Team Coolspeedbot: first feather weight robot

[RogueTwoRobots]

You can't put the LED in the link itself, as the link generally only completes the circuit on the positive wire, whereas the LED needs a positive and negative connection. Unless of course you run a double pole link that breaks both positive and negative lines, but that's extremely uncommon.

As far as I know, using the LED on a controller such as a Sabretooth is also not permitted. If the Sabretooth loses power or the LED breaks in battle, there's no indication to show that it's on, but the robot could still be fully armed. That said, the same could happen with a standalone LED, but it's easier to mount them where they're clearly visible. A Sabretooth's LED may not be bright enough to be visible either, unless it's mounted close to or nearby a see-through panel, which puts it at risk of receiving battle damage. And it's much cheaper to replace an LED than a pricey speed controller.

[R9000]

didn't nobody notice during the tech check at extreme robots?

There wasn't really anyone doing tech checks for the featherweights, at least not thorough ones. David looked over mine quickly, hence why I added the locking bar for the Sunday. He must not have seen where the LED was connected, after all you can't notice everything. Anyway, it was never a problem. I'll fix it for next time.

[Theo]

What about the light on a sabretooth board? it turns off when there's no power and ready to run out the box. Alternatively, you could put the LED in the removable link, I would be interesting and easy to check if it's in or not.

[Coolspeedbot]

Ah, I didn't know that. My bad.

didn't nobody notice during the tech check at extreme robots?

[R9000]

Yep, needs to come straight off the main battery supply after the link and not through any circuitry.

Ah, I didn't know that. My bad.

[Coolspeedbot]

Yep, needs to come straight off the main battery supply after the link and not through any circuitry.

One option is to run a few LEDs in series to drop the voltage. In Coyote, I used off the shelf 12V LEDs but was running the robot on 6S/22.2V. Wired up in series, they each see 11.1V which is plenty to illuminate them. Saves faffing about with resistors and such.

Ok, I think I understand how that works, but i'll try the resister first.

[RogueTwoRobots]

Yep, needs to come straight off the main battery supply after the link and not through any circuitry.

One option is to run a few LEDs in series to drop the voltage. In Coyote, I used off the shelf 12V LEDs but was running the robot on 6S/22.2V. Wired up in series, they each see 11.1V which is plenty to illuminate them. Saves faffing about with resistors and such.

[Coolspeedbot]

Personally I'd run it off your 5V BEC. You'd only need something like a 100 Ohm res for that.

I thought you couldn't do that cause if the ESC messes up and the BEC stops working, the light will stop lighting. it had to be getting it's power from the battery but not through any of the electronics like ESCs and receiver.

[R9000]

Personally I'd run it off your 5V BEC. You'd only need something like a 100 Ohm res for that.

[Coolspeedbot]

Looks like I need a 680 ohm resistor for a LED to run on a 4cell Lipo. Or 330 Ohm for 2 in parallel.

[Coolspeedbot]

thanks Nick I'll give that calculator a look

[overkill]

I guess you are going to use an LED? They all work on about 3V and will definitely need a dropping resistor. Some LEDs come in a mount with a resistor and you might be able to find one that matches your battery voltage - you really can't over-volt LEDs and expect them to last, so don't be tempted by something that's close.

Finding the resistor value is dead easy; just google 'LED resistor calculator' and pick one of the many choices. You will need a couple of details from the LED spec sheet and then the calculator will show you exactly what to buy.

[Coolspeedbot]

So I said I was done with the electronics, but I still need to fit a power light. I've fitted a plug ready to connect the light but I would like to double check what light I should get. whats the minimum voltage I should get? if I need resisters what should I get it?

[Coolspeedbot]

So it looks like I'm 'done' with CAD in regards to the hardox stuff. I just need to save up a few hundred pounds for it (he says not knowing the approx. cost).

[overkill]

Its not a big deal unless you are using soft material or really crappy screws