This page explains how to use the haptic device in our 3D facility for Interactive Molecular Dynamics. Please read all of the instructions carefully!

Basic instructions

1. Add the following lines to the file .vmdsensors in your home directory:

     device phantombuttons vrpnbuttons://portland/Phantom0
     device phantomfeedback vrpnfeedback://portland/Phantom0
     maxforce 4
     device phantomtracker vrpntracker://portland/Phantom0
     scale 10
     rot left 0 0 -1 0 1 0 1 0 0
   

   This tells VMD how to use the haptic device.
2. Start VMD on cancun and run an IMD simulation. See the IMD page for help with IMD.
3. Make sure the haptic device is plugged in to power and data and that its indicator LED is glowing orange. If the haptic is not plugged in, see the section Power-on and calibration below.
4. Rest the haptic pointer in its neutral position (centered, on the table, pointing forward).
5. Run the phan_server executable located in the directory C:\sti on the windows laptop (portland) next to cancun. Usually, you can just press <enter>, because that file is already selected. After a while, the indicator on the haptic device will turn green and you will hear some sound.
6. Open up the Tools->Tracker menu in VMD and click "Create Tool", then set the "Tool type" to "tug". ("Spring" is another useful tool for IMD; see the vmd manual for more information.)
7. Select each of the phantom devices, one at a time, from the "Add device" menu. The haptic pointer should now be on the screen. If it seems to have a strange position or orientation, see Power-on and calibration below.
8. Adjust the force scaling (a spring constant in units of kcal/mol/A²) to a reasonable level, usually at least 10 or 20.
9. Interact with your simulation.
10. When you are done, turn off the haptic device by closing the phan_server window. The LED should turn orange again. This is very important because the motors in the haptic device are continually straining as long as it is on. Please let it have a break!

Power-on and calibration

1. First of all, never plug in the large data cable while the power to the haptic is on. Spurious data signals could cause a powered-up haptic to make random and destructive motions. Instead, unplug the black power cord first and then connect the data cable.
2. Plug in the black power cord.
3. Start the program Phantom test located in the directory

     C:\Program Files\SensAble\PHANTOM Device Drivers
   

   to see the state of the haptic device.
4. If the picture on the screen corresponds well to the actual location or orientation of the haptic device, you are done. Otherwise, try the following steps in a random order until it looks right:
   • Turn off the Phantom test program.
   • Turn on the Phantom test program.
   • Unplug the black power cord from the haptic.
   • Plug the black power cord into the haptic.

Other problems