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Unread 02-16-2004, 06:17 PM
greencactus3 greencactus3 is offline
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mounting the electronics

a couple questions from a rookie team..

is it really BETTER to have them mounted on a non insulating surface?
is it better to have them mounted on a board that is easily deattachable from the robot?
is using velcro to mount each individual component a good idea?
is it not a good idea to mount them to our frame directly using velcro?(our frame is aluminum)
how easily accessible should they be?
is it a bad idea to need to flip the robot over to take out the battery?
has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?
how what gets HOT? the motors..... the victors? well they already have fans on them...

well anyways, please tell us what is BAD. and what we need to worry about or what we need to be careful of or what has to be however (other than whats on the manual)

just don't want to do anything wrong! thanks!
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Unread 02-16-2004, 06:28 PM
Tom Bottiglieri Tom Bottiglieri is offline
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Re: mounting the electronics

Would i say it's better to mount everything to a board? NO
well then again, we have a wood base.
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Unread 02-16-2004, 06:33 PM
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Re: mounting the electronics

Personally, I think an insulating surface is better for electronics - there is less of a risk of a short if a wire falls off. That being said, aluminum is stronger than plexiglas and most other insulating surfaces.

As for easily detachable... Yes, it is definitely a good idea to make all wires as accessible as possible. A detachable panel may be a good thing.

Velcro, in my opinion, is a very bad idea. It is not strong enough for what the bot will have to endure during the match. If the velcro falls off, so does your RC/speed controller, then the wires are going to be ripped off, and you'll short the battery. Definitely not a good idea

Motors and fuses going bad... It could happen, but it did not to our team. You can check fuses with an ohmmeter to see if they are ok. As for motors... You can bring spares if you want (it would be the best thing to do), but if you cant get spare motors, FIRST should have a limited supply at the competitions.

The motors should not get hot if your gear ratios are right. If they do get hot, a fan will not solve the problem. There was already a thread about this.

Of course, anything could go wrong at any time Just do your best to avoid obvious mistakes.
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Unread 02-16-2004, 06:34 PM
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Re: mounting the electronics

[quote=greencactus3]a couple questions from a rookie team..

Quote:
Originally Posted by greencactus3
is it really BETTER to have them mounted on a non insulating surface?
Much less can go wrong from uninsulated wires and connectors if they can't touch something big and conductive

Quote:
Originally Posted by greencactus3
is it better to have them mounted on a board that is easily deattachable from the robot?
I can see the advantage of this, but in 8 years I've never felt it was worth the time to do so. Especially since you are this late in the season, I wouldn't try.

Quote:
Originally Posted by greencactus3
is using velcro to mount each individual component a good idea?
Personally, I like bolting them down better. However, This year, about half our components are velcroed down. When used in large quanties, velcro is quite strong on a horizontal surface. I wouldn't put it on the edge of mounted vertically with velcro, though.

Quote:
Originally Posted by greencactus3
is it not a good idea to mount them to our frame directly using velcro?(our frame is aluminum)
see above about mounting to a conductive surface. Also, if it is on the exterior, I'd be worried about other robots running into you.

Quote:
Originally Posted by greencactus3
how easily accessible should they be?
Seeing that you are a rookie team, you more then likely will have electrical problems that need to be solved quickly. They don't need to be in open air, but it also shouldn't take more then a minute or two to get to them. You also shouldn't have to pull an contortions to work on them.

Quote:
Originally Posted by greencactus3
is it a bad idea to need to flip the robot over to take out the battery?
the battery has to be easily accessible, per the rules. You also have to demontstrate this to the inspectors. I do not beleive this meets that criteria.

Quote:
Originally Posted by greencactus3
has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?
If you get metal in the speed controllers, they will release the magic smoke.

Quote:
Originally Posted by greencactus3
how what gets HOT? the motors..... the victors? well they already have fans on them...
That's pretty much it.

Last edited by Joe Ross : 02-16-2004 at 06:36 PM.
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Unread 02-16-2004, 06:35 PM
greencactus3 greencactus3 is offline
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Re: mounting the electronics

Quote:
Originally Posted by OneAngryDaisy
is it better to have them mounted on a board that is easily deattachable from the robot?- Yes. If you add a new motor or component you won't want to bend over the robot for 10 minutes shifting wires-
how? a couple bolts?

Quote:
Originally Posted by OneAngryDaisy
is using velcro to mount each individual component a good idea?-NO! a direct hit could knock something off, imagine losing your entire left drivetrain thanks to a collision-
again, how? i don't think glue'll work. or wait were there hole for bolts on each one?

