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Using Digital Expansion Port for Analog Signals

Posted: Thu Nov 21, 2013 1:26 am
by harveyf
Brent (or Anyone)-
By the time I allocate 7 analog channels, there's nothing left for 4 channels to measure suspension/shock displacements. I plan to use 7 channels for wheel speed, steering angle, throttle position, brake pressure, oil temp, oil pressure, and water temp.
You hint that the Digital Expansion Port can be used to add "more analog or digital channels". Care to enlighten me how this might work?

Having read the sensor threads, it looks like either the BMW headlight position sensor or the optical proximity sensor are 2 options for measuring suspension movement.


Posted: Thu Nov 21, 2013 8:41 am
by neoraptor
On the RCP unit, you have :
* 6/7 analog inputs: steering angle, throttle position, brake pressure, oil temp, oil pressure, and water temp
* 1/3 frequency inputs: wheel speed
* 3 digital inputs
* 2 extension ports (RS232)

You will need to build some interface to get the data from your sensors and then output it in serial format to this port using a micro-controller for example.
The only problem, is that there is no documentation about the communication protocol or the communication settings (baudrate, parity, ...)

Wait for Brent for more details :wink:

Posted: Sat Nov 23, 2013 2:50 am
by brentp
Hi Harvey,

We're currently testing the CAN bus expansion port for RaceCapture/Pro

This will give the system CAN bus connectivity, which will allow you to connect to external systems - OBD2, sensor expanders, and other devices.

Typically the strategy will be to place the low frequency sensors on the external bus, and dedicate the higher speed sensors for the internal channels.

Hope this helps. Watch for news as we complete our testing!

Posted: Mon Nov 25, 2013 2:34 pm
by harveyf
OK understand.

Shock displacement data will certainly be higher frequency. Conversely, the engine parameters (pressure and temp) should be pretty static and should be good candidates for the CAN bus.