Grip Force

Out of stock

Force Fiber Optic Response Pad used in fMRI and MEG computer research tasks

For the 932 and Birch interfaces

All plastic construction


Current Designs' fMRI grip force is the perfect choice for a wide range of computer response tasks used in the human brain mapping project. It is non-magnetic, non-electronic, and entirely made out of plastic, so will not add noise to the images or raise safety concerns in the MR/MEG room or similarly demanding environments. There is a less expensive, non-MR trainer available for this response pad for use outside the magnet room.


  • Handheld for the FIU-932 and Birch interfaces
  • Machined black enclosure with protruding force bar which moves in when gripped to produce a roughly linear force measurement output based on the pressure applied, with a range of 25N, 50N, 75N, 100N, 300N, or 500N (specified at time of order)
  • If a different maximum force is desired, please email
  • Wide variety of outputs available for Windows, Mac and Linux computers, including several USB and Serial modes
  • Force grip: 7 x 1.25 in. (17.8 x 3.2 cm)
  • Force bar: 5 x 0.5 in. (12.7 x 1.3 cm), 1 in. (2.5 cm) out from main enclosure; maximum travel is 0.05 in. (0.127 cm)
  • 10 ft (3 m) long fiber pigtailed connector
  • Active light levels for handheld identification and gain adjustment

Spring recommendation

We recommend the 100N spring. Some customers choose the 500N spring as a safe high number to cover strong users. But this choice means that much of the signal range is not used except for the rather extreme high force cases. We have found that 100N covers most cases well and uses the signal range more effectively. (On the low end the mechanical stiction of the moving part can affect the smoothness of the movement, so we recommend using springs below 100N only if your study demands that specifically.)

Signal and Range notes

The maximum force is set approximately by the springs you choose. These are set by design but are not individually measured and the actual full scale force may vary by 10% or more. And the internal sensor is not perfectly linear with force. So for these two reasons it is important to perform force calibrations under real use conditions if highly accurate force measurements are needed.

What Else Is Needed

This handheld response device needs an electronic interface to convert the optical signals to standard computer interfacing signals. In most cases you will also need a long optical fiber extension bundle to allow this device to be used at a distance from the interface unit. The required interface and compatible bundles are shown below in the Related Products section.


magnet safe This item contains no metal, nothing electronic, and nothing magnetic. It can be used safely in the magnet room.
More Information
Price $2,800.00
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