Switching the Channel for Competition

[Billfred]

Alright, I think I'm up for building a dongle for our team. But since I'd rather not fork over $1200 for a new OI, I figured I'd ask and make sure my wiring scheme would work. It's attached. (I'm sorry about the .bmp--my computer is a pain in the booty.)

Any tips for building one (other than to be careful and don't short anything out)?

[KevinB]

Originally Posted by Billfred

Alright, I think I'm up for building a dongle for our team. But since I'd rather not fork over $1200 for a new OI, I figured I'd ask and make sure my wiring scheme would work. It's attached. (I'm sorry about the .bmp--my computer is a pain in the booty.)

Any tips for building one (other than to be careful and don't short anything out)?

This is perfect. When I build them, I use a 3-position switch for the Disable and Autonomous function instead of using two switches. It will work fine with 2 switches though.

It's really not difficult to make ... and even if you do screw up, chances are you wont completely fry your OI. I've accidentally shorted the wrong pins a few times, and we've never lost an OI. We had one start acting weird ... but a reboot fixed it right up.

Good luck.

[Biff]

Originally Posted by Ian W.

We wanted some blue LEDs flashing, so I jammed a paperclip in the right pins (I looked them up), played with the channal dipswitches, and got it set to 13. Now we have blue LEDs.

It's not that hard, just don't do anything dumb ;-).

Real risky with the paper clip, We lost a OI CPU messing about with not up to specs wiring practices. Some of the pins on the Comp port go directly to the CPU in the OI and it clearly states that you fry things messing with the port and there is no warrenty. More than 150 dollars including the overnight shipping. As the Innovation First Service Tech said, triple check your wiring before stabbing on to the Comp port.

[Biff]

Originally Posted by Billfred

Alright, I think I'm up for building a dongle for our team. But since I'd rather not fork over $1200 for a new OI, I figured I'd ask and make sure my wiring scheme would work. It's attached. (I'm sorry about the .bmp--my computer is a pain in the booty.)

Any tips for building one (other than to be careful and don't short anything out)?

There is a doc on the Innovation First Web site that lists the pin outs. I'm having trouble getting to thier site right now so I will attach the PDF

[Billfred]

Thanks for the input.

I noticed on my sketch that I just had 8 and 12 hooked together directly for channel access. IFI's has a switch to enable/disable this. Is there any advantage either way?

And I'm just thinking out loud--if those are all the pins one needs to do autonomous and disabling and channel setting, how hard would it be to create a rudimentary arena controller? Just run the wires for four dongles to one central spot, perhaps add a timer to the disable circuit, and bada-bing! (I figure that even the channel -shouldn't- matter, since the RC checks for team number as well. Of course, it wouldn't hurt to give each robot their own channel in matches.)

Now for my final question: where on earth do you get those DB15 connectors? I checked my local Radio Shack, then their site. No luck either place.

<edit> And I'm just curious, since my team is always looking for easy sources of bling (is reminded of the team's initial idea to stick strobe lights in the metal 2x4s)...is there enough power going through these pins to send juice to an LED (or similar device) indicate that said pins are connected? </edit>

Thanks again!

[KevinB]

Originally Posted by Billfred

Thanks for the input.

I noticed on my sketch that I just had 8 and 12 hooked together directly for channel access. IFI's has a switch to enable/disable this. Is there any advantage either way?

There is absolutely no advantage to using a switch ... don't use one.

Originally Posted by Billfred

And I'm just thinking out loud--if those are all the pins one needs to do autonomous and disabling and channel setting, how hard would it be to create a rudimentary arena controller? Just run the wires for four dongles to one central spot, perhaps add a timer to the disable circuit, and bada-bing!

You are correct, this would be reasonably easy.

Originally Posted by Billfred

(I figure that even the channel -shouldn't- matter, since the RC checks for team number as well. Of course, it wouldn't hurt to give each robot their own channel in matches.)

The channels absolutely must be different. Even with the team number check, the packets will still interfere with each other.

Originally Posted by Billfred

Now for my final question: where on earth do you get those DB15 connectors? I checked my local Radio Shack, then their site. No luck either place.

You should have received several in the Kit of Parts. Otherwise, check www.digikey.com

[Billfred]

(checks digikey)

Good heavens, that's a lot of parts. Can anyone point me to a particular item number or some other method for the non-electrical genius?

And I know I asked this before, but I've got a hunch it got overlooked: Is there an easy way to hook some sort of LED or similar object that indicates that a certain switch is on?

Thanks again!

[KevinB]

Originally Posted by Billfred

(checks digikey)

Good heavens, that's a lot of parts. Can anyone point me to a particular item number or some other method for the non-electrical genius?

Digi-Key Part Number 215M-ND.

Originally Posted by Billfred

And I know I asked this before, but I've got a hunch it got overlooked: Is there an easy way to hook some sort of LED or similar object that indicates that a certain switch is on?

Thanks again!

Yes, this is possible. I don't know the specific details, but I know it involves using Pin 1 to get power.

[Mark McLeod]

Originally Posted by Billfred

Is there an easy way to hook some sort of LED or similar object that indicates that a certain switch is on?

A safe method is to simply use a DPDT switch from Radio Shack and a 9 volt battery ignoring the power pin altogether. Hook up the competition port pins to one side of the switch and an LED/resistor/9volt to the isolated DPDT pins on the other side of the switch. When the switch is "on" the LED will also be "on", but the LED is actually on a separate circuit powered by the 9v battery.
This is probably the normal method most teams use for LEDs on the OI.

[Billfred]

Originally Posted by Mark McLeod

A safe method is to simply use a DPDT switch from Radio Shack and a 9 volt battery ignoring the power pin altogether. Hook up the competition port pins to one side of the switch and an LED/resistor/9volt to the isolated DPDT pins on the other side of the switch. When the switch is "on" the LED will also be "on", but the LED is actually on a separate circuit powered by the 9v battery.
This is probably the normal method most teams use for LEDs on the OI.

Okie doke...so now my wiring diagram has grown to this...(see attached)

A note on the switches...I was thinking, and while it's smart to have a nice, big, mash-the-red-button-to-stop-that-robot disable button, it isn't as good for autonomous mode, as then if you mash it, you'll probably be disabling the sucker anyways. So I figure that the disable switch will be alternate action (either DPDT, or perhaps two separate switches activated by the same button), and then the autonomous switch would be more light-switchy in activation. (I wired in the LED so that you can tell pretty easily whether or not the disable switch is activated without having to decipher the OI. Maybe I'll make it a buzzer, to make it really obvious. Saves having to troubleshoot the stupid stuff, I figure.)

Although, given my tackling by our robot when it leapt into autonomous the last build night, I'm tempted to take a cue from our ROTC corps' F-16 simulator and make it like the nuclear consent switches--you know, lift the flap that holds it off, and THEN you get to flip the switch and launch the nukes. Or start autonomous mode. Your choice.

Switch choices and ergonomics of the box aside, any comments on the updated wiring scheme?

[dez250]

i would suggest putting a resister in between the 9volt battery and the positive lead on the LED. Also since LED's are a diode, LED's have a distinct positive lead. Normally the longer lead coming from the LED is the positive lead.

[Mark McLeod]

Originally Posted by Billfred

Switch choices and ergonomics of the box aside, any comments on the updated wiring scheme?

Wiring looks fine, just make sure you are looking at the correct side of the connector when you wire it together. The view you have is looking at the front of your Digi-key soldercup connector, not the back where the wires connect.

[edit] LEDs with integral resistors came in the robot kit, or Radio Shack carries them. As dez250 says you'll need a resistor in series or you'll burn out the LED rather quickly.

[ahecht]

Originally Posted by Billfred

And I'm just thinking out loud--if those are all the pins one needs to do autonomous and disabling and channel setting, how hard would it be to create a rudimentary arena controller? Just run the wires for four dongles to one central spot, perhaps add a timer to the disable circuit, and bada-bing! (I figure that even the channel -shouldn't- matter, since the RC checks for team number as well. Of course, it wouldn't hurt to give each robot their own channel in matches.)

You're right, it is quite simple if you have teams set their own channel. For this past year's miniFIRST competition, we just wired up a connector to some telephone line, and had a three position switch for autonomous and disabling on the other end.

It is even possible to build a more complex system. The person who wrote the current official FIRST scoring software is an alum of Team 190, and while on the team he was working on making his own system that would interface with his scoring software. I don't think he finished it before he started working for FIRST, but it definately looked possible.

[Dave Flowerday]

Originally Posted by ahecht

It is even possible to build a more complex system. The person who wrote the current official FIRST scoring software is an alum of Team 190, and while on the team he was working on making his own system that would interface with his scoring software. I don't think he finished it before he started working for FIRST, but it definately looked possible.

It's not hard to do. We've made a system for our practice field that is computer controlled and allows individual stations to be controlled, as well as real matches with all 4 starting in autonomous then transitioning to normal mode at the correct time. There's a big time display on a monitor so the drivers can get used to watching the clock, and we even have the sounds nicely integrated and all. It makes for some fun (and realistic) practices!