Chain tensioning has always been a problem for 548. We’ve tried slots for idler sprockets, discrete holes or slots for acetal sliders, offset-drilled acetal sliders, idlers on offset-drilled shafts, double-drilled acetal sliders, and more. All of these have one of two problems. Either they don’t have enough positions or lose tension over time. I came up with this design to avoid both of those problems. SlidyTension is infinitely adjustable, compact, cheap,  easy to adjust, doesn’t move under load, and customizable for different sizes of bearings or travel lengths.

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Battery Test

Now that the Jaguar motor controller has reached its end of life, they are accumulating in FRC team shops. Team 548 had around two dozen hiding in a tote. One use I found for them is testing batteries. After many brownouts during the 2016 season, we wondered if the batteries were faulty. My first plan was to use a robot, but it was hard to eliminate variables, noisy, and overheated motors. After returning to the drawing board and doing some digging, I found a roll of steel high-temperature wire which had a total resistance of around 0.58Ω, able to burn about 14 amps at 8 volts for hours on end. With a spare Jaguar, box fan, and that wire, I constructed and programmed a 10A constant current load with PC data-logging. Continue reading Battery Test

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