A rover that stops before it hits anything
Ten parts on one printed plate, designed, wired, programmed and checked by Haviland. The gate turned it down four times before it passed.
Challenges
The gate turned it down four times before it passed.
Run 1: a wheel sat inside its motor.
Run 2: a cracked vendor mesh couldn’t be measured where a part sat flush against it.
Run 3: six AA cells, less the driver’s 2.55 V drop, put 6.5 V across a 5 V motor.
Run 6: one check still can’t run, because a second physics model isn’t installed here.
Solutions
The gear motor isn’t symmetric about its axle, so the left one now turns the other way and both show their clean side to the wheel.
The motors hang on zip ties, clear of the plate, so every gap around them can be measured.
The firmware caps the motors at 196/255, so 6.5 V averages 5.0 V. The simulator confirmed the cap is in the code; only the real motor can confirm it works.
The gate still says FAIL with zero errors. It never rounds “unmeasured” up to “fine”.
Results
All four requirements pass in simulation: it stops in 68 mm, inside the 200 mm it keeps clear; it stops within what its sensor can see; it runs about 2.4 hours on six AA cells; and it stands on its own wheels.
Nothing here has met a real floor yet.
68 mm
Simulated stop
2.4 h
On six AA cells
4 / 4
Requirements met