mewanderinghome wrote: ↑
Jan 30 2020 12:59pm
Yeah it seemed to me that this latest CA can act as a primary display (with temperature power roll-off & a lot of other customizability), if I went to the work of re-routing cabling. If I understand correctly, it seems the CA would be installed inline with the throttle cable, and the brake cutoff cables (one of which I'll probably nix anyway) would then terminate at the CA, not having to go into the downtube. But I'd have to extend the torque and cadence cables (are these one integrated cable?) up to the CA (along with a temp sensor cable).
you'd also need to figure out how to wire that torque sensor and cadence sensor to the pas connector of the ca v3, including what voltage they require (the torque sensor is probably more than 5v, the cadence is probably 5v), so you can ensure it gets what it needs. the pas ca v3 connector provides 5v and 10v, anything else you'd have to come up with separately.
configuring the sensors in the ca is done per the pas menus, once it's attached and working, and is easy enough but may take iterative experimentation to get it responding the way you want.
I also ordered a gear change sensor that I may or may not use, but I don't know the location of that on the bike (guessing it's some sort of tension sensor inline with shift cable somewhere?), so not sure if that's a cable I'd have to shorten or lengthen.
the gearsensor is basically like the hwbs hidden-wire-brake-sensor, where whenever the gearsensor detects cable movment it gives a pulse to temporarily turn off the motor. (the hwbs stays off once cable moves past a certain point, because it isn't springloaded inside like the gs likely is).
if it's output grounds momentarily then you can just wire it in parallle with the ca's ebrake input. then whenever you shift the ca will momentarily stop providing throttle to the motor...but you would have to have maximum ramping 99.99v/s for throttle off in the ca to ensure it turns throttle off fast enough for it to make any difference to shifting.
I thought I saw a CA video that showed how to adjust the torque level at which the CA starts sending go-juice, but you're saying 50 rpm is the minimum?
i was pretty sure that's the limit, but i can't find a specific post or page in the manual stating this in this way. there are statements that 50rpm is the minimum pas assist start, which is probably why the torque won't start below that either.
if you have a high-pole-count cadence sensor (i think 24 is the max for the ca?) then it doesn't take much of a rotation to give a 50rpm count into the ca...but it does take some amount of crank rotation before it will start from either torque or cadence sensor.
on a regular bike of regular weight with regular rider you will probably not have any problems because of it...but you'd have to experiment to see if this is sufficient for you.
according to justin_le here they've been trying to change so the torque sensor works by itself, but hadn't done it yet, that was a couple years ago, and the latest firmare (3.13?) i tried it in was no different for me:
i haven't even tried to do it in a while; i'm presently not even using the torque at all (tdcm bb) just cadence off that bb sensor, which works reasonably well if not perfectly, once i'm moving (a cadence sensor with more poles would work better, and possibly one that is not on the cranks but instead is on the gearing stages after that might work better, i have an experiment planned to test this, eventually). but i have to startup with the throttle, most of the time. (if i'm on level ground or a very slight downslope i can start pedaling and it will start moving and provide a very minimum assist, enough to keep moving at that speed, barely, but it won't accelerate and allow me to be able to pedal fast enough to get it going any faster, and i have to use a throttle blip to get going. if i'm on a little better downslope, still extremely slight, it'll get going normally. if i'm upslope at all, i can't start it up without the throttle.)
afaik the original idea behind the minimum was that this would help prevent a bike from just taking off under you when you stand on the pedals at a stop to ready for startup, or when mounting a bike, etc. but having it as a hard-coded limit makes it problematic for a number of usage scenarios, which while rare are not unheard of.
on regular bikes with regular riders under regular conditions none of this matters much, but it does matter for some, and for unusual cases like mine.
the only workaround i know of (other than just using the throttle to get going) at present is to have a "startup" button or switch somewhere that either provides a fake cadence signal to the ca so torque works as if you were already going, or provides a throttle signal of sufficient voltage to get you going, wehther or not you actually ahve a throttle on the system (temporarily bypassing the ca's actual throttle output, or providing a signal to the ca's throttle in connector, whichever is required based on your other ca settings).
If so I totally agree with you--I want assist from start as long as I'm really bearing down on the pedal and not just resting my foot there.
in the ca, you can "zero" the torque sensor at whatever level you want, so you can either zero it without feet on there, or zero it with them, but this would only be really useful if it would initially respond to torque without rotation.