Quote:
Originally Posted by OneAngryDaisy
is it a bad idea to need to flip the robot over to take out the battery? Um.. yes... flipping over 130 pounds of metal isn't pleasant, and in the playoffs you'll have to replace it often-
or how about crawling under and replacing? i don't know how big the pit area is... well, our robot is quite high off the ground and it might be nice to have more weight below than above. not worried itll flip or anything but just MIGHT be better
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Unread 02-16-2004, 06:43 PM
Venkatesh Venkatesh is offline
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Re: mounting the electronics

1. Is it really BETTER to have them mounted on a non insulating surface?

This year, we constructed our electronics "deck" to be removable from the robot, so a board made sense. If you are careful with your wiring, you don't need a board at all. It has made things easier for us, though.

2. Is it better to have them mounted on a board that is easily deattachable from the robot?

In the hectic scene of the pits, will you have time to remove a deck, check wiring, check code, recheck wiring, and recheck wiring again, and then reinstall the board? Remember the number of devices that much be connected. We tried using terminal blocks to keep all the wire that interfaced the board with the 'bot separate, but our board ended up affixed.

3. Is using velcro to mount each individual component a good idea?

Honestly, I wouldn't trust velcro for components so critical. However, if you are able to construct stable mounts with velcro, and happen to have spare components, go for it. Velcro knots and meshes might be strong enough.

4. How easily accessible should they be?

Anything that can go wrong will. Robots that should move won't. Robots that shouldn't, will. Speed controllers will explode, resembling small atomic bombs (really), relays will jam, etc. Accessible components are a good idea.

5. Is it a bad idea to need to flip the robot over to take out the battery?

Can you (1 person) change a battery in an emergency in under 2 minutes? If so, good. Personally, I like to have the battery as accessible as possible, especially if a robot frame is aluminium. In the off chance of a short, you can do something. However careful wiring can eliminate that problem.

6. Has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?

We have had speed controllers (victor 883s) which appeared to work, but the electrolyte in the capacitor had dried up, and they didn't actually power the motors. We have never had problems with relays, spike red or blue. In fact, we have never even blown a fuse on the relays. Our main problems have been more physically oriented (physical damage, etc).

7. how what gets HOT? the motors..... the victors? well they already have fans on them...

The victors get hot, but not very hot. I believe that the Victors act like the Tekin Rebels, generating the greatest heat at low speeds. I'll have to check that sometime. Motors (especially the drill) get very hot after significant run times. Last year, we had a drill motor reach a temperature where they were far too hot to touch, and that was after roughly 10 minutes of running. I personally like to cool them, but I don't see too many robots that do so.
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Unread 02-16-2004, 07:32 PM
greencactus3 greencactus3 is offline
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Re: mounting the electronics

Quote:
Originally Posted by Venkatesh
We have had speed controllers (victor 883s) which appeared to work, but the electrolyte in the capacitor had dried up, and they didn't actually power the motors. We have never had problems with relays, spike red or blue. In fact, we have never even blown a fuse on the relays. Our main problems have been more physically oriented (physical damage, etc).
how about 884s? i think thats what we are using. also, a red spike and a blue spike? is that the difference in the letters? whats the REAL difference? is one better than another? please explain
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Unread 02-16-2004, 07:54 PM
OneAngryDaisy OneAngryDaisy is offline
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Re: mounting the electronics

Quote:
Originally Posted by greencactus3
how? a couple bolts?


again, how? i don't think glue'll work. or wait were there hole for bolts on each one?


or how about crawling under and replacing? i don't know how big the pit area is... well, our robot is quite high off the ground and it might be nice to have more weight below than above. not worried itll flip or anything but just MIGHT be better
For mounting the board- yes, we usually have a lexan board bolted to our robot so whenever something needs to be changed our programmer can whip it out. However, after 'building' season ends, we usually leave it intact.

