Power/failsafe LED

Lee, you know it worked when you tested it, but would you trust it to still be indicating correctly when your robot has been damaged in the arena?
If none of the lights were still on would you think it was then safe?
Can an event organiser be sure that the indicators are correct just because you say it works correctly?
Would you trust some one elses indicator system on their robot?, I would not, and by that logic I cannot trust yours either, just on your say so.

I am not saying that yours does not work, just that it is not possible for me to know that it, or any one elses indicator system is working correctly at all times.

When the link is in, that is the only warning that you need to tell you that the robot is dangerous.

The lights are fine for you to know that every thing is powered up, but when they are not lit does not indicate that they are not powered up, that is the crucial point.

You can never trust such a fragile thing like leds and bulbs common sence as to prevale and all bots must be treated the same with great care. All my lights do is tell me that all my systems are working at the start and to be honest i ignore them at the end and disable Gman the same way as normal. And personaly i think no one should trust any kind of indication that a bot is safe and us a bit of common sence

Sam, perhaps you could (without naming names) tell us more about that near miss incident? Maybe that would help this discussion a bit. As it is I am tending to side with Roger that as described the lamp system is likely to be unreliable, and most likely to fail UNsafe!

Perhaps a better idea would be to have an LED lamp connected to the two sides of the safety-link socket. When the link is in the pins of the led are shorted, and it goes out. If the link is out, then the full 12/24/36 volts is across the LED and it lights. (To survive high voltages it would benecessary to use a suitable LED, or LED and high-value resistor, or even an array of LEDs.)

This system would be a positive robot is safe indicator. All the failure modes I can think of (led fails / becomes disconnected, battery fails, battery short, wiring failure) would cause the LED to go out, which could be assumed to be a robot is dangerous or malfunctioning indication.

If a large LED was used with a mask perforated to say SAFE, then this would be a highly positive, and as far as I can see almost fool-proof system. No SAFE sign, the robot is a threat.

The only downside I can see is that the LED might, if left in for a great many hours, drain the battery. However, no roboteer should leave a battery in the robot for that length of time, surely?

You could perhaps combine this sytem with a link is in lamp as sugested. Multiple, parallel LEDs would be most reliable, but still not idiot-proof. An additional battery in lamp would provide extra warning, but again would be a danger in itself if it failed.

Richard, the batteries in WBC are left in all season, and are charged in situ, so an indicator across the link would mean that the battery would drain.
Removing the batteries from WBC is a considerable amount of work.
With the link removed they are isolated from the system so are safe, no need to remove them unless I need to work on it.

I have no problem with robots coming to my Yeovil show with whatever indicator system the builders like to put in them.
I shall regard any lights fitted to a robot as no more than decoration, the only safety criteria for me is, if the link is in it is dangerous, if out and the weapons locked with the gas turned off it is safe.
The lights may be used by the builder for whatever purpose they like, I shall pay no heed to them from the safety point of view.

Im sorry to sound a bit mean, but: That would be a down right stupid idea. A led will need 2-20 mA, this is enough to charge a capacity in a speed controler. This in turn could, in a freak occurence, trigger a valve that will set off a pneumatic wheapon.

Off is off... 0 current, slich, nothing. Otherwize it could potentially be dangerous.

Im not sure that system will work. In order for the LED to light the power components of the robot would have to be drawing power through it. If the speed controllers are inactive (e.g. no radio signal), they may not be attempting to draw any current from the main battery. The LED would only light up when the links were out and the speed controller was actively trying to draw some current, which is not very common.

I think.

Jim, that would not work for ours with 4QDs as there is a bypass bleed resistor that charges up the capacitors to allow enough power to activate the relays when the ignition switch is on. Its reason for being there is to prevent sparks when connecing the link. Its a bad idea forget it.

Roger, Use some common sense please. The power light is there because experiance have shown that robots in the past have removed thier link and have still been active (ie the link did nothing). IF and only IF the light is fitted correctly will you see that it is still on but it would alert people to the fact that it is still active in the pits. If I see a robot with any lights on it when its in the pits I would certianly treat it with caution would you? If you power up your robot and the light does not come on then whatever the reason (Light / link fault) it should not be allowed to fight. How many people to you expect to be at Yeovil. How many were thier last year :). Dont put people off going to your events as Im sure that many wont go if the FRA dont approve your event.

Common sense would indicate that if a robot has its link fitted incorrectly, so that removing the link does not remove power from the robot, it would fail technical inspection and not be allowed to fight. The inspection at the Worthing event included running the transmitter with the receiver on and the link out.
If damage in the fight could cause the robot to fail so that it is active with the link out, it could also cause the indicator light to fail.
Roger is correct about this, the only way to know a robot is safe is to have the link out, the gas off and the weapons locked (and even then be alert).

If a machine has a link removed and is still active due to poor workmanship or malfunction, then by the same rational a light that is off could indicate that a machine is still active.

Im not against the light idea - I just dont see it makes any difference. If a machine is in the pit then the radio and link must be in the tx control except for a tec check.
If a machine is in the arena I always assume it is potentially a killer, lights or no lights ill keep well away until its on a cradle with link out gas purged and locking pins visible.

Well, we€™ve got lights on both heavyweight, and feather weight.

Last night we were repairing and testing both robots....

The feather weight wouldn€™t work, the link was in... power light off, nice n easy for us to realise it was a battery connection that was the problem.

The light shouldn€™t be used as a guarantee, but....

After a fight when robots are immobilised, and a member of my crew has to go in to make them safe, a quick visual check, tells the person which ones are definitely live and which ones are ( visually ) dead. And so which ones to go for first.

At the end of the day it is another visual warning.

I fully support them in all weights.

Jonno
http://www.roamingrobots.co.ukwww.roamingrobots.co.uk
http://www.ukinnovations.co.ukwww.ukinnovations.co.uk