Non-zero Speed At Stop Sign

[gregh3285]

On two occasions in the last week or so, I've come to a stop sign and my iBike's speed measurement didn't drop to zero. I was well over ten seconds at a constant speed (2.3 mph if I remember correctly). When it happened yesterday, I spun the wheel for a moment to get a speed other than zero. When the iBike's speed again settled down, it went, properly, to zero. I have recently upgraded my firmware to v1.18. The most current occurrence was running on v1.18. I'm not sure if the first time I saw it I was on v1.16 or v.1.18. I've never seen this behavior before recently. Has anyone else seen this? In both cases, I was riding alone. In one case I was in town. In the other I was quite a ways out in the countryside. My main iBike battery was at 2.91 Volts. I am running a wireless configuration.

[racerfern]

If you come to a stop and the speed magnet is close to the sensor, you might trigger it with the slightest of rocking. If it happens again try moving forward a few inches and stopping. The magnet should be far enough away at that point.

[gregh3285]

Fernando, good thought. I did check that the magnet was away from the sensor (and didn't mention it in my original post). To me, it looks like the speed calculation inside the iBike is using digital filter to calculate a time averaged speed for display. And, it's almost as if the logic that allows the iBike to go from the bike-is-moving state to the bike-is-stopped state isn't triggering quite correctly in certain conditions. In cases where this state change doesn't trigger, the last non-zero speed is displayed until the unit receives another impulse from the wheel sensor. I can send somebody the .csv from the first time I had this happen if it would be useful.

[gregh3285]

On tonight's ride I got the behavior to happen twice. In both cases it occurred when I came to hard stops at a stop signs. In both cases I was able to clear the issue by moving the magnet across the speed sensor once or twice.

[coachboyd]

Try switching to a different magnet and see if that solves this. I had a problem with a magent that would cause the speed to get stuck if I started coasting (it made coastdowns inconsistent and a pain. For every 10 coastdowns I would get 2 that would be good). After a magnet change I have not seen this problem since (and my aero values for the coastdowns were all within .007 of each other).