Velocomputer bike smartphone computerVelocomputer just announced a new mobile app in conjunction with the SmartSensor 4 bluetooth device for tracking cycling performance. Measuring time, distance, speed, acceleration, cadence and slope grade, Velocomputer makes the claim it’s 360 times more accurate than other cycling sensors.

The waterproof Smartsensor 4 body sits on the chain stay and is wired to a magnetic field sensor beside the rear hub. As a magnet on the wheel spins, data is collected and streams to a bar mounted smartphone (either Android or iPhone 4s) via bluetooth. They claim it’s great for all disciplines of cycling. Measurements are roughly 1.5 inches high and long, 0.5 inches deep.

Right now, they’re offering an early bird pricing of $100 the first 100 sensors sold. Retail is $200 after. Get the full details at VeloComputer or SoundofMotion. Click ‘more’ for a screenshot and specs…

Velocomputer SmartSensor 4 Android Iphone App

  • Detects 1cm ( ~ 3/8″ ) of distance on a standard 700C wheel.
  • At least 360 times more accurate than traditional cycling sensors
  • 1 second latency, up to 7 times faster than a traditional cycling computer
  • Built-in 3-axis accelerometer
  • Measures data with precision:
    – time in 0.001 of a second
    – distance in 0.01 of a meter
    – speed in 0.01 of a kilometer (KMH) or a mile (MPH) per hour
    – acceleration in 0.01 of a KMH or a MPH per second
    – cadence as low as 1 rotation per minute (RPM)
    – slope grade in 1% increments
    3-axis X, Y and Z G-forces
  • Bluetooth 4.0 SMART (low energy)
  • Replaceable 3 volt CR2032 coin cell battery
  • Rigid plastic enclosure
  • Waterproof


  1. Am I missing something?

    The Edge 500 is only $50 more.

    If I felt like using a head unit I couldn’t read in the sun I’d probably just use a free ap.

  2. looking on their facebook page I see this (looks like I might be getting one):
    (Now if only samsung galaxy S3 would issue a fix for the bluetooth 4.0 problems)…

    David Bermingham Hi, just wondering how accurate the power data is in comparison to the more “traditional” crank power meters like Quarq etc? Thanks
    7 hours ago · Like

    SoundOfMotion (VeloComputer) Hi David Bermingham, when comparing to “traditional” crank or hub power meters you will have 2 different data sets. Crank or hub power meters provides you with applied/input power whereas the VeloComputer provides you with propulsion/output power. If you have both systems you can see the “economy/efficiency” of the ride, and analyse how much power you loose between input and output. If you use the VeloComputer by itself it still provides very high accuracy because of the 1 degree precision. I hope that answered your question?

  3. It’s power calculation has to be less accurate than iBike’s because at least iBike has a process for calculating coefficients for aero drag and for rolling resistance. Further it’s certainly questionable whether such high precision measurements are even useful

  4. I would like to get the sensor if it would make my Garmin more accurate, but it doesn’t have the ANT sport wireless protocol.

  5. This is just useless. Why do we need this level of accuracy? I want to know how many km i have gone, not how many mm.

    And the power thing? Cycling is all about aerodynamic, and that’s not even taken into consideration.

  6. It doesn’t sound like cadence is measured directly; it sounds to me like cadence is somehow extrapolated from the wheel speed. When’s the Android app gonna be available?

  7. I have been looking closely at this.
    The unit body itself contains the cadence sensor and the wheel sensor is at the end of the cable. So two separate magnets are used including the cadence one on the crank.

What do you think?