Power splitter

Hello all,
So we are at a competition and we loose connection to VEXNet every single match and sometimes loose it multiple times. It’s gotten increasingly frustrating as we have no way to test our robot after we have spent tons of time on it. We have tried everything with our key and our batteries that have been previously suggested and we have a backup battery in. One team suggested a power expander though. I’m wondering, will this help with the disconnects? We have ten motors ( four on our base, four on our lift, and two intakes) all on one battery. I’m a little against it currently because it’s $50 that will be coming straight from my pocket but it it is worth it, I’m more than willing to do it.

Also, we are trying to find a kickstand that deploys when we lift our lift. We want it to be passive to a certain point though so it can go over the bump but once it hits the point where we start tipping, I want it to stop us tipping. If anyone has a design like that, it would be awesome to see it or just to have suggestions on it. Thanks all and enjoy your day.

What do the lights on the brain look like? Are you looking connection, or tripping your circuit breaker?

The only way a power expander will alleviate a VexNet dropout is if there is a large voltage dropout that kills the connection. However, a backup battery is designed to prevent just this… so, do you have a backup battery?

Yes, they do:

I already mentioned this earlier, but make sure the key might not be vibrating because it is loose. We had that problem before and had to put a piece of tape over the keys.

If it is a VexNet dropout problem, that might be fixed with the new 2.0 keys. Hopefully the info on the trade in program comes out soon.

For the controller, the lights will be all green then we will loose control. The lights will stay green for another second, then the third light will blink (I think yellow then red). Then for the brain, sometimes it goes to the single/ double flashing orange like when you first turn on the brain to get a connection to your controller. However, sometimes, we just get a single, blinking red light (I think it is the second light but I’m not positive). The issue can be solved usually by turning off the controller and turning it back on but if the brain has the red light, we are hosed. To be honest with you though, I have no idea. I feel like we may just be tripping the breaker because we seem to loose power when we are using our lift and driving at the same time. It never seems to be a jolt or anything either. It just seems to be when we use a lot of power. However, I’m not positive on that.

As Kevin said, we do have a backup battery. However, I’m not sure how charged ours was because we borrowed one from one of our other teams. I think it was charged though.

Ok we had tape and a rubber band to make sure the key was not moving today but we still seemed to loose connection. I’m beginning to lean away from the idea that we are losing connection because of the key due to the fact that we loose power when we aren’t jolting anything. Also, every other team from our school is having the same issue. We all use ten motors and draw lots of power without a power expander. But the disconnects just happen. I’m interested to try the new keys though. I hope they are better than the ones we have now.

Try to divide the power in half, like plug in all your drive motors into the power expander and for the rest plug it in the cortex! So it won’t kill the cortex itself by overloading it… :stuck_out_tongue:

That was actually what we were hoping to do but we don’t have any power expanders so I’m wondering what people think of them and if that could possibly solve my issues with VEXNet. It will most likely come out of my pocket so I just want to make sure it would be worth it.

My bad, should read more thoroughly…

What programming environment do you use and do you have an LCD display? Regardless of whether or not you have an LCD screen, you can monitor live voltage levels of your battery. Not the most helpful of answers to fix the dropout, but it could definitely help confirm the cause of dropout (which definitely seems to be voltage drain).

Meanwhile, have you made your lift and chassis as frictionless as possible?

Well they are quite expensive but do the job good, power expander is best for running your robot for a longer time also! :slight_smile:

Have you tried switching your VEXnet from the controller to the cortex, and tried syncing it with the orange USB cable? Your VEXnet may be experiencing issues…:o

Try with a new backup battery first, if you still have problems with that then the power expander will probably not help you. Using a discharged backup battery is sometimes worse than having no backup battery at all.

I was at your competition today, I was surprised that the school WiFI was not turned off, I was expecting lots of disconnect problems but my two teams didn’t experience any. You should have come by team 8888X and 8888Y pits and I would have taken a look at your robot.

We’ve been to 4 competitions this year, and at none of them has the wifi been turned off. Our teams have had zero disconnection issue other than those caused by bad keys. Once the exchange program hits and we get our new keys, we’ll hopefully have seen the last of them.

