The MotionWatch 8 with a tri-axial digital accelerometer

The MotionWatch 8 is the next generation of actigraph from CamNtech, inventors of the Actiwatch. CamNtech has utilised advances in accelerometer technology to produce the MotionWatch 8 with a tri-axial digital accelerometer.

The activity plots coupled with specialised software serve to quantify the intensity and duration of daily physical activity as an indicator of a particular lifestyle or to monitor the effects on mobility of a medical condition as well as the efficacy of treatment for that condition.



  • Size mm: 36(l) x 28.2(w) x 9.4(d) excluding strap
  • Weight: 9.1 grams (including battery, excluding strap)
  • Sensor: Tri-axial, MEMs technology. 0.01g to 8g range, 3 – 11Hz
  • Battery: CR2032 Lithium Coin Cell
  • Battery Life: 6 months run time; simple user change
  • Memory: 4Mbits non-volatile (182 days recording @ 1min epoch AW mode uncompressed)
  • Waterproof: 3 Bar (suitable for swimming)
  • Marker button: Yes – with visual feedback
  • Epoch: 2, 5, 15, 30, 60 secs in AW compatible mode
  • Comms: Direct USB, uses generic Windows drivers, Micro USB cable.
  • Download: All data in 50 secs approx.
  • Strap: Bespoke XL 12mm silicone (245mm overall length) or 12mm nylon
  • Integral Light Sensor
  • Type: Digital – human eye response optimised.
  • Range: Automatic ranging; 0 to 64000lux
  • Resolution: 0.25lux (0-1000 lux range)
  • Sampling: 1 sample per second – averaged over epoch



 Previous Actiwatch models required a reader to communicate telemetrically between the Actiwatch and PC.

However the MotionWatch 8 features an onboard Micro-B USB port allowing direct connection between the host PC and MotionWatch.

This offers two distinct advantages; communication speed – all data can be downloaded within 50 seconds, and cost; now there is no longer a need for an additional reader unit.

pdfMotionWatch 8 Overview

pdfMotionWatch 8 User Guide


The MotionWatch has been validated against polysomnography; initial details were presented at ESRS 2012:
Validation of a new Actigraph MotionWatch versus Polysomnography on 70 healthy and suspected sleep disordered subjects.

There will be a more detailed publication of this comparison to follow.



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