Member #139104

Member Since: June 20, 2010

Country: United States

  • I discovered this particular version to be totally useless within a new school building where it was to be used. It it terribly susceptible to electrical noise in a modern building. I eventually bought three thinking I had a dud after buying the first one. The device worked perfectly at home where I developed at least four different physical designs and countless software tricks trying to discover and mitigate the problem. In the final attempt the sensor and Arduino controlling it were next to each other all within a metal enclosure.

    I rolled the device in its finished form on a cart through the new building to observe its behavior. In one remote egress stairwell the device worked well enough to possibly be functional for its intended purpose, which was to be in a classroom situation. The only location where it worked perfectly just like at home was within an elevator cab with the door closed. Oddly, there was one particular location in a hallway where it functioned to some degree better than the nonsense it showed in most locations. Everywhere else it would read either very low distances, i.e. the echo signal is coming back too soon, or there would be random zinger interspersed with a very rare correct distance reading.

    Keep in mind the unit worked perfectly at home and in the elevator cab. The project design included capacitor filters mounted close to the device. The capacitors made a performance improvement at home.

    Needless to say I am terribly disappointed. I am guessing the electrical noise is from all the HVAC motor circuits on frequency drive controllers.

No public wish lists :(