All good. We are using EasyC V4 and we don’t have an LCD screen. Ok how would I go about that? And we have really tried to yes. We took extra precaution in making our lift smooth and our base is similar. We could work on our base some more though.

Ya I was looking at them earlier so I want to make sure they are worth my money. And we haven’t. We can try that on Monday or Tuesday.

Ok will do this Monday or Tuesday too. Thanks.

I was at your competition today, I was surprised that the school WiFI was not turned off, I was expecting lots of disconnect problems but my two teams didn’t experience any. You should have come by team 8888X and 8888Y pits and I would have taken a look at your robot.
Oh that’s right! I didn’t put that together. We were really struggling today. We had a lot of things on our robot that were minimally tested and when added together really caused problems. Kind of a bummer but that was only our second tournament and we know all that we have to fix now. But anyways, honest opinion, what did you think of it? We want some feedback from teams just about how it went from your perspective. And ya I’ve been told we use a different frequency so we don’t experience wifi interference at all. Or at least minimally?

I probably missed it but do we know when this program will be started? And has anyone used the new keys in competition?

We had this problem when we had a lot of metal around the tip of our vexnet key. I don’t know if this is your problem, but if it is a power expander won’t help you. Although I do believe in general a power expander is a worthy investment. We have tried our robot with and without our power expander, and personally I think it performs better with it.

Ok great thanks. We will pitch the idea to our instructor then and see if he will buy it for us. If he won’t, we might as well.

I Dont have pictures right now, but i can certainly get some at engineering tomorrow. Our Robot has a passive anti-tip device, elastic powered, released by lifting the arm. We need to work with the elastics a little because we almost took a teammates finger off test deploying it the first time.

That would be extremely helpful if you wouldn’t mind. Do you have a six-bar? We had a really tough time with tipping at our last competition so I’m looking for a short term solution. We have a solid long term one I’m looking to reveal if we get to worlds :o. But this would be extremely helpful. Thanks!

Due to unfortunate circumstances including a factory defective phone, i wont be able to get any pictures in before tuesday, sorry. I tried to take them with my loaner phone, but it came out looking like an aluminum blob. And even that wont upload to my computer :confused: but yes, we do have a six bar. it needs some work, however, on spacing between bars. but it serves us decently. We finished our final testing on the anti-tip this week, and even placing it in the most vulnerable position (arm raised, front wheels on bump) and pitting our clubs strongest robot against it, it would not tip.

After a quick google search and a bit of creative thinking, i managed to get the pictures on my computer. The Samsung M360 does not allow cable transfer. The picture isnt the best, since to completely view the mechanism you’d have to take it apart. However, i can break it down step by step to explain it.

The first part is two small aluminum plates mounted to the bottom of the chassis with the green plastic slide inserts mounted onto that (one insert on each plate). Mounted via standoffs below the plate is a cut steel rail piece (larger width side is where it’s mounted, if that makes sense((also upside down)) with a hinge mounted onto the same side. the hinge is placed so that it can only swing open one way (the other direction is blocked by the side of the rail, so to properly place it the joint of the hinge must be right by that side) when the hinge hits the side of the rail, it cant open any more. thats lock numero uno.

The actual piece that keeps the robot from tipping back is two linear slide rails that slide on the plastic pieces. for them to lock, you have to screw a nut onto the outside of each one (so the nut then goes past the hinge, then cant go back). then boom! you’re untippable. but how do you keep it in the robot before the start of the match you say?

We have a standoff mounted on pillow blocks under our scoop to do that. the inside end of the slide rails has a cut bar connecting them, and then mounted on standoffs is a L-bar. the l bar catches on the scoop standoffs.An elastic band (or in the beginning for us, about five xD) streches from a standoff mounted on the chassis directly above the mechanism to the standoffs the l-bar is on. then when we raise our arm, and thus our scoop, the l bar is no longer caught on the standoff and it shoots back.

Sorry for the lengthy explanation, Im not too good at summarizing :stuck_out_tongue: I hope this helps though!

We have been having major disconnect problems. It would run fine at practice, but disconnect after only 30 secs. or so at tournaments. We got a new power expander and presto! We had league today and it ran fine.