Okay we have had this issue for 2 years, and our scissor lift just now started doing it when we were testing. Basically you will be driving, and the microcontroller literally dies but when I like push the robot or gently kick the base, it turns back on. And it will repeat itself, we lost a lot of competitions we should have won last year because of this issue and we haven’t been able to find a culprit.
Are you using the older black VexNet keys or have you upgraded to the white ones yet?
The new ones, we used the black last year and I know those suckedddd. It was dieing today on both white vexnets and when plugged in with cord.
Fresh batteries and everything btw
Fresh 9 volt backup battery, too? I’m just thinking of the obvious stuff first.
Has this problem been happening with the same cortex these past 2 years?
Check the connection between your cortex and battery. Power on your cortex and controller and GENTLY wiggle the battery plug connected to the cortex. If the power drops out, then your plugs are worn out and you either need a new cortex or a battery extension. Another way to test this is to wait until you have another drop out and then wiggle the battery connector connected to the cortex. We have the same exact problems with our old cortexes. If you don’t have enough money or time to replace the cortex, use foam or rubber bands to make a cushion for the cortex and reduce vibrations. The battery plug will vibrate less and thus have a lesser chance of disconnecting.
^^^ This
We had the same problem. The solder joint on the circuit board can crack and give that problem. We had one sent back to vex for repair and it solved the problem.
Because of this, we now never plug our battery directly into the cortex…it wears the heck out of that connector. We now leave an extension cable plugged into the cortex all the time to prevent that wear.
Our cortex is brand new, we have like 15 i believe but opened a new box just to get rid of them problem and well it came back. We don’t have a back up battery on because it was causing weird issues with the bot.
What sort of issues? If the Cortex is new, and you’ve got the newer keys and you’ve seen this sort of problem with other Cortexes and you’ve not been using your 9 volt battery on them either like the Fairy Battery Momma told you to… well, I’m just saying.
And this is why I always make sure to check the forums. Wouldn’t want to miss out!
Well…our robot last year did have a backup at all times on it and it still did it.
What extension cable are you talking about? Sounds wonderful
Plugs into the cortex, then battery can be changed without so much wear on the cortex connection.
:eek:Amazing I will try some of tips everyone gave me tomorrow. I got 3 hours to figure it out until comp.
If the weird issue is that the Cortex remains powered sometimes even after you turn it off, that’s just life in the big city and you need to unplug the 9 volt to shut down the Cortex sometimes.
It was causing mixed signals, I already knew about unplugging after a match because the cortex would remain on if you didn’t.
Would you mind elaborating on this? I don’t mean to pester you about it - it’s just that I always like to know about problems in case I encounter the same issue.
I don’t remember much about all the things it was causing as it was almost a year ago but I remember it was causing the battery on the robot to go full red if the 9V was close to low.
It would cause the robot to restart if the 9V “died” we would put in a fresh brand new battery, and it would just go to red on multiple microcontrollers we tried this and got the same feedback.
It was mainly where we would plug in 9V, it would act weird and we would unplug it, and the robot would act like it should. So we voted to not use a 9V again on the robot basically.
To sum it up, it made the cortex act strange in ways it shouldn’t and we knew it could only be the 9V.
sorry I can’t go in detail, it was so long ago and not one of my top priorities at the time to remember.
Then I believe the problem is with your battery plugs and not your cortex. Even though the connectors are connected, the wires inside the connectors might not be making a reliable contact. Next time a drop out happens, try pushing the battery wires into the connectors. It’s difficult to explain but when a battery is plugged into a cortex, shove the wires, not the white battery connector, deeper into white plug.
I will try that next time it happens to see if it’s that. We will be testing all day tomorrow so it should happen.
In Sack Attack our cortexes became a physical demonstration of Murhpy’s Law (6 cortex replacements over the course of the season, all but 2 happened in competition). Some things that happened to our cortexes that haven’t been mentioned here:
-Worn power switch. According to our RECF support guy, the on/off switch on our cortex was worn and didn’t always complete the on circuit when it was switched on. This caused frequent disconnects that would often disable the robot anywhere between 2 seconds and 2 minutes.
-Worn USB port. If the USB port becomes slightly damaged over time then it won’t maintain a stable connection with the VEXnet key. This can cause dropouts as well.
Some things that WON’T require you to replace your cortex or send it to VEX:
-Corrupted firmware in the cortex and/or controller. Firmware does strange things sometimes. Try redownloading it into your cortex, controller, and keys.
-Bent battery leeds. It’s possible that the pieces of metal the connect to the battery (or the prongs on the batteries themselves) are slightly bent and this can cause you a problem. If you’re VERY delicate and careful you can fix this with a small pair of needle-nose pliers. Perhaps ask your coach to do it just to be safe.
If worst comes to worst, we found that the larger clubs at competitions sometimes have an extra cortex on hand, and if you ask nicely they may let you borrow it. It can’t hurt to ask. Larger tournaments sometimes also have RECF tech support volunteers that are experts on this and can help you troubleshoot.
Good luck!
Thanks for the info!
I will say this, when we were testing last night ,the 15 second autonomous, when it ran into the peg to pick it up, the cortex would stop for 1 second and it would restart the autonomous program again.
#tomanycommas