Comment by Greg Fletcher on December 31, 2012 at 7:10pm

Great idea. I did something similar a few years ago when I was working on my first auto drone (sky fun with an ardupilot, not mega the first one) after it started up full power on my work bench when I shut off my xmiter and it went to failsafe. That,s when I put in a ground speed safety enable. Now it is standard procedure in copter and plane.

What I did was put in an automotive type inline 30 amp fuse on the main line to the esc so I could disable the moter until ready for flight. I tapped of before the fuse though a 2 amp fuse for the avionics so I could run everything but the moter. Of course I had a seperate BEC for the AP and radio. I had a couple of bad take offs and stopped the prop when it had an unscheduled landing and every time the fuse blew before the over-current on the ESC shut off. Fuses are cheap, motors, ESC's and fingers are not. The fuse was mounted on the outside of the plane and was easy to find. I think this should be standard practice because crashes happen and you may forget to zero the throttle after you just crashed. Blown power fuse prevents fires after a crash. Small price to pay for a new fuse. Also protects from a shorted ESC or what ever. If you have ever shorted a battery accidentally and seen the wire insulation instantly vaporize you will install a power fuse, close to the battery.

3D Robotics Comment by Joshua Ott on December 31, 2012 at 11:06pm

Greg,

I like the idea of a fuse, but haven't been able to find a >100amp that wasn't too big and heavy. I guess my attopilot current shunt is my fuse.

Comment by Greg Fletcher on January 1, 2013 at 12:00am

Ya , I see how that could be a problem. I don't flu a mulicopter yet, but what happens in a crash in auto and its calling for thrust? I guess a good esc just handles any over current? Or you could just have a fuse for each motor. Maybe is a market for pdb with fuses?

Comment by Jason Wise on January 1, 2013 at 1:38am

for those outside the hobby, If this crashed with large lipos that looked like plastic explosives and the word kill on it.....Ill bet the cops will be called!

You could use a mosfet as your kill switch

3D Robotics Comment by Joshua Ott on January 1, 2013 at 1:39am

A fusible link is probably the best solution.

 I want to build myself a power management unit that will take care of a couple needs. The main battery balance leads will be plugged in first. A slow charge circuit will charge up the ESC capacitors with no spark and subsequent gold vaporization(!) when the main battery leads are then connected. Voltage and current measurement with stand alone alarms. Voltage regulator to feed flight controls, camera motion, and lighting. With the option of using a second battery to allow hot swaps of the main motor battery without requiring a reboot.

Comment by Jason Wise on January 1, 2013 at 1:48am

Here is a pic, you could tie it to a spare channel

Common use is antispark

http://tienda.stockrc.com/BTS555

I brought a few of ebay....I havent bothered as yet but once I go long range FPV Ill do something with them

3D Robotics Comment by Joshua Ott on January 1, 2013 at 1:54am

Jason,

I think it will make people feel better to know that they have an easy way to kill this robot. I do appreciate your comment though, maybe I need to add a little more information to the message, perhaps a label next to the plug describing what it powers, like "Motor". Then the word "Kill" would have some context. Maybe a lightning bolt style graphic?

The mosfet sounds interesting for sure, it would need to be bulletproof though, such a critical job keeping the whole craft in the air.

3D Robotics Comment by Joshua Ott on January 1, 2013 at 2:03am

Jason,

Thanks for the product link, I like that!

Comment by R. D. Starwalt on January 1, 2013 at 8:17am

Arming/disarming the power was one my initial concerns for my build.

HERE is my solution.

It would be easy enough to add Joshua's label or add an indicator so that other's could isolate power.

'KILL' might be misinterpreted. Perhaps 'Pull To Remove Power' would be less intimidating?

-=Doug

3D Robotics Comment by Joshua Ott on January 1, 2013 at 3:25pm

This is for a race car master power kill switch. I guess "off" is how you say kill in robot.

Interesting how provocative that word is, I'm sure the macro photo doesn't help, it's much smaller in real life.

Thanks for the feedback everyone, I'll make up another label version and see how that looks.

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