so if you get a hit from a spinner and your arse is opened up and your wiggling around on one wheel ..with a $300 speed controller sitting exposed you can stand there and say "hey if you cant take dont get in the arena " yeah right !!!! a reality check please
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that's why I don't use a $300 speed controller

no offence, but I reckon the IBC is way too expensive to use for this kind of thing, as are all the high end radio sets.

On the weekend I did notice heaps and heaps of radio issues, and IBCs going mental.
My tested-for-5-minutes-after-throwing-it-together microswitch controller made use of a $30 complete radio set, and controlled drive and weapon power semi individually from two channels using a sort of crude mechanical multiplexing.

It also worked flawlessly until the receiver got unplugged by a flying battery pack
When I got home and plugged it back in everything still worked!
I was also amused to find that plan-B's spinner cut through the 3mm armour 25mm in front of the control board, and the blade had actually passed between two of the microswitches. No contact, but 10mm up or down and there would have been some major switch shattering!

Everything I put in that robot I was prepared to lose in a shower of robotic flying shards - and that's the only way I could do it. Anything you're worried about losing in only limiting the possibilities of the competition.

Hopefully some people enjoyed it when I asked plan-B to keep having a go even when my bot was sitting against the wall with the wheels in the air, the saw stalled, and no control
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The Engine Whisperer - fixer of things

are yes but did your robot have a fail safe or the control a ibc allows?
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Team KO

@Chris, If i did see anything vital in harms way i would forfit teh match and congratulate the driver of that spinner for winning the match. I am not an ideot here. If ahnialation takes out the rear and the reciever is dangling ill scream forfoit so it doesnt get mangled.
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Andrew Welch, Team Unconventional Robotics

quote:

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Originally posted by Timothy Forde:
are yes but did your robot have a fail safe or the control a ibc allows?

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DumHed,
What you have just explained about your radio control configuration

quote:

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My receiver does shut down the servos if there's no input signal, but obviously it won't turn off the main power if the power switches are jammed in the on position and there's no radio.

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Good points there ajax but u dont need an IBC to be in safety rules. A mere failsafind device from technobots or something wil do or just plain common sense. Like checking the swtches arent triggered before power is on.

Im just saying though that u dont need an IBC to have a cheap and good drive system.
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Andrew Welch, Team Unconventional Robotics

quote:

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Originally posted by andrew:
Good points there ajax but u dont need an IBC to be in safety rules. A mere failsafind device from technobots or something wil do or just plain common sense. Like checking the swtches arent triggered before power is on.

Im just saying though that u dont need an IBC to have a cheap and good drive system.

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I've never seen a radio set that can return the servos to middle if there's no control signal.
The center postion is controlled by the pulse width coming from the transmitter, so with no signal there's no reference point.
Most radios are like this, but at least the one I used shuts down the servos when there's no signal, so even if the bot is powered up it won't do anything random.

I was looking at doing more of a fail safe setup, but it would mean building a circuit to watch the incoming pulse train inside the receiver and controlling a main switch from that.
Not super difficult, but a bit more than could be done in the time I had.

If I had a high powered spinner or similar weapon I would have added more safety, but being a last minute job that wasn't possible, and in the end it didn't do anything remotely dangerous.

What I will be doing soon though is building a controller that can directly decode the pulse train from the receiver chip, before it gets split into individual channels. That will suddenly make my 2 channel receiver into a 9 channel intelligent controller with mixing and fail safe.
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The Engine Whisperer - fixer of things

Robot Marketplace has just the thing for you - http://www.robotcombat.com/store_rc_accessories.html The micro failsafe would work for all servo controlled bots.

Perhaps we should look at making such a unit mandatory for servo controlled weapons?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

those look ok, but realistically there are always going to be times when a failsafe is not fail safe.

If your receiver power is cut (as it was in mine) then that particular unit will be of no use at all, since it still needs power to return the servos to the brake point.

If power is gone it won't do anything, and if a servo or servo horn is damaged you can still end up with weapon power being on even if the receiver and fail safe are working.

The only way I can see it working properly is to monitor the receiver outputs, and hold a relay energised as long as the servo pulses are all within spec.
That way if you do end up with major mechanical damage the relay will either drop out due to lack of power, or you can turn off the transmitter to cut power completely.

Of course you can still end up with power being maintained if the relay welds itself on (easy to happen with stalled high current motors), or wiring get shorted out.

This can happen even with an IBC or similar. If you cook the FETs and they go short, or you cop a hit that shorts the motor power on you won't have any way to stop it.

Personally my view is that with 12kg bots the fail safe is not that important, since it isn't possible to cater for all conditions anyway, and the power available isn't that great - so there's not really a huge danger present.

I'd be inclined to stick with the cutoff switch / removable link on the main power - and then focus more on having a way to disable errant bots physically.
If a bot is running around the arena flat out with the weapon running the best way to stop it would be to throw a large blanket over it, and to have a bit of 4x2" timber or something to push it around if necessary.

Really it's a bit stupid to rely on an electronic failsafe when it can only prevent problems caused by a complete loss of transmitter signal.

Next time I'll have my own multi channel electronic controller anyway, which will pass the usual requirements - and will cost a similar amount to one of those fail safe units.
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The Engine Whisperer - fixer of things

quote:

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Originally posted by DumHed:
I've never seen a radio set that can return the servos to middle if there's no control signal.

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if the power is cut to the receiver though it can't re-center the servo so it's pointless as a fail safe.

There's also no way I'd put a $200 receiver on something that's designed purely to get smashed up

That said, I wouldn't even put a $200 receiver on any other radio control device, but I'm a cheapass when it comes to things I don't consider to be necessary
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The Engine Whisperer - fixer of things

btw the disk on Plan-B was "almost" fail safe, I had it wired up with the wrong fet, simple fix.
btw if anybody else wants a "circuit diagram" for a fet controller like that lemme know (total cost is around $4 or $5 i think from jaycar and it was made with a grinder to cut the tracks and a drill for the holes.)

also I will make a "servo safer" simple little circuit total cost < $20 that should do multiplle servo chanells returning to a set position on loss of signal and could do battery elimination for the reciever battery too. (and if i get really funky mixing too)

have you servo switchers considered using something like a gamepad rather than joystick style radios? it would be easier to controll wouldnt it?
most stick radios would be fairly easy to mod to allow gamepad controll (as an option you could switch on and off)

I think the controls work ok with the stick, it just depends on how the switches are set up for minimal delay waiting for the servos to activate them.
Servo switching is certainly not ideal, but it is a very simple and effective way to switch a lot of current from normal radio gear.

I'd be interested in having a look at your FET setup if you don't mind emailing me the info. I'll PM you my email address.
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The Engine Whisperer - fixer of things