How-To: Anti-Spark XT-90 Loop Key

[sl33py]

It's not a marvel of engineering. It doesn't light-up blue. It's not as nice as the push-button anti-spark.
It's also not $60.

This might be a bit remedial for some of you (you know who you are), but i wanted to show how i built one in case someone else wants to make their own. You can do it easier/simpler, but i had some time to fiddle in the garage and enjoyed making it for my next build.

Starting off with the anti-spark XT-90:

I took some 12/2 wire i had laying around and the copper ground wire works perfectly to bridge the contacts for the loop.

I like modular. If it ever fails or i want to do something differently i can easily swap it out without cutting it out.
6mm connectors:

The slot is so i can squeeze it to better fit/solder.

Mocked up:

Finished with some heatshrink and paracord so i can easily pull to disconnect.

Finished:

Only issue i can imagine is depth to fit. I will likely turn it flat and secure the bottom down. I might also attach a small cord/wire to the paracord loop to prevent it from getting lost.

Nothing too special, but i think it turned out well. I plan to install on my new e-Omen (ongoing slowly).

Hope it helps!

 

[torqueboards]

Perfect tutorial!

Now I can refer everyone to this page whom don't know what a XT90 Loop Key is

 

[whereswally606]

I like this a lot, I would say the straight through (I.e) using more 6mm connectors is unnecessary more an aesthetic thing but the loop part is great.

 

[camyboy]

I got some 4mm HXT connectors instead of the 6mm. Would it work the same?

 

[vince086]

I got some 4mm HXT connectors instead of the 6mm. Would it work the same?

Not really.
The XT90 connectors used for this have a resistor built in (under the green bit). That resistor prevents the spark.

 

[Simonvtr]

I order some xt90s to prevent sparks when I attach my battery to my controller.
I thought it was straight forward soldering like it would normally with a plug?
May you explain to me what is the purpose of the loop key?

Thanks
Simon

 

[camyboy]

I got some 4mm HXT connectors instead of the 6mm. Would it work the same?

Not really.
The XT90 connectors used for this have a resistor built in (under the green bit). That resistor prevents the spark.

no no I bought the XT90 anti spark, But Im talking about these

to make these

. Instead can i just use 4mm connectors. instead of the 6mm

 

[torqueboards]

You don't need to use the 5.5mm bullet connectors. You can also just solder 10awg wire directly into the connector.

 

[camyboy]

You don't need to use the 5.5mm bullet connectors. You can also just solder 10awg wire directly into the connector.

Oh okay, sounds good

 

[sl33py]

You don't need to use the 5.5mm bullet connectors. You can also just solder 10awg wire directly into the connector.

Correct! I mentioned i like modular:

I like modular. If it ever fails or i want to do something differently i can easily swap it out without cutting it out.
6mm connectors:

The slot is so i can squeeze it to better fit/solder.

So i guess i wasn't totally clear. You can easily wire this in by just soldering directly to the bottom XT-90. I set mine up to be modular so i can swap it or bypass it with just a simple plug/unplug. I made it more complicated than necessary, but wanted that feature so i can swap to another board later, or remove it entirely.

 

[camyboy]

So im still lost. This is how im assuming i would connect it all together.

Im just lost. There are 2 input (red n black) from batteries that need to reach the ESC but only 1 input and 1 out for the anti spark loop connector. Do i plug the red wire from battery to the black from ESC? or black from battery to red on ESC?

 

[torqueboards]

This is the direction. The only thing that the loop key does is break the full circle connection.

So when the loop key is removed - your system is off.

When plugged in - you allow the current to flow to your ESC to your motors.

Everything else is just different connectors with different amp ratings to make it happen.

Of course, use less wire and less connectors to prevent more wire bulk in your setup.

 

[sl33py]

nice simplified drawings. Torque has you squared away.

the loop key is merely an in-line interrupt on one of the wires. Positive or negative. When removed it disconnects power like a breaker in the open position. When connected it allows that wire to complete the circuit (the anti-spark plug also suppresses the spark when connecting). Simple.

 

[camyboy]

nice simplified drawings. Torque has you squared away.

the loop key is merely an in-line interrupt on one of the wires. Positive or negative. When removed it disconnects power like a breaker in the open position. When connected it allows that wire to complete the circuit (the anti-spark plug also suppresses the spark when connecting). Simple.

