Using Digital Expansion Port for Analog Signals

All sensor specific discussions! Temperature, pressure, steering angle, brake and throttle, etc. Post adaptations of OEM-style sensors, and also your clever DIY hacks and custom designs here too!

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harveyf
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Joined: Fri Aug 30, 2013 12:23 am
Location: New Hill, NC
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Using Digital Expansion Port for Analog Signals

Post 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.

Harvey
Harvey Ferris

neoraptor
Posts: 43
Joined: Thu May 16, 2013 3:08 pm
Location: Alsace, France

Post by neoraptor »

Hello,
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:

brentp
Site Admin
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Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi Harvey,

We're currently testing the CAN bus expansion port for RaceCapture/Pro https://github.com/autosportlabs/CANx

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!
Brent Picasso
CEO and Founder, Autosport Labs
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harveyf
Posts: 8
Joined: Fri Aug 30, 2013 12:23 am
Location: New Hill, NC
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Post 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.
Harvey Ferris

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