Tekscan FlexiForce ELF
(Economical Load and Force System)

The ELF is a very simple force measurement system consisting of electronics, a software package, one handle, and 3 FlexiForce model B201 variable resistance sensors (one in each force range of L, M, & H). The ELF hardware is simple to install, using a standard USB port. It can readily turn any computer into a force measurement instrument.

The ELF Software v4.3 is compatible with Windows 7, 8, 8.1, 10, XP, and Vista.

The ELF system exclusively utilizes Flexiforce sensors. These sensors have a patented interconnect to the ELF hardware. The combination of superior sensor performance, electronics and software insures optimal system accuracy and performance.

The Flexiforce sensor is an ultra-thin (0.008"), flexible printed circuit. The standard sensor is 0.55" (14 mm) wide and 9" (229 mm) in length, and can easily be customized. The system comes complete with three sensors in various force ranges: low (0 - 25 lb), medium (0 - 150 lb), and high (0 - 1000 lb). Variable gain capabilities of the ELF electronics enable the user to fine-tune the range; a force range of less than 20 grams up to 5000 lbs force can be covered with the extended list of sensor offerings. The software allows you to collect, record and play back data. The graphic displays available include: Strip Chart, Bar Graph, and a Digital Display.

ELF systems are easy to use and cost-effective for various tool and task analysis applications where force between the fingers and an object is to be measured. The products are also suited for return to work applications and job descriptions where actual job requirements need to be compared to the capabilities of a worker.

By adding additional handles, the user can view and record up to 16 channels of force data with FlexiForce single-point sensors.

Additional features include the ability to view 16 channels in one window, multi-point calibration routines, and the ability to tare a load.

ELF Software Features

The ELF software is a 32-bit application that is compatible with Microsoft Windows 7, 8, XP, and Vista. The software allows you to view a graphical representation of the force on the sensor in real time, record this information (as a "movie"), and review and analyze it later. There are a number of options for displaying the real time force data; it can be displayed as a strip chart, column graph, or digital readout. Recorded "movie" frames can be saved as ASCII files, which can be imported into a spreadsheet program, or opened in a text editor or word processing program. Eight different recording speeds are available from 8 Hz-200 Hz. Real time data or "movie" frames can also be copied to the Windows clipboard and pasted into other applications as a bitmap.

Typical ELF computer display

Standard features include:

  • Software Controlled Force Ranges
  • Real-Time Display
  • File Storage
  • Data Retrieval and Playback
  • Graphic Displays
  • On-Screen Help
  • ASCII Output

Advanced Optional Software Features

More advanced features are available upon request. These include:

  • High Speed Data Acquisition: five different speeds from 8 Hz-5760 Hz

Physical Properties

  • Thickness: 0.008" (0.208 mm)
  • Length: 9.000" (228.6 mm) End-to-end
  • Width: 0.55" (14 mm)
  • Active sensing area: 0.375" (9.53 mm) Diameter
  • Connector: Custom interface to ELF Data Acquisition System

Recommended Maximum Force

Adjustable gain feature of the ELF System allows the customer to set force ranges.

Sensor Max. Force (High Gain) Max. Force (Low Gain)
B201 - L 0 - 1 lb. (4.4 N) 0 - 25 lb. (111 N)
B201 - M 0 - 25 lb. (111 N) 0 - 150 lb. (667 N)
B201 - H 0 - 150 lb. (667 N) 1 - 1,000 lb. (4448 N)

Typical Performance

  • Linearity (Error): < ±3% (Line drawn from 0 to 50% load)
  • Repeatability: < ±2.5% of Full Scale (Conditioned Sensor, 80% of Full Force Applied)
  • Hysteresis: < 4.5 % of Full Scale (Conditioned Sensor, 80% of Full Force Applied)
  • Drift: < 5% / logarithmic time (Constant Load - 25 lb.)
  • Response Time: < 20 µsec (Impact load - recorded on Oscilloscope)
  • Operating Temperature: 15°F - 140°F (-9°C - 60°C)*
* Force reading change per degree of temperature change =±0.2%/°F (0.36%/°C). For loads less than 10 lb., the operating temperature can be increased to 165°F (74°C).

ELF Data Acquisition Electronics

Handle electronics schematic

Residing within the plastic ELF handle is the data acquisition hardware. This patented interface ensures optimal performance of our FlexiForce sensors. The simple insertion of a FlexiForce sensor yields a powerful measurement tool.

The patented electronics allow the user to optimize the performance of the ELF system over a selected force/load range. The electronics adjust the device sensitivity to best fit the dynamic range of the specific application. This allows the user to "fine tune" our single element sensors for optimal performance. Designed to be user friendly, simple calibration procedures can deliver accuracies of ±5%. More controlled procedures can reach an accuracy level of ±3%. The ELF's innovative electronics provide high quality signals at distances of up to 30 feet from the PC.

FlexiForce is a trademark of Tekscan, Inc.