Archive for the ‘magnetism’ Category

Magnetometers: iPhone has Apps for this (…as well as other sensors)

Thursday, February 28th, 2013

Following-up from my previous look at magnetometers

I have an iPhone 4 (ordinaire) running iOS 4.  Apparently it has a magnetometer, and a number of Apps to alarm, display and log data from it are available.  Hey, it’s getting towards being a “Tricorder” (of Star Trek fame)…

The ones I have tried are:

  • MAD – Magnetic Anomaly Detector
    • When I run it, I tend to click (enable) all three buttons (they each display their current mode, not switch effect).
    • If I’m simply in a room, I tend to drop the threshold (slider) to half or a quarter.  Otherwise if driving I leave it Full.
    • The Log is simply a text-pane, one can Select/Copy etc; unfortunately the log gets cleared when you exit the app.
  •  EMF Detector
    • Has an “analog meter” style of display and audio tone (optional, volume-controllable).
    • Maybe useful for tracing wires etc.?  But how reliable?  In my house it ignored a light-switch and around it but “got excited” over certain parts of window frames and metal radiators (certain corners only) for reasons I don’t understand.
  • XSensor
    • Displays and optionally logs/emails data from several of the sensors on iPhone: Magnetics, Accelerations, GPS, Gyros.
    • Fun for finding out about the sensors, their capabilities, their noise-issues etc.
  • Accelerometer Data (“ordinaire” or Pro)
    • Data can be raw or Low-Pass filtered (for absolute gravity and orientation) or High-Pass (monitoring for their changes).
    • Accelerometer data can be streamed (via UDP) to computer or logged to CSV file.
    • The Pro version saves to Flash, instead of just RAM, hence greater logging capacity.
  • Sensor Kinetics
    • Plain sensors: Accelerometer, Gyroscope, Magnetometer
    • Derived sensors: Linear Acceleration, Gravity, Attitude.
    • Nice graphics (clarity as well as entertainment value)
  • ?

Suppliers of Beautiful & Strong Magnets

Friday, February 22nd, 2013

A brief search, starting with Amazon, revealed these: