IFI Control System to Wifi?

[talltree357]

I am currently working on a project and could use some help. I have currently built a robot utilizing the 2004 FRC control system, however instead of using RF, I would instead like to communicate over wifi. Is this possible? My plan so far is to eliminate the transmitter/receiver, and in its place use 2 wireless routers connected to the same IP address. To connect the routers to the OI and RC I was thinking I could use this RS-232 to Ethernet cable.

http://www.superdroidrobots.com/shop...asp?itemid=753

Would this work? If not, does anyone have any possible solutions to my problem? Thanks!

[EricVanWyk]

Originally Posted by talltree357

I am currently working on a project and could use some help. I have currently built a robot utilizing the 2004 FRC control system, however instead of using RF, I would instead like to communicate over wifi. Is this possible? My plan so far is to eliminate the transmitter/receiver, and in its place use 2 wireless routers connected to the same IP address. To connect the routers to the OI and RC I was thinking I could use this RS-232 to Ethernet cable.

http://www.superdroidrobots.com/shop...asp?itemid=753

Would this work? If not, does anyone have any possible solutions to my problem? Thanks!

That looks expensive for what it does. It'll probably work though.

My group at TI makes a serial to ethernet module eval kit for less than half of that cost: http://www.luminarymicro.com/products/mdl-s2e.html

You can probably find others for similar or better costs if you look hard enough, I just had that part number on my mind from work earlier today.

PS: My boss would kill me if I didn't mention it, please don't hurt me. We make a bunch of eval/dev kits that have ethernet connectivity. If you are up for a slightly bigger challenge, pick one of them up.

[nathanww]

For the router and bridge to understand the signal from youroperator interface, you'd have to convert it into TCP/IP networking data. A 2009 or 2010 control interface will do this automagically, but an older one based on the IFI OI unit will require a custom-programmed "gateway" to sit between the OI and the router.

The same thing applies in reverse on the robot end. The IFI controller can't understand your TCP/IP encoded signal, so you need another gateway between the bridge and RC to convert the signal back into IFI-format. I'm not entirely sure if the IFI controller needs to handshake with the OI, but if it does(Or if you want to send back any sort of telemetry), both gateways would need to operate bi-directionally.


EDIT:Actually it looks like the Luminary Micro device at least is capable of performing this gateway function That makes it a lot easier if you want to connect a pre-2009 OI to a pre-2009 RC.

[EricVanWyk]

Originally Posted by nathanww

For the router and bridge to understand the signal from youroperator interface, you'd have to convert it into TCP/IP networking data. A 2009 or 2010 control interface will do this automagically, but an older one based on the IFI OI unit will require a custom-programmed "gateway" to sit between the OI and the router.

The same thing applies in reverse on the robot end. The IFI controller can't understand your TCP/IP encoded signal, so you need another gateway between the bridge and RC to convert the signal back into IFI-format. I'm not entirely sure if the IFI controller needs to handshake with the OI, but if it does(Or if you want to send back any sort of telemetry), both gateways would need to operate bi-directionally.


EDIT:Actually it looks like the Luminary Micro device at least is capable of performing this gateway function That makes it a lot easier if you want to connect a pre-2009 OI to a pre-2009 RC.

Nathan -

I think the part he originally posted also performs this function. All of the serial to ethernet modules that I've played with have done so.

The real magic will be in a) configuring it and b) having the IFI system respond to it. I don't think he can plug into the radio port, he'll likely need to plug into an unused serial port.

Can the IFI systems run without an official radio plugged into the radio port to tell it that everything is ok?

[talltree357]

I was planning to utilize the tether port rather than the radio port. Do you think this would work? Any other advice you could give, I really appreciate everything so far.

[RyanCahoon]

An RS-232 cable will not work with the OI/RC link, because it runs over RS-485 (both the Tether and Radio ports). The common knowledge on CD seems to be that using RS-232 hardware with RS-485 a) will not work and b) potentially could damage hardware on both sides.

I played around a bit with controlling an IFI bot over wifi, but I took a different approach: Put both the OI and RC on the robot, as well as a laptop. Tether the OI and RC (so that the motors will un-disable), then connect the laptop to the Programming port of the RC to the laptop.

I then wrote some code to drive the robot based off of commands received over the serial port, and wrote a program to convert readings from a joystick plugged into the laptop into commands to send on the serial port. The jump to controlling over wifi can then be done by utilizing any serial port sharing software (this functionality is built into many remote-control software packages, such as Windows RDC), or you can write your own program to relay the joystick values over the network. You could also probably use the part you referenced.

The only functionality you don't get from this is the feedback LEDs and Dashboard port on the OI, but these features can be easily emulated by sending data the opposite direction.

--Ryan

[Joe Ross]

Originally Posted by RyanCahoon

An RS-232 cable will not work with the OI/RC link, because it runs over RS-485 (both the Tether and Radio ports). The common knowledge on CD seems to be that using RS-232 hardware with RS-485 a) will not work and b) potentially could damage hardware on both sides.

The radios are actually RS-422.

[Dave Flowerday]

Originally Posted by Joe Ross

The radios are actually RS-422.

...and the tether is RS-232 (though there are some additional signals that must be present for the tether to work).

[RyanCahoon]

Originally Posted by Joe Ross

The radios are actually RS-422.

Originally Posted by Dave Flowerday

...and the tether is RS-232 (though there are some additional signals that must be present for the tether to work).

Oops... should have looked a little farther I guess. Looking at the thread I found, this was corrected in a later post.

Thanks for the catch

I'm curious as to what project you're doing, and whether or not the Player/Stage software might be better suited to what you're doing... Their user list is quite responsive, and the system in general is quite friendly for development.

[Mark McLeod]

I used to control those from a PC via a bluetooth RS-232 adaptor through the programming port. No reason to leave the PC on the robot if you go Ryan's route. The adaptor you found or the cheaper TI/Luminary Micro module should serve the same purpose.

You can run the 2004 RC without the OI as well, by setting the team number to zero.
This may have been dependent on the Master code version, but that's easily checked and corrected.
Basically it'll always have the autonomous mode flag set, but your code doesn't have to pay any attention to it.
The lack of OI inputs don't matter if you control it from a PC, and the RC code works with the serial programming port just fine so you can accept controls that way without a problem.

If you do it this way you'll need to devise a fail safe way to disable the robot when it inevitably runs amuck during testing...

I don't know an easy way to replace the tether/radio with WiFi.

[talltree357]

Originally Posted by Mark McLeod

I used to control those from a PC via a bluetooth RS-232 adaptor through the programming port. No reason to leave the PC on the robot if you go Ryan's route. The adaptor you found or the cheaper TI/Luminary Micro module should serve the same purpose.

You can run the 2004 RC without the OI as well, by setting the team number to zero.
This may have been dependent on the Master code version, but that's easily checked and corrected.
Basically it'll always have the autonomous mode flag set, but your code doesn't have to pay any attention to it.
The lack of OI inputs don't matter if you control it from a PC, and the RC code works with the serial programming port just fine so you can accept controls that way without a problem.

If you do it this way you'll need to devise a fail safe way to disable the robot when it inevitably runs amuck during testing...

I don't know an easy way to replace the tether/radio with WiFi.

Mark, could you elaborate a little more on your process? This seems like it could be very useful.