This is only copper wire i have? i just stripped the silicon http://imgur.com/TbWLSej would it work?

 

[torqueboards]

That works. You just need conductive wire. You could even just use 10awg wire.

Of course, you should tin/solder around the loop key to strengthen it.

 

[camyboy]

That works. You just need conductive wire. You could even just use 10awg wire.

Of course, you should tin/solder around the loop key to strengthen it.

I tried before like u told me and http://imgur.com/rngfZTT. The cable is too thick. just gonna heat up the end to remove the cable and try the copper

 

[camyboy]

That works. You just need conductive wire. You could even just use 10awg wire.

Of course, you should tin/solder around the loop key to strengthen it.

Hows mine http://imgur.com/JEIUonv

 

[sl33py]

That works. You just need conductive wire. You could even just use 10awg wire.

Of course, you should tin/solder around the loop key to strengthen it.

Hows mine http://imgur.com/JEIUonv

Looks good! Make sure to insulate it so no exposed wire.

 

[camyboy]

That works. You just need conductive wire. You could even just use 10awg wire.

Of course, you should tin/solder around the loop key to strengthen it.

Hows mine http://imgur.com/JEIUonv

Looks good! Make sure to insulate it so no exposed wire.

How do I do that if I already soldered it on

 

[torqueboards]

Your suppose to put the heat shrink to the side and finish off the soldering on the last end.

You should be fine though since that single plug doesn't cross polarity. You can just heatshrink the entire connector. And/or wrap with electrical tape and then heatshrink the connector.

 

[sl33py]

Your suppose to put the heat shrink to the side and finish off the soldering on the last end.

You should be fine though since that single plug doesn't cross polarity. You can just heatshrink the entire connector. And/or wrap with electrical tape and then heatshrink the connector.

Agreed. I'd wrap a simple loop of electrical tape around the top of your loop to insulate it, then use any short length of string to pull on to disconnect. Heatshrink the whole thing and poke your string through, or you can simply pull on the plug/loop. I like the string option obviously. I also used a bright cord w/ reflective bits in case it gets dropped it's easy to spot w/ a bright light (headlamp, flashlight, etc.).

I'm just not a fan of exposed wire. Think if it got wet (not sure where you are placing it). Worst case i don't want to short if i can avoid it!

 

[camyboy]

Your suppose to put the heat shrink to the side and finish off the soldering on the last end.

You should be fine though since that single plug doesn't cross polarity. You can just heatshrink the entire connector. And/or wrap with electrical tape and then heatshrink the connector.

Agreed. I'd wrap a simple loop of electrical tape around the top of your loop to insulate it, then use any short length of string to pull on to disconnect. Heatshrink the whole thing and poke your string through, or you can simply pull on the plug/loop. I like the string option obviously. I also used a bright cord w/ reflective bits in case it gets dropped it's easy to spot w/ a bright light (headlamp, flashlight, etc.).

I'm just not a fan of exposed wire. Think if it got wet (not sure where you are placing it). Worst case i don't want to short if i can avoid it!

Hows this? I can wrap some electrical tape too if needed http://imgur.com/a/cwo4I

 

[sl33py]

Looks good to me!

I would heat shrink it to seal it up as well, but that's overkill. Yours is fine as is.

 

[camyboy]

Looks good to me!

I would heat shrink it to seal it up as well, but that's overkill. Yours is fine as is.

Sweet thanks, I just wrapped some electrical tape. So this is my wiring set up, http://prntscr.com/8wxelw
For the XT90 I dont think It matters which +/- connects to but positive from battery is going in positive and exiting negative which enters the postive ESC,
The circle means I am going to replace that connector the the opposite. I believe its female connector.
The two X's near the XT90 means Im just going to remove them and soder them to the XT90 connector it self

Just scared to connect everything because I did before this and spark came out from the red series connector and burnt the connector. And of course I dont want to fry anything because this is 750$ from a minimum wage high school student is a lot.

Thanks for the help, really do appreciate it

 

[sl33py]

You need to make sure your batteries are connected correctly in series. The middle + and - should pair up and you should have one red positive and one black negative go to your esc.

Don't connect until that's clear!