Send-Home Devices

We were almost disqualified at a local scrimmage when our alliance partner used a send-home device. Use of this mecahnism does seem problematic and there’s always the possibility of the opposition purposefully entangling themselves in order to disqualify the other alliance. What do you think about this? Should these devices even be used?

We had a similar issue, see my other thread (

I can’t find ur other thread! Link directly!

It would be stupid to discualify your opponent BECAUSE all that matters is the total number of points you get not whether you win or the opponent wins (in the qualifings)

Send home devices seem pretty risky to me. I would not use one.
AS for getting a DQ for the other team, in the elimination rounds your score is based on your score not the other teams. That is just in the seeding rounds I think.

We have one. It shouldn’t be an entaglement issue…
1/4" (maybe 1/8") PVC in 4 foot sections. Think that will pass the check in entaglement plausibility test. As well as I think it won’t get tangled on the field.
We’ll see.

*Originally posted by Wetzel *
**We have one. It shouldn’t be an entaglement issue…

To comply with the philosophy of full disclosure of robot abilities (everyone should read this thread), we should point out that “we have a send-home device” is slightly different than “we have a send home device that we have actually tested and are highly confident actually works.” Our “mouse” (or the “rat” when we weren’t in a good mood) went in to the crate having been tested as a stand-alone subsystem, but never fully integrated with the rest of the robot. So we make no claims about how well it really works - yet (maybe that should be extended to the rest of the robot as well???).

Many on our team really wanted to finish integrating all the parts of the robot and actually test all the systems. But if we did that then we would not have anything do on Thursday at the Richmond Regional! :slight_smile:


Only two things are infinite, the universe and human stupidity, and I’m not sure about the former.
- Albert Einstein

we have a send home device made of sections of linked 1’ square tubular aluminum sections which pull out 30 feet. It has been thoroughly tested and it works like a dream, reliably. This “arm”, while it runs on small wheels along the floor, is fairly rigid and should be high enough above the carpet not to be considered an entanglement. As described below- it is flimsy, as any arm 30 ft long deploying from a 3 ft box would be!. It is also easily changeable between rounds and others have been made to replace it should a rambunctious opponent get malicious.

In FRC Engineer update 144 I quote- “A telescoping arm, given sufficient lack of sharp features etc, would likely not present entanglement but might prove flimsy and unreliable. The ultimate determination of what presents a risk of entanglement is made by inspectors at each event”

To me it sounds like the INSPECTORS who clear the robot for competition will not let it enter the field if it is deemed an entanglement. It also sounds like there will be a great deal of inconsistency from regional to regional. At the NH kickoff Kamen offered “Kamen points” for a robot which could score in both end zones. We can do that easily

If there is a disqualification for us we do have an alternative device to replace the arm. But quite frankly it will make us play another strategy which I am CERTAIN our opponents will not like.

I would like to know whether all these judges at the pregame events we’ve been hearing about are actually FIRST certified inspectors and are totally familiar with all the fine points the FRC engineers gave us during the season?

Should they be used? Certainly!! Unless you have another way to simultaneously control two goals on the field and get the additional 10 pts.

My $.04 worth


We are our own send home mouse bot???

guys I have to say I was a little disappointed with how the entanglement rulings were made. Our team spent many hours making, what everyone an SBPLI will agree, is a rocking fast 18 foot arm with absolutely no possible entanglements. Then we get there and see loose wires and such. I thought they would have been DQ’d for sure but guess not. I think nationals will be much more strict however I have heard rulings were equally lax at KSC and Virginia

What happens when a red alliance robot blocks the effort of a blue alliance robot to successfully maneuver their send-home device into the home zone in the closing seconds of a match? Assume that this move is strategically sensible, pointwise, in that particular match, be it qualifying or elimination.

Do you think red is attempting to entangle in blue’s device and draw a DQ for blue? Would you protest this action if you were blue? If blue’s “mouse” ran into the mouth of a red “ball eater”, what happens?


My team’s bot’s send-home is a roll of duct tape and a metal roller. The duct tapwe is affixed to the carpet, and it’s light-adhesive blue painter’s duct tape, so it’s easily removed from the carpet during the post-match seconds. It doesn’t pose any entanglement threat, no more than the floor itself, and doesn’t actually damage the game surface. Legal? I think that’s for the judges to decide, but I’d like feedback on the point.

I hope you are joking! The manual specifically stated that no device may adhere to the carpet. This is most definatly illegal. In essance, you are using the adhesive to gain traction on the carpet (so your tether will not get bunched up when driven over), so you are in direct violation of rule M11. Plus, the blue painter’s tape is masking tape, not duct tape.

blocking of a mouse is certainly legal. I can roll my bot infront of yours, and infront of your mouse. I couldn’t entrap it, say pin it to a rail or cage it, but I can certainly make it turn. this occurred in our regional when a team stopped another teams mouse and the judges didn’t bat an eye.


Feel free to block a “mouse” - but doesn’t that defeat the purpose? The mouse doesn’t get 10 pts but neither do you so it is a wash.

If in the last few seconds you decide to race home it is a matter of who is faster. Sounds good to me.

Of course if you can pick it up and drag it home with you there is a definite bonus.

Just my $.02


I was really dissapointed about the whole entanglement rule. There was so much fuss on the FIRST Q&A message board with regards to entanglement that our team decided it would be safer to design a telescoping pole than try and design something with a cable and wires. Had we known it was going to be like this we probably would have tried a couple of the mice type ideas instead.

-John D.

That is kinda what happened to Team 302 in one of their qualification matches. They have a 4" wide x unknown length of lexan that they can deploy behind their bot. One match they deployed the lexan only to have another team intercept it and bend it back into 302’s opponent scoring zone, thus scoring 10 points for the opposition. They lost the match by 2 points :o

Wayne Doenges

I admit that stopping the mouse it pretty silly, especially because if a team can drag bundled wires they can certianly make a steerable mouse, which will inevitable be more maneuverabke than your bot. However if our team has a reach home device. . .(and we do) then we could stop a mouse no prob, or atleast make it steer around us.

I am rather suprised that FIRST is allowing many of the send home devices, I now see a bunch of teams in the pits adding upside down tape measures which is a real rip for all of the teams that spend so much time designing devices that were not only somewhat robust parts of the robots but also not entangling. As for the mice that is just the same, dragging a steerable coil of wire seems to be just what first didn’t want to see on YAHOO but yet there are so many out there. We don’t have any type device but if we had an elaborate one I can bet you we would be upset at all of the gray area ones out there. We didn’t have the weight or time to do it so we didn’t, but if I would have known a tape measure was good enough it would have been easy to ad. FIRST what is YOUR say on these devices for real???!!!

I’m just curious about what will happen if a robot drives over the tape measure or bundles of wires and gets entangled by them. From what I’ve seen from the telecasts (haven’t gone to our regional yet), there have been few if any DQs.

Another interesting thought - we have a pretty powerful ball lift mechanism that could effectively “eat” a mouse (assuming we can catch it) - I’m going to be really upset if we get DQ’d for malicious behavior when we are just trying to play the game against an illegal mechanism.

Basically, I think the whole tethering issue has gone too far. FIRST made the rules, explained them on the website (causing us to bypass building a mouse) - and now are not enforcing their rules.