viewtopic.php?p=571345#p571345
and the wiki
http://www.endless-sphere.com/w/index.p ... t_v3_Setup
and the official CAv3 store page
http://www.ebikes.ca/store/store_CAV3.php
for those searching for info in this long thread)
Hey everyone, so I alluded back in the RC-CA thread last year that we'd basically hit the ceiling of what could be fit in that board layout and were working on a new model with more I/O functionality and software space. http://endless-sphere.com/forums/viewtopic.php?f=28&t=29846&start=145
There've been a few kinks to work out and board revisions since then, but we had a good demo built in time for the Taipei bike show earlier this month. Here was our ghetto booth setup were you could turn the crank, look at your human power generation on the CA and watch either the hub motor or the RC motor spin up in response:
- Taipei Setup.jpg (54.53 KiB) Viewed 13802 times
The back end of the circuitboard now looks like this, with the top row having all the new input/output headers:
- CA V3 Board Details.jpg (97.87 KiB) Viewed 13802 times
Communcation: There is an Rx / Tx and Gnd for hooking up a TTL->USB converter. This can be used for datalogging, plus bootloading new firmware, and configuring setup parameters from a computer rather than by pushing buttons through the setup menu.
Temperature:This input can be either a 10K NTC thermistor, or a linear temperature sensing IC like the LMx35 series. It has an onboard 1K pullup to 5V, so with a 10K thermistor you get good sensitivity in the 80-100 oC temperature range where it matters, and with the IC devices like the LM335 that act like a zener diode you don't need a separate 5V either, just the same 2pins.
Aux Pot Input: This is a general purpose 0-5V input that can be used either with a potentiometer or any number of 2/3/4 position switches with resistor dividers to scale any one of the limit parameters on the fly while biking.
Ebrake Cutoff: Brake inhibit input, has onboard pullup as well so you can use either a mechanical brake switch or a hall effect device. This way you don't need brake signal wires going all the way back to the controller, they can go into the CA and then the CA cuts the throttle signal.
RPM / Dir / Trq: The pedal assist connector was laid out primarily with the THUN torque sensing bottom brackets in mind, but will work fine with regular PAS cadence sensors, as well as the torque sensors we saw from two other companies at the Taipei show (FAG from germany and GreenTrans from taiwan). The 10V bus can power the THUN sensor directly provided you are using a pack that is 48V or less. For higher voltages the CA's regulator would get hot and you'd want to feed the THUN 12V power from a DC-DC. RPM is where the cadence pulses are measured, and the Dir input lets it distinguish between forwards and reverse pedal motion. So this works both with quadrature encoded signals like the THUN, or with regular PAS sensors that have pulses on one signal and a steady fwd/rev on another.
External VPack: Finally, the last input is for a separate battery voltage signal. For people running >100V, this gives the option of wiring up a resistive divider at your battery side for sensing the pack voltage and feeding just this signal to the CA, with the CA itself being powered from a lower 12V bus or similar. This is a much safer approach for higher voltage systems than powering the CA directly at those levels, and it means up to 650V packs could be supported.
One of the main objectives for all of this was so that we can consolidate all of the different ebike/human interface signals into the CA, have the CA act as a customizable brain for how these things should interact, and then provide a single command to the throttle input of any model of motor controller. That way litterally any existing ebike system could be upgraded for torque sensing PAS assist, over-temperature rollback etc. Like this:
- CA V3 Functional Sketch.jpg (25.21 KiB) Viewed 13802 times