All of the components should have holes for attaching small bolts.

about crawling under, if you guys make a cart then you shouldn't have to crawl under.. but thats a big if, we didnt even have a cart our first 3 years :/
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Unread 02-16-2004, 08:02 PM
KenWittlief KenWittlief is offline
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Re: mounting the electronics

Did FIRST change the rules about using tape? I dont think you can use velcro tape (sticky on one side) on your robot - you can use velcro belts or loops to hold your battery in - but last time I read the rules the only 'tape' you could use was electical tape, and not to hold things together, only for insultation.
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Unread 02-16-2004, 08:07 PM
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Re: mounting the electronics

is it really BETTER to have them mounted on a non insulating surface?
Yes. Last year, our chassis was a sheet of 1/4" aluminum. We mounted the electronics directly to it, and found it very annoying - it increases the likelihood of accidental shorts, and it means that you have to either tape up or remove sensitive components before drilling holes or making modifications. It's more trouble in the long run than simply making a separate electronics board out of non-conductive material.

is it better to have them mounted on a board that is easily deattachable from the robot?
That depends on how accessible the board is. If you can reach it easily without having to dig through everything else in the robot, not necessarily. If you can't fix wiring easily with the board installed, then make sure you can detach it quickly.

is using velcro to mount each individual component a good idea?
No. The force of bent wires trying to unbend themselves can be sufficient to force components loose from even the heaviest Velcro. We tried this in 2001, and it made a mess. The electronic components all come with holes drilled in them so you can bolt them to things. Use them.

is it not a good idea to mount them to our frame directly using velcro?(our frame is aluminum)
Aside from the usual Velcro concerns, doing things this way makes power distribution a nightmare. If you mount your electronics to their own board, you know that you won't end up needing to mount other things to that, and you won't have to rework your wiring all the time when changes are made to other things.

how easily accessible should they be?
Obviously, you need to be able to access the main breaker fairly easily. For troubleshooting and maintenance purposes, it's a very good idea to make all the other components as accessible as possible. Last year, our electronics were very poorly organized, making it difficult to troubleshoot problems and repair or replace things when necessary. After that, I made sure to make this year's board as neat and accessible as possible, and it's been a dream to work on so far.

is it a bad idea to need to flip the robot over to take out the battery?
Yes. The battery is something that you will want to be able to access very quickly and easily.

has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?
Battery shorts can make wires melt. Victors are always happy to vent their magic smoke. Crimp connections can fail. Assume everything is unreliable until proven otherwise.

how what gets HOT? the motors..... the victors? well they already have fans on them...
If your gear ratios are good, the motors shouldn't get TOO hot under normal circumstances. The Victors already have their own fans, but you might want to consider putting additional fans near them if your electronics are enclosed in an area that is not well-ventilated.
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Unread 02-16-2004, 08:50 PM
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Re: mounting the electronics

Quote:
Originally Posted by greencactus3
how about 884s? i think thats what we are using. also, a red spike and a blue spike? is that the difference in the letters? whats the REAL difference? is one better than another? please explain
The difference between the 883's (discontinued) and 884's is that the 883's have a larger deadband around the center (they provided control of approxmately 10-100% power in each direction, whereas the 884's provide ful 0-100% control in each direction).

The Spike Reds (long discontinued) defaulted to the "on" output state on both channels unless they were told by the RC to be "off"; the Spike Blue defaults to the "off" output state (safer).
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Unread 02-17-2004, 06:39 AM
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Re: mounting the electronics

Quote:
Originally Posted by greencactus3
a couple questions from a rookie team..

is it really BETTER to have them mounted on a non insulating surface?
is it better to have them mounted on a board that is easily deattachable from the robot?
is using velcro to mount each individual component a good idea?
is it not a good idea to mount them to our frame directly using velcro?(our frame is aluminum)
how easily accessible should they be?
is it a bad idea to need to flip the robot over to take out the battery?
has there been any accidents that you know of where any part excluding the motors and fuses had to be replaced completely due to any reason other than physical disturbances?
how what gets HOT? the motors..... the victors? well they already have fans on them...

well anyways, please tell us what is BAD. and what we need to worry about or what we need to be careful of or what has to be however (other than whats on the manual)

just don't want to do anything wrong! thanks!
Green Cactus,
You have a lot of good answers here, I am proud of all that responded. For us, we have used velcro in the past but were living with the experience of the bad speed controllers of the mid 1990's. For the past few years we have used perforated aluminum as a base, tywraps to hold things in place. We space parts out when we can to help with heat buildup (everything gets hot, motors most of all. Circuit breakers when they are continuously tripping too.) Parts should be accessible, if you get into the finals you won't have a lot of time to replace stuff so you want to be able to change it out quick. We have mounted our battery in a doored compartment under the robot for years. So you have to turn it over to change it, so what, you can't drop it on the RC accidently from there. If your wiring is insulated to begin with, you may not need to have the mounting surface insulated. Wood and lexan weigh a ton but a lot of teams use those materials for construction.
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