Out of the box

The VHand and all of its accessories are conveniently packaged in a small plastic handle-case incorporating shaped foam that fits each element. The first impression when opening the case is that while this product does not cost much, it feels professionally made. In the following sections we will see in more details how the glove actually performed.

Installation

Highlights:

• About 15 minutes total
• The installation process was easy
• The installation application GUI should use the standard Microsoft install shield look and feel.

The installation process is relatively easy. The only thing that could be improved is the installation shield interface. While visually pleasant, the provided installation shield is not completely following the standard Windows install shield design rules. This can be an inconvenience for some users. Once the installation was started, it completed without any problems.

Calibration

Calibrating the glove using the glove configuration software is not as easy as we could expect. Due to its inner working nature, the glove fingers flexions are not tracked as precisely as with optical fiber based gloves for instance. This remembered us of calibrating a computer joystick, which can often be a bit of a trial and error calibration process. So to sum up, you can expect some tweaking before you get the perfect result, but it was not too much of an issue in our tests and we managed to get a decent calibration to work within a reasonable amount of time.

One thing that disappointed us was that there is no software method to adjust the raw data values sent by the glove controller for each finger. For example, in our sample unit, all finger returns values of about 100 to 200 when the hand is fully open, standing on a flat surface. When the hand is fully closed, the little, ring and middle fingers return close to 1023, but the index and thumb end at about 500 of the 1023 full range value. As we will see later on, this can cause some design problems for users coding their own application using the provided SDK. To counter this problem, they provide an alternate numerical scale to represent finger flexion using normalized values from 0 to 100 (percentage of full flexion). These values are calibrated using the provided configuration tool so that different raw data ranges can be correctly fitted on the 0-100 range for each finger. While this worked reasonably well, we ended up using the raw data instead inside our code as there were issues calibrating the conversion between the two value domains.

Operation

• The glove fits well on the hand and is quite comfortable to wear.
• The small ribbon cable that goes inside the glove and connects to each finger sensor looks relatively fragile so the user should take special precautions when putting the glove on and off.
• All the fingers give a fast response to user's movements.
• The detected flexion dynamic range varies quite a bit between fingers.
• The unit cable, linking the wrist box to the host computer serial port, is too short. only 4 feet.
• While the included demo applications are nice, they do not really show the real potential of the glove, especially in markets like virtual reality.
• We noted conflicts between the VHand software driver and other Windows applications.
• Maximum measured update rate was around 32 Hz.

During our tests, we noted that the amount of flexion detected varies quite a bit between fingers. Looking at how the glove is made, we can note that some bending sensor bands are not covering the same amount of finger length. By nature, all fingers have a different length as well so it adds to this situation. Depending on how the glove is calibrated at the manufacture, it may also affect the end result sensitivity of each finger.

While testing, we noted conflicts between the VHand software driver and other Windows applications. Unfortunately, we were not able to repeatedly reproduce this behaviour or identify the origin of problem. From our observations, it could be related with the method they are using to access the serial port data. The manufacturer is aware of this and is working on an updated driver.

During our tests, we measured a maximal update rate of about 32 Hz using the sample code provided by the manufacturer as well as our own in-house tests. More information will follow on this in the next sections.

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