New robot pictures

Here are some new robot pictures. I have a much better mount for the sensors now and they are working as well as they can. Unfortunately, I don’t think passive infrared motion sensors will work for what I want. They’re too erratic for use on a robot. They’d be fine for a stationary unit that needs to detect motion by “hot” objects such as a cat or a human and take some action. But for a moving object, they take too long to calibrate. They generate unreliable information.

I’ve ordered an ultrasonic rangefinder, which will look sort of Wall-E-ish. It should fit into the same “face”, but if not, it’ll be easy to make a new one.


  1. Finicky Infrared Detecting Object – FIDO – perfect name for a cat chasing device

  2. Yes, I’ve lived with several, but not since leaving my family home.

  3. Maybe you need both types of sensors the IR sensors could be used along with the utrasound ones to detect cats that are quietl and waiting to ambush the robot!

    • Possibly. The ultrasound is actually a rangefinder, so I can get distances with it.

      The problem with the passive IR sensors is that they already have a bunch of circuitry that looks for heat movement. So rather than getting amplitudes, I’m getting a high/low signal, where it signals high while it detects movement. The signal goes to low when the movement stops. It’s just two values.

      Also, it takes ten seconds or so to calibrate and I suspect that it’s losing calibration when the robot moves.

      So I’ve ordered the Ping))) ultrasound detector and a couple of clicky switches that I can use for collision detection. It’s amusing seeing the robot spinning its wheels against a table leg, but it’s not good behavior.

  4. I got the PING))) sensor in the mail. It’s *tiny*! It’s about half the size of the two passive infrared sensors. I’ve cut a new piece of foam core and mounted it. I think I’ll get some basswood or something for a more permanent mount if this works…

    Anyway, I’ve tested it and it detects distances up to 3 meters. It returns a large value of microseconds (21460ms) which evaluates to 370cm for objects farther away.

    I also got the proximity switches, so that it can detect if it has run into a wall or a table leg or something.

    More coding…

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