Sending data back to the OI

Hi all,

I was wondering if it would be possible to send data back to the operator interface in order to fire a sound alert. Can I send back any data through any of the pins on the joystick ports or the dashboard port (to a custom circuit that would fire the alert)?


No, not really.

The problem isn’t sending a signal to a joystick port, there are some LED level lines available to you to light some LEDs if you like, the problem is there isn’t enough power available that way to power an alarm. Outside power sources aren’t allowed to be used in conjunction with the joystick ports.

However, you can send data to the dashboard port and have something like a laptop hooked there sound an alarm.

The other problem is, it’s very unlikely that you’ll be able to hear an alarm during competition anyways, unless you use headphones. It’s so loud in the driver’s staion that even while screaming to the person next to you, they don’t always hear you.

Just to get it working, even if not for use at a competition, how would I send the signal? (Assuming that I can power the alert)


From what I remember (and if you wait a few minutes I’ll dig up the whitepapers) the Dashboard program can receive the status of the PWM lights. In your code, there are lines that look like this:
Pwm1_green = 1;
Pwm2_red = 0;

And so on. They aren’t in that order, but you get the point. These are what cause the red/green lights on the OI to change. You can write a program for the computer (hopefully you can do this) to get the Dashboard packets (again, I’ll dig up the applicable whitepaper in a moment). That program can play a sound if the lights are in a certain state. I’m sorry I don’t have specifics at the moment, but I will edit this as soon as I do.

I also might write a program to do this soon, just to see what I can do.


EDIT: I found the list of whitepapers.
I might write something to do this, I might not. Hopefully you have someone on your team that can write programs for the computer. Good luck!

See pages 5, 7, and 9 of the OI Reference Guide.
[font=Verdana]It’s from 2005 but applies to 2006 as is.[/font]
[font=Verdana]It gives you both the proper pinout and the variable names accessable from with the RC user program to set the lines high or low.[/font]

Just be sure not to attempt to draw any power from the joystick port or it could permanently damage your OI.

Don’t bother with sound, but I would highly reccomend a laptop for the dashboard port. Try to integrate it nicely in your controls.

We connected an opto-isolator chip to the OI port 3. We connected pin 15 to the LED anode on the opto…and pin 12 to LED cathode. The OI provides current limiting. We connected the transistor to +12V (provided from outside the OI…another battery). Connected the opto transistor emitter to a 4.7K resistor to 0V. We tapped the emitter to drive a MOSFET. Used external 12V on one end of MOSFET…and a 12V lamp on the other. Voila!!

It worked well.

Regarding rules, are we allowed to bring a battery to the operator station to provide power for external circuits??


Check with Q&A to be sure, but since you’re allowed to bring batteries for Dashboard-like devices, I’d imagine that they’re fair game for that.

Yes, but

Do you suppose connecting an opto-isolator is okay with this rule? The OI power supply is driving and LED and no other circuits. The isolation ensures no electrical connection. The external battery would then support 100% of external circuitry.

Billfred, I’ll check the Q&A.


I “suppose” that the words

External power sources of any type are not permitted on any equipment connected to the Joystick Ports.
mean that if your device connects to the Joystick Ports, it cannot get power from anything other than the Joystick Ports. The words “isolation” and “electrical connection” are not present in the rule.

However, what I “suppose” is not relevant. If you want an official answer, submit an official question. Which I see you’re planning to do, which is good. Now we can all find out the correct answer.

The Q&A site says “No exceptions!” in response to using opto-isolators on the OI ports.


That’s what I expected, and what I feared. If you want to get feedback from the OI into a powered device, you’ll have to find some way to do it other than the LED driver outputs.