Convert PAS sensor to torque sensing bottom bracket without CA v3

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MasonSteele
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Convert PAS sensor to torque sensing bottom bracket without CA v3

Post by MasonSteele » Jan 11, 2018 12:50 pm

Hey guys,

I've mostly used throttle only ebikes and recently started experimenting with PAS systems. I would like to try a TDCM torque sensing bottom bracket now, however I'm noticing some differences in how they are connected to the controller. All my current PAS sensors only have three wires running to my controller, and I'm seeing that the bottom brackets use a 4 pin connector (some even seem to have 5 pins). Is there any way for me to swap out my PAS for a torque sensing BB without using an intermediary cycle analyst?

much appreciation,
Mason

MasonSteele
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Joined: May 31, 2014 11:18 am

Re: Convert PAS sensor to torque sensing bottom bracket without CA v3

Post by MasonSteele » Jan 11, 2018 12:58 pm

Sorry, where I typed PAS previously, I meant Cadence sensor.

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amberwolf
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Re: Convert PAS sensor to torque sensing bottom bracket without CA v3

Post by amberwolf » Jan 11, 2018 1:25 pm

If your controller does not have the specific stuff built into it to handle the various torque-sensing BB outputs (there are a few different ways they work), then it can't interpret the data from the BB and won't work with it.

If it only has a cadence sensor now, then it's unlikely to be able to understand any data but whatever that sensor puts out, which is probably just a string of pulses at crank speed.

You'd have to check with the manufacturer of the controller itself to be sure, but it's unlikely it can do anything else than what it does now, without an intermediary electronics of some kind.

Additionally, if it does not have a throttle input, the CA has no way of sending it the torque-sensed control information to control it's power. If it does have a throttle input, as well as a cadence input, then the CA can work with it.

MasonSteele
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Re: Convert PAS sensor to torque sensing bottom bracket without CA v3

Post by MasonSteele » Jan 11, 2018 2:10 pm

Thanks for the detailed response. Really appreciate it. I see I'll need the CA - it might look a bit weird to have both the Xiong-da computer and the CA in my cockpit, but I'll give it a go.

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amberwolf
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Re: Convert PAS sensor to torque sensing bottom bracket without CA v3

Post by amberwolf » Jan 12, 2018 1:32 am

You don't have to have the CA on the bars, unless you need to read data off it's screen. You can just set it up for how you want it to work, then keep it elsewhere on the bike.

If you need to change modes on it there are ways that can be done remotely listed in the CAv3 beta thread or Teklektik's UUG (both linked from the http://ebikes.ca CAv3 info page).

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