Any one using this with a Joroto X4S?

[MitjaHenner]

I have a X4S and am thinking about building a SS2K (probably a non PCB version because I should have all the parts from tinkering with 3d printers, lasers and cncs).

I think Bluetooth only shows cadence, but the display shows resistance (maybe it's possible so get something from the sensors directly).

[doudar]

We've made a ?couple? for the Joroto S2. Adaptors can be found here https://github.com/doudar/SmartSpin2k/tree/develop/Hardware/Common%20Assets/Arm
I would expect that if it has bluetooth, it would send power, cadence and possibly resistance. If it sends resistance and cadence only, it could be computed on the SS2k, we would just need to add another decoder, which could be fun.

[doudar]

Let me know what you find out!

Decoders are in https://github.com/doudar/SmartSpin2k/tree/develop/lib/SS2K/src/sensors

Then if it's a custom characteristic, the uuid will need to be added to the scanning and connection routines in BLE_client.cpp

[doudar]

I created a discussion here as well: https://www.facebook.com/groups/149984563348738/

[cagnulein]

I'm here too :)

[doudar]

@MitjaHenner , if you have access to power meter pedals, we (Roberto and/or I) would love to get access to the data to create a power lookup table.

[MitjaHenner]

Probably have some more time over Christmas and might be able to borrow a pair.

[MitjaHenner]

Looks like it's only reporting the battery level and cadence over bluetooth.

The resistance sensor is just a sliding pot, so it should be pretty easy to grab the % value.

[jrbarrick]

I've got the X4S as well, and just received a batch of PCBs. Can confirm it only reports speed/cadence over BLE, wish I'd actually researched any of this before I got it a couple months ago. I was able to wire up the pot to the unused GPIO35 and write a bit of code to read the value and calculate the resistance to match what the panel is showing. The onboard computer sends 3.3V to the pot, so I can run the SS2k inline with the computer connected and only need to connect to ground and the wiper. I stuck a pullup resistor on GPIO35 as well so I can use the 4095 value as a bit of crude detector to see if the pot is connected or not, as even at full resistance it doesn't quite hit that.

However, it's been about 20 years since I last touched any C++, so all I've done is just drop the few lines of code in the 2 sec maintenance loop so I can print the values over serial as a test. I've got no idea from here about to actually make this data useful anywhere.

[doudar]

I'd love to see a pull request on what you've done.

Basically, as far as reporting power, you need to come up with a lookup table or simple math (what the IC4 uses, essentially cadence * resistance value), and then do:

 rtConfig->watts.setSimulate(true);  
//fancy math or your table implementation here
rtConfig->watts.setValue(value.toInt());