Dead-band

stefan_o · Post by **stefan_o** » Thu May 15, 2008 7:43 am

I read on this forum that it is possible to get raw data from these devices, so i bought a pair of SpaceNavigators. I am using the HID interface to access them. The axis data I get is NOT raw! A dead-band has been applied to it. It is critical to my application that it get true raw sensor data!

How can I turn off the dead zone?

Post by **jwick** » Thu May 15, 2008 8:23 am

Hello stefan_o,

If you are using the HID interface, you are getting as raw data as the O/S can provide. We use the HID interface in our 3DxWare driver.

Make sure you don't have another driver installed. There are some "public domain" drivers floating around the internet that we don't in any way support or encourage.

What makes you think there is a dead-band being applied. The device is so sensitive that you should get some data if you blow on it <G>.

Jim
3Dx Software Development

stefan_o · Post by **stefan_o** » Sun May 18, 2008 11:22 pm

The only driver I have installed is 3Dx, but it has been uninstalled.

The dead-band is quite obvious;
1 / looking at the values
2 / if you let the device control the absolute position of the mouse pointer
3 / the device stops sending data when it is within the dead-band
4 / it can be measured on the vertical axis...

- push down the cap and rezero
- release it and wait until the value has settled
- rezero

- place weights (e.g. coins) on top of the cap until you get a small value
- let the value settle and note it as "WeightMinusDeadBand"
- remove the weights

- pull up the cap and rezero
- release it and wait until the value has settled
- note it as "A"

- place the same weights as last time on top of the cap
- let the value settle and note it as "B"

Weight = B - A
DeadBand = Weight - WeightMinusDeadBand

"DeadBand" will be about 12..14 on my devices, and this is only in one direction of the axis.

What is causing these lost levels?
Is it Microsofts HID-driver or is it your firmware (3.18)?

stefan_o · Post by **stefan_o** » Sun May 18, 2008 11:28 pm

the firmware version is 3.18

Post by **jwick** » Mon May 19, 2008 5:14 am

Your observations are correct. There is a very small deadband in the firmware to keep the device from sending data if it doesn't return to the exact center position because of internal mechanical friction. It can not be disabled. Chances are the device will never stop sending data if it doesn't have this deadband.

The device is not meant to be a laboratory instrument. It is meant to be used by the typical human hand in design activities.

Jim
3Dx Software Development

stefan_o · Post by **stefan_o** » Tue May 20, 2008 1:33 am

How about implementing a feature to disable it?

Post by **jwick** » Tue May 20, 2008 6:40 am

You can change the deadband in the firmware [only] with the SpaceNavigator for Notebooks.

stefan_o · Post by **stefan_o** » Wed May 21, 2008 6:54 am

Can it be turned off completely?
How is it done?
When will you add this feature to your other devices?

Post by **jwick** » Wed May 21, 2008 7:42 am

Can it be turned off completely?

Yes. Caveat emptor.

How is it done?

Through an HID packet that can be communicated to you privately.

When will you add this feature to your other devices?

It may be added to future devices. It will not be retrofitted to older devices like your SpaceNavigator.

This is an internal adjustment. We reserve the right to remove this feature at any time without any notice whatsoever. If you have a specific project, I suggest that you buy as many SpaceNavigator for Notebooks as you will need for now and in the future.