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Strider by David Buckley April 2009
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  • Strider Software

    Strider was made over a weekend to be used in filming in Millenium Square, Bristol, pilot footage for a TV show "Robot Relays".
    I thought a three foot high biped robot would have more visual impact than the TecFoots at 2 foot high and the Amblers at 9 inches.

    Originally Strider was fitted with a Hitec 805 (24.7Kg.cm) for the Stride servo and a Hitec 755 (10.5Kg.cm) for the Roll servo both powered from a 7.2v Racing Pack. However they were not really powerful enough and although Strider walked it didn't walk very well and couldn't skid turn. Running the servos from 12v helped but performance wasn't satisfactory.
    I moved the 805 to the roll position which was much better and tried for the stride servo a 24v motor/gearbox I had used for the Cycler Arms and in various animatronic figures but it needed gearing. Later I tried a Hitec 785 Sail Winch which using a pulley system had nearly enough torque but the positioning accuracy was appallingly bad, maybe alright for winching sails but was no good as a Stride servo.

    During cleaning after a Maker Faire Strider had fallen off the bench and broke a leg so I glued it back together and added stiffners to the legs. Then earlier this year, 2011, I learned about the Tower Pro 9805 and bought some, which is another story (two were very fake). I fitted one per leg as stride servos and modified the hip bearing to have less friction. That done Strider worked well from 7.2v racing pack or from a 5v supply.

    Later after building Jet Laser I removed the original BS2 controller and fitted an Arduino with a PicAxe14m2 to receive IR commands.

    I was never very happy with the power of the HiTEC805 roll servo so in July 2019 I bought a 60Kg.cm 1/4 scale servos from AliExpress and fitted it as the roll servo. However stopping pulsing does not turn off the servo, it continues to hold at the last pulse position and needs to be depowered to relax Strider. On power-on it is fine and does not hold until the first pulse is received.

    In 2021 during Covid lockdown I fitted rubber feet on the heels and support block at the toes to give Strider an arched foot so it wouldn't wobble on uneven floors and to prevent it rotating on the stance foot as it made a stride. At first I used rubber feet on the toes as well but they gripped too much for Strider to skid turn.