Mini-Flip Planning Notes

Mini-flip is the third in a series of Fred Photopopper Turbots. The previous two, Flipper and Flip Boy, have two main difficulties. The worm gear motors seize and the robots are not light-seeking.

Reducing torque on the motor itself, improving mounting motor to body, and improving mounting flagellum to motor are all ways to keep the motors from seizing.

Mini-Flip will be much smaller than its predecessors. This is because torque varies with length. The shorter the flagella, the less the load on the motors, and the less likely they are to seize. Kyle Simmons’ tiny Termite appears to bear this conclusion out for its motors have never seized.

Flipper and Flip Boy use two wire-ties to mount the motor. First is a wire-tie across the motor casing. Second is a wire-tie between the motor case and the motor shaft. We suspect that this second one is rubbing against the gear and contributing to the problem. For Mini-flip, we will be replacing this tie by press-fitting the motor into a hole in the Sintra.

To mount a flagellum to these motors, Dave Hrynkiw recommends "using a suitable diameter of brass tubing that would friction-fit over the output cam, then drill/pin it into place, AND use some epoxy." This is the same technique used by Mark Tilden in robots such as THAB and Turbot 1.0. We purchased some 9/32" brass tubing, which appears suitable.

The reason these Flip turbots do not seek light is because the Fred Photopopper circuit has no means of telling up from down and acting accordingly. We are going to stick with this circuit, however, and attempt to address the problem mechanically.

Bjorn Brindefalk described a turbot motion comprised of two movements. Movement A flips the robot toward the light. Movement B turns the robot in place, positioning for the next flip. We are going to implement this motion by having one flagellum so short that it turns rather than flips the robot.

Mini-Flip Planning Notes

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