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  1. Parallax Heads to the Capitol

    Last week the Parallax team packed up and headed to the nationís capital to participate in the USA Science and Engineering Festival held at the Walter E. Washington Convention Center in Washington, D.C. The event on April 28th and 29th 2012, drew over 100,000 attendees including thousands of science-minded children, educators and industry.

    Click image for larger version

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    The Parallax booth quickly became a popular destination. Robot playpens allowed visitors to observe
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    Categories
    Robotics , ‎ DIY and Hacks
  2. Finals are over and I am done for the term !

    by , 05-04-2012 at 07:50 AM (Fixing the world . One electron at a time .)
    I handed in my paper and did my last radio show on KULT-FM 94.5

    Now to head neck deep in to the UNI solar boat .. BTW runs 2 parallax Micons

    a SX48 ( that I have fell in love with for the MPPT that BTW has hit a peak of 97% eff ! ) and a BS2 for a telemetry computer .

    last week I made a HUGE buss bar assembly. If all goes as planned we will have over 1000A flowing and upwards of 36kW of power for 30 Sec on a 400 Lb boat ..

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    Categories
    Uncategorized
  3. Programming leg movements - tibia

    Quote Originally Posted by DiverBob View Post
    I was able to use the same routine I developed for the Femur movement on the Tibia movement. The only difference is the Tibia uses it's own set of ADC values to calculate angles. I am able to use the PST to input angle values to both actuators and the leg responds correctly.

    I started working with the Coxa control but ran into some issues where the position encoder doesn't appear to be sending the HB25 any signals. I've successfully used this combination before so I'm not sure what
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    Categories
    Propeller , ‎ Programming , ‎ Robotics
  4. Programming leg movements

    Quote Originally Posted by DiverBob View Post
    My entry from a few days ago disappeared, must not have gone out correctly. Anyway, I'm off of night shift and am getting used to sleeping during the night again.

    I got a new software routine developed where I send the femur (lift) motor the desired angle and the femur moves to that position. I mapped out all the angle ADC values from 35 (minimum angle) to 155 degrees (maximun angle) in 5 degree increments. I plotted the results and they aren't exactly linear. I was unable to develop
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    Categories
    Propeller , ‎ Programming , ‎ Robotics
  5. Is there a recommended external DAC that works well with the prop?

    I may need to understand this later.....

    Quote Originally Posted by jmg View Post
    One detail to watch if looking for precision, is the way the DUTY mode works, is it is really Pulse Density Modulation.

    The gotcha hiding in PDM, is the tplh and tphl times matter, and any skew will give a change in voltage, especially at large changes in pulse density.

    I believe the scope shot in Fig 11 of AN001, is showing such an effect : notice the step at 50%

    This is somewhat aggravated by
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    Categories
    Propeller