RaceCapturePro2 digital output issues

[BrianC]

I'm having trouble using the digital outputs of my RaceCapturePro2.

I set the three digital outputs to output mode.

I wrote a script to toggle one of the digital outputs between on and off once per second.

When I put my multimeter probes on the 5v reference and the digital output, the voltage changes from 0 to 5 and back every two seconds, as expected.

However, when I put my multimeter probes on the ground and the digital output, the voltage always reads 0.

When I set two different digital outputs to different values, the voltage between them always reads 0.

Is this expected or am I doing something wrong?

When I did the same test on an Arduino, everything works as I would expect. I'm able to read the voltage between the outputs and the ground. I'm also able to control an external device with the Arduino that I would like to control with RaceCapturePro2. The device connects to ground, 5v reference, and three digital outputs.

[brentp]

Hi,

The output are working as expected. See the specs here:
https://wiki.autosportlabs.com/RaceCapt ... ifications

The outputs are open drain that switch to ground when activated, and are an open circuit when not activated.

A classic way to use the outputs is to activate an accessory, light, relay in the following way:

12v ---- (+) (device) (-) --- RaceCapture/Pro GPIO output

Hope this helps!

[BrianC]

Thanks Brent,

I understand how this could be used to connect an output to one or more LEDs.

In my case, I'm trying to use the outputs as inputs to a microcontroller that controls a larger number of independent LEDs. I'm connecting the three digital outputs, the 5v reference, and the ground to the device.

Based on your reply, I think I would need something like this:

Code: Select all

            input 1      input 2  input 3    power         ground
               |           |        |          |              |
               |           |        |         RCP 5v ref     RCP group
5v ---- (+) (relay) (-) ---|--------|---------- RaceCapture/Pro GPIO output 0
5v --------------- (+) (relay) (-) -|---------- RaceCapture/Pro GPIO output 1
5v ------------------------ (+) (relay) (-) --- RaceCapture/Pro GPIO output 2

Does this look right?
Any advice about what kind of relay I would need?

[brentp]

You can simulate the 0-5v signal you need by tying our GPIO output to a pullup resistor to 5v, on your arduino side.

[BrianC]

Thanks, Brent.

This worked fairly well.

In hindsight, using the digital outputs probably wasn't the best choice for high speed communication between the RaceCapturePro2 and the Arduino. I would probably have better luck using the aux serial connection to transfer information at a faster rate.

I noticed I had to wait a couple of ticks after setting one of the digital outputs before I could set it again to a different value.

[brentp]

Glad you got it working. Yes, CAN or RS232 serial might be better options!