Axe/hammer question.

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Derek Dudge
Posts: 109
Joined: Thu Dec 07, 2017 9:32 pm

Axe/hammer question.

Post by Derek Dudge » Tue Feb 27, 2018 10:37 pm

In anticipation of planning a new robot I have a question I think I need to check up about. Caveat as always, this may be a daft question.

So I'm just about settled on an axe/hammer for project number 2. From previous threads and chats I know I'll probably be using a Vex ESC, I think I'll need this one https://www.rapidonline.com/vex-29-type ... er-70-6329 for gearmotors on the weapon alongside a nanotwo for the drive.

My question - connecting the weapon controller to the receiver when the receiver is built in on the nanotwo - Is this easy to do? I can't seem to find any posts here in any build diaries where this part is explained.

Cheers in advance!
My robots:

Third Law (antweight) - push/ram bot
Manticore (antweight) - hammer bot

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GeorgeR
Posts: 162
Joined: Sun Aug 28, 2016 9:53 pm
Location: Bath, Somerset

Re: Axe/hammer question.

Post by GeorgeR » Wed Feb 28, 2018 12:42 pm

Yep, that's the esc that most use for axes, and yes it's easy to hook it up to the NanoTwo using the nanotwos servo output pins.
The only potential issue with this way is that the servo output is wired to the Throttle channel, and an axe is better controlled using the Rudder stick, but this can be easily sorted by adjusting the Devo 7e settings. (not sure about other transmitters)

I'll make a longer reply with instructions when I get back from work.
Team Zero
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
Vampire - horizontal spinner - - Orion - horizontal spinner walker (coming soon)

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Rapidrory
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Re: Axe/hammer question.

Post by Rapidrory » Wed Feb 28, 2018 1:22 pm

With the NanoTwo V3s, the VEX can be powered directly from the servo socket without any additional wiring required.
Rory Mangles - Team Nuts

Robots: Nuts 2 and many more...

NanoTwo Motor Controllers: https://nutsandbots.co.uk/product/nanotwodualesc

Derek Dudge
Posts: 109
Joined: Thu Dec 07, 2017 9:32 pm

Re: Axe/hammer question.

Post by Derek Dudge » Wed Feb 28, 2018 3:29 pm

Ahh so it does go through the servo pins. Cool. I wondered if that would be it, or if it was going to be an under the heat shrink job.

It's going to be the v2 nano I'm using (too impatient to risk missing next batch of the 3s hehe) so I'd appreciate that extra info George, sounds like there's a little more to it wilh the older nanos? Although no rush! Whenever you get a bit of time. It's appreciated!

Oooh, and while I think about it, what ratio motors did you get for the weapon on your axe bot? I've already spotted the round fixture parts that go on the motor shafts and hold the weapon and am planning on getting a couple of those. Oh, and I have the same 7e controller :-)

Cheers guys
My robots:

Third Law (antweight) - push/ram bot
Manticore (antweight) - hammer bot

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GeorgeR
Posts: 162
Joined: Sun Aug 28, 2016 9:53 pm
Location: Bath, Somerset

Re: Axe/hammer question.

Post by GeorgeR » Wed Feb 28, 2018 9:53 pm

There's not much different with the v2 nanotwo, but the servo power pin outputs a regulated 5v rather than the full battery voltage, so you need to connect the Vex 29 power wire to the battery voltage.

When you get a Vex 29 you'll see it has 5 wires attached, red and black at one end (motor output connections), white, orange and black at the other (inputs). Connect the inputs as follows;
Orange (power) - Positive battery voltage wire
White (signal) - Servo pin nearest to centre of nanotwo
Black (ground) - Servo pin nearest edge of nanotwo, or negative battery voltage (they're the same thing)

Also worth adding you should remove the Vex 29 electronics from it's plastic case and wrap it in heatshrink/insulating tape, unless you like it being much larger/heavier than necessary.



To make the Devo 7e rudder stick output to the throttle channel;
Open the transmitter main menu (ENT)
Open "1. Model Menu"
Open "2. Mixer"
The Mixer is the bit of the deviation firmware that determines the relationship between what we input into the controls, and the signals that are sent to the receiver. Looks a bit like this;
(1-THR)(Simple)
(2-AIL)(Simple)
(3-ELE)(Simple) etc...
Select the (Simple) next to the throttle channel, and you will see a screen with a little graph on the right side.
Change the source "Src" from THR to RUD.
Select "Save"
Exit the menus, left/right on the left stick should now control the throttle output. Yay!


For Axiom I use two Pololu high power 50:1 motors, but unless you're an idiot like me and build a really big axe, one motor will be plenty.
Team Zero
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
Vampire - horizontal spinner - - Orion - horizontal spinner walker (coming soon)

Derek Dudge
Posts: 109
Joined: Thu Dec 07, 2017 9:32 pm

Re: Axe/hammer question.

Post by Derek Dudge » Thu Mar 01, 2018 2:54 am

Cheers George, that's an excellent guide. That's awesome.

Well I got some more polycarbonate ordered. Haven't bought motors yet but the plastic parts should keep me busy a while.

I'm not sure what's going on the end of the weapon yet. I'm keeping an eye out though.

Thanks again!
My robots:

Third Law (antweight) - push/ram bot
Manticore (antweight) - hammer bot

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GeorgeR
Posts: 162
Joined: Sun Aug 28, 2016 9:53 pm
Location: Bath, Somerset

Re: Axe/hammer question.

Post by GeorgeR » Thu Mar 01, 2018 10:23 am

No worries, it'll be good to see another axebot, there aren't many about.

For the axe head don't go too heavy, it makes the robot jump when you fire it, which reduces power and makes it a pain to drive. Axiom's is currently 28g which I've discovered is too much, I've turned down the power but it will still flip itself over if I fire it when turning or retract it too fast!
Team Zero
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
Vampire - horizontal spinner - - Orion - horizontal spinner walker (coming soon)

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