I’m wondering this. Does anyone have any experience with making an RCX quit working? I’m working with a bunch of kids again this summer, and the eight we’ve used have all survived with no ill effects, but now I’m getting paranoid as we start to maximize the use of ours. A dead RCX would be rather hard to fix mid-camp without a replacement, but the replacement is pointless if we don’t really need it…
So, has anyone busted an RCX? What does it take to do it?
Are we talking the yellow bricky ones? If so, the following applies…
I think there are 3 at my house, all of which survived 4 years of FLL, and 2 years of sitting. All of them have freaked out at one point or another, but a simple firmware redownload stopped any funkiness which may have occurred.
I have had them lose the firmware though and not be able to redownload it, but we weren’t using robolab or the default firmware (which I assume you’re using).
Also, MSSM Summer Camps (same deal, just much much farther north), has a set of 6ish which have been used every summer for the past several years, all of which have survived.
Have never had a problem with them quitting. A new set of batteries and a firmware redownload seems to fix it (as mentioned above). If it breaks, I don’t think there is much hope in repairing it (either something hardware on the board broke/fried (in which you would have to replace the board (which is probably more than a new RCX)) or the processor went somewhere it shouldn’t (in which case… it’s stuck)).
I’ve had a total of 7-8 RCXs. Three of them have died. In the early RCXs(the ones with a power connector on the back, or bottom depeding on how you look at it) the bottom(green half) of the RCX had held the batteries, but the connection between that and the main board was nothing more than pressure between the board, and a belt piece of metal. I had two die because that no longer made connection. LEGO replaced both units without a question, and even let me keep both defective units.
I had another one die when we had a LEGO speed competition, and one of the robot smashed into a pole. That pushed the black piece on the front of the RCX into the main board, and damaged several components. That is the only RCX, after I had upgraded units, that had a problem.
The motors on the other hand are horrible. One FLL season we burned up 12 motors, again all replaced free of charge by LEGO. I believe in fours years of FLL I lost over 35 LEGO motors to random failures. HAVE EXTRA MOTORS!
I have never had a problem with sensor failures.
EDIT: If the RCX won’t load firmware, remove the batteries, and pres the power button 10-15 times. That will usually solve that problem.
General failures have more to do with batteries then with anything else. Make sure that all the battery compartments are clean, i.e. no leaked batteries, all contact points are clean, and no foreign matter anywhere (like cookie crumbs). Then check that all the contacts press against the batteries tightly. You should not be able to turn the RCX over and have any batteries fall out. You might have to use a small screwdriver to pry some life back into the contacts. When in doubt make sure that the firmware is properly loaded or load it again. One of the students might have dropped the RCX pushing one of the batteries out of alignment for long enough to corrupt the firmware. IR illuminators in use on security cameras can play havoc with downloads so watch for cameras in your class room. If you have checked all of the above and you still have a problem, look for dings in the case (rounded corners, cracked LCD, etc.) indicating a drop. There may be no coming back from a cracked circuit board. As you know, the motors don’t survive a drop either. If you can’t easily back crive a motor, it is likely to have been dropped which either bends the shaft or deforms the motor case.
I have never had a problem with my RCX. The only problems I have had is a messed up touch sensor (came like that) and what I’m going to build next. The other thing is that I don’t usually watch my battery power. Always keep your program files backed up, otherwise, you are SOL.
I don’t think I’d worry too much about the Mindstorms RCX bricks.
I’ve been involved with FLL since 2002, and I’ve never seen any of the students I’ve mentored break any of them. I’ve seen them drop them (multiple times!), put all the batteries in the wrong direction, plug motors and sensors on the wrong ports, plug the motor output onto the sensor inputs, and the list goes on and on. (Leave it to 12-year old kids to find as many ways as possible to try to void the warranty…) All stories short, they all survived.
Generally, the motors are pretty robust as well. Only twice I’ve seen kids drop them and shear the shafts off the motors, and once there was a kid who would always try to attach wheels to the motor and manually spin it as fast as possible (stripping out the gears on the inside). In normal use, as long as they’re geared down correctly, they should never burn out.
I had a fence climbing bot fall 15 feet onto a concrete surface without any serious damage. The same RCX has survived 7 years of FLL on a team that:
-likes fast robots
-uses the “ram into wall to correct angle” approach to self correcting.
In general, mindstorms components are quite strong. I’ve only had one out of something like 25 motors burn out, and that was in an experiment to test the strength of the motors that looked kind of like this The only real problem I’ve had is with the toutch sensors jamming or becoming unable to detect a push after repeated, strenuous use, such as the wall hitting described above.
In my experience, RCXs acting weird are more than likely IR issues. I have seen robots at FLL competitions do some REALLY weird things due to IR focusing cameras. As others have said, changing batteries or realoading firmware usually solves the problem
Yeah, I once spray painted a bunch of touch sensors (I thought I completely covered the button part), and apparently some of the paint got inside… because the sensors stopped working. But that’s not normal classroom use…
I’ve seen the “impact test onto concrete” before, on the team I mentored, and the RCX worked. Another team tell about the “punt test”–apparently the kid who did that was told to take the RCX out before doing that again, but the RCX survived.
Batteries and firmware–change the batteries fast, you don’t need to reload the firmware.
IR: We had issues our first year with an FLL team. The program worked right sometimes but not others. Then one of the dads shut off his camera’s autofocus, which used IR ranging. The robot worked much better, for some odd reason. (Also, there are LEGO remotes. Keep those hidden/unpowered.)
way back in 2002 was the first year nationals hosted a lego competition, and low and behold our lego team was invited to compete. We packed our bot into hard plastic cases and were on our way. Someone was supposed to take the robot out of the big box that was being checked on to the plane.
No one did…thus, the robot underwent the trip on the plane from the luggage compartment. When we got to florida, we opened the box only to find a pile of lego pieces and an RCX…the RCX, worked flawlessly…even all the programs were intact…the robot, well lets just say we spent a considerable amount of time that night rebuilding her.