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To track movement in space, you can use ultrasonic tech like the MagicMouse http://www.gizmag.com/go/7293/ I have not tried it, but I am betting you could get a fairly good 3d position with three appropriately placed ultrasonic distance sensors, eliminating the need for special electronics on the hand.

To track fingers bending, I can't see a way to avoid a flex sensor, but would not expect them to cost nearly as much as an accelerometer. Here's an article on making flex sensors cheaply: m.instructables.com/id/DIY-Bend-Sensor-Using-only-Velostat-and-Masking-T/

Hope this helps.

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  • \$\begingroup\$ Thanks for the reply. So there is also the possibility to use ultrasonic sensors; alto you need receivers that map the area that you wish to use. The problem thou is that it would cover X and Y, but can also cover the Z axis? Interesting alternative, altho I see that it takes quite a lot of sensors to track all 5 fingers. I have found accelerometers for $14, and bend sensor for 12...as you can see the difference is irrelevant. I will take a look at that link, thanks!!! \$\endgroup\$
    – rataplan
    Commented Dec 12, 2013 at 8:36

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