Power/failsafe LED

That sounds a lot more clear, but I dont entirely agree about receiver power. If the link complies with the rules, it removes all power to the weapons and drive systems (systems that could cause potential human bodily injury). Receivers and a few microprocessors cannot cause any injury on their own.

Granted, the logic circuits must run off a battery and this could conceivably become connected to the drive side by severe damage. In my case I dont see this as a risk because I only use PP3 batteries, which are too puny to turn a motor. In the general case, I think the risk of this happening is of an order of magnitude lower than the link connector becoming shorted by damage.

The other case is that the logic battery becomes connected to the drive or weapon systems by bad design or workmanship in the first place; I also think this is much smaller than the risk that the link wasnt properly wired. Im open to debate about this, though.

Another case you may bring up is that the receiver circuit could activate a solenoid or IC engine throttle. Here, the compressed gas activation valve or IC kill switch just take the place of the removable link, so the situation is analogous to that of electrical system.

Now I have a new (possibly stupid) idea....(not just to keep this thread alive and on topic)

We are all talking about LED:s lighting when robot is unsafe. What about the opposite?
A LED and a zener in series, connected in parallell with the link. Zener voltage equals battery voltage -3V (or 2V or 4V or something).
What would this mean?
Link out: LED lit (assuming battery voltage is not too far down)
Link in, independant of battery and connector status: LED off
Any connection to LED broken: LED off
Zener broken: LED off, or if zener shortens, LED burns out quickly = LED off.

As you can see, this might not always show safe, but if it does, it means safe....

You dont need a zener, just a resistor.
Besides that, this construction is dagerous. The 20mA flowing thru the led would be plenty to charge the capacitors in the speedcontrollers. They would store enought energy to trigger a valve or something.

Nope....with a resistor it will, yes, but with a correctly matched zener, it will only charge those capacitors to a maximum of 2-3V, which should not be enough to do anything serious....afaik...

Once the capacitors reach 3V wont the LED go out? If currents flowing through the LED, it has to go somewhere...

Depends on how the speedos look (electrically, that is). If it is 100% capacitive (which I don´t think it is) the LED would go out.

So....is this silence to be interpreted as good idea or too stupid to be commented?

Probably neither Jonas...more likely folk are just bored with how long this thread about a simple LED has gone on, everything has just about been argued to death.

Tom

It may be simple to implement in your situation, but bear in mind that there are an infinite number of robots that are valid within the current rules. Saying this is simple without any qualifying comment gets us nowhere.

Thanks for reading before you post...:P