Yeah, I actually thought I'd been in Mission, but the phone app said Cruz. I wonder if the loss of power also toggled the shaping somehow.

Riding along, just getting onto the ramp into a parking lot, my OW+ stopped going. I of course kept going, though it was a minor fall and nothing but a bit of road rash.

When I returned to the OW+ after brushing myself off I was surprised to find that it was powered off. Powered off as in, phone app not connected, no lights, no blue LED. I had to power it back on to keep going. This seems odd -- certainly different from my previous falls. It even seems suspiciously like a board issue rather than user error (although I still assume it was some sort of user error -- I'm under 100 miles and still working out the kinks).

To cover the obvious bases: Battery at 82%, Cruz profile, traveling at low speed (perhaps 6 mph), going from flat road to slight upward incline.

I'll admit it makes me a bit nervous -- if there's a sudden power-off condition and it happened at speed or near traffic I could be in quite a pickle! Is there a known behaviour that I might have tripped through inexpert riding or should I worry that there's a loose power coupling?

I mostly cruise about 13mph; this is because I am old and fragile and don't want to die just yet. In praise of this speed, however, let me point to my constant companion in my automotive research job, the fatality/speed graph:

Note the sharp increase from 20 kph (~12 mph) to 30 kph (~18 mph).

Now this doesn't mean we're risking death -- those numbers are for car collisions, which are more like going full speed into a wall than like falling off a plank, and those folks weren't wearing helmets. But it gives you a good idea of how much the hazard level starts to ramp up as you push toward 20mph. Roughly, energy goes as the square of speed, injury goes as the square of crash energy, and in a crash all that energy has to go somewhere.

(also: helmet!)

Most gyros-on-a-chip are MEMS coriolis gyros (vibrating rings whose vibration modes rotate while the ring itself does not) or fiber optic gyros (where a light pulse in a a fiber optic loop is the "moving part"). Low-end MEMS gyros run about $2 in large quantity and can be only a few millimeters, so that's the way I'd bet.

So actually a gyro, but a really tiny one with very little inertia. And really tiny gyros can "spin" physical abstractions like vibrational modes and photons rather than hunks of metal. It's the same physics and math as a classic gimbal-and-ring gyroscope, but tiny and cheap and won't take your finger off if it slips.

@djinn Can't control two orthogonal parameters with only one actuator, though. With only the motor in the wheel, I don't think every possible mix of tilt and torque is possible.

@gadgetrider The last brake chopper I worked with (on an agricultural robot) weighed five hundred pounds and needed a separate radiator to keep from melting, so my knowledge of such things has little application to the OW.

In general the OW design seems to be working near the limits of practical heat dissipation, so I am confident that FM's engineers have considered this.

@djinn With most motor systems, that is precisely regenerative braking -- the amount of battery power to apply negative torque is negative, so you get regeneration for free with braking. The only limit is your ability to sink that power, which is why heavy vehicles with regen brakes also have a "brake chopper" (a huge resistor bank) to sink more power than the battery can take (and then a huge heat sink to dump the resulting heat).

Okay, here is one data point: T cops watched apathetically as I locked up my OW+ in a bike cage. So that's apparently legit-ish, even if technically prohibited.

(To live in Boston is to live in the gray zone between what is illegal (nearly everything) and what anyone actually cares about (nearly nothing))

My first couple of crashes were on the sidewalk in front of my house with my ten-year-old daughter sitting on the stoop and laughing at me every time I went into the concrete. Smiles all around.