First time build! Devils Advocate! Noob questions aswell!

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gdibz
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First time build! Devils Advocate! Noob questions aswell!

Post by gdibz »

So i've decided to make my own ant weight robot, i've bought all of the parts (i hope) buying parts as i go along aswell! and im hoping that I can get advice along the way! lets get to it then here is my part list:

Chassis - Im beginning with polycarbonate to build a prottotype before going on to an aluminium

ESC - Turnigy 20A Speed controller x2 (mistake meant to buy 10A but oh well)

Voltage Reg - simple 5v reg for reciever (problem when first building explained later)

Battery - Turnigy Nano-tech 2s 7.4v x2(one for speed controllers and one for reciever

Servo - EMAX ESO8MA

Reciever - RadioLink R7EH 2.4GHS 7CH

Transmitter - T6EHP(Need a bit of help explained further along)

Motor - Micro metal gearmotor (extended shaft) (50:1) (pimoroni(dot)com)

Wheels - Pololu Wheel 32x7MM

(PLEASE NO COMMENT ON BUYING KITS AND IF ANY SUGGESTIONS ON A PART LET ME KNOW IM OPEN TO BUYING A DIFFERENT PART (WITHIN REASON OF PRICE THOUGH))

So I began my first mistake casually playing GTA 5 and trying to connect parts together not paying attention (not good combination) and long story short sparks flying from cable and a blown up capacitor in the reciever i believe, i had connected a battery to speed controller along the wire I tried to connect reciever (poof and a line of smoke) forgot to put VR before the reciever so a new reciever was bought I have now decided to use 2x battery one for the reciever easier to setup and one for speed controllers.


Some questions hopefully someone can shed some light on:
Speed controller to allow robot to go forward and revers instead of the current break any suggestions??
I can connect my servo directly to the reciever and control it but i cant seem to connect my motor and get it working got it workign once?
How do you setup mycontroller to controll left stick to move forward right stick to steer?

btw im looking for a switch which requires a small screw to conenct the wire to another wire (hopefully someone will understand what i mean.....)

Sorry if anyone is annoyed at my build please feel free to suggest some improvements......
EpicentrE
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Re: First time build! Devils Advocate! Noob questions aswell

Post by EpicentrE »

I'll just copy and paste my reply from the FRA forums here, as it's still all relevant;

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I'm not sure where to start with this...

"ESC - Turnigy 20a" As far as I'm aware Turnigy don't make a reversible ESC for brushed motors. If you bought one for use with brushless motors, it won't work with those drive motors, as they're brushed. If you bought one that doesn't say it has reverse, or is bi-directional, then it will only go in one direction. Can you link what you bought please?

Voltage Reg - This is not usually required as a separate component. Usually your ESCs will have a built-in voltage regulator (also known as a BEC) to power the receiver and servos, or you can just buy a receiver and servos that will work up to full voltage anyway.

Servo - This servo is a little small. It'll work, but it'll be a bit weedy. I would recommend one of these: http://www.hobbyking.com/hobbyking/stor ... duct=24764

Your writeup at the bottom is very worrying. Lipo batteries can very easily go up in smoke and/or fire if not used properly, and you're lucky that you only damaged your receiver and not, say, your face or your house. Please be more careful.

You don't need two separate batteries. As I described earlier, there are multiple ways to lower the voltage for other components, or even just to get components which don't need the voltage lowered in the first place. The servo I linked above will work without regulation.

My main concern though is that everything I've just written is fairly easily found with some research. You've obviously done a bit since you've bought some good motors and wheels and know roughly what components you need, but it feels like you've just thrown money at the rest of the components without any idea of what you're actually looking for, and you've endangered yourself in doing so. Please do some more research and ask some more questions before progressing any further. Post a full parts list and have it verified that you're not doing anything obviously wrong (as you have done above) before randomly plugging things in to one another.

Best of luck.

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To answer your new questions that weren't in the original post;

If you're dead set on not wanting a kit, RapidRory still sells his speed controller boards separately as far as I know, which is going to be your best option. Failing that, Fingertech TinyESCs, but they're expensive.
You can't connect a motor directly to a receiver; you connect it to the speed controller, and then connect the speed controller to the receiver. As I mentioned above if you bought the wrong type of speed controllers this won't work.
I'm not familiar with your transmitter, but it should be a case of working out which channels are on which axis of which stick and then connecting your speed controllers to the relevant channels on your receiver (unless your controller doesn't have mixing, in which case it gets more complicated).
Fingertech sell a mini power switch which sounds like what you've described.

I'd also advise taking a look through this thread: http://robotwars101.org/forum/viewtopic.php?f=10&t=1399 as it will hopefully give you a better idea of how to wire everything up. It's a bit out of date, but the principles are mostly the same.
Scott Fyfe-Jamieson, Captain of Epic Robotics. Champion of AWS38/41/42.
http://www.epicrobotics.co.uk
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Shakey
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Re: First time build! Devils Advocate! Noob questions aswell

Post by Shakey »

Chassis - I'd just stick to 1.5mm polycarbonate. I've found it takes hits better than aluminium.

Battery - You only need one battery just split it off to go to the ESC and VReg, 180mah 2S should do.

ESC - As you've found they don't reverse. A N2LVLP esc from rory (RapidRory on this forum) is pretty much optimal and (the non kit version) should plug into your Receiver. It has a V-reg for the receiver built in so you only need to connect a battery to the ESC. 2 batteries won't stop your receiver smoking like it did.

Radio stuff - Not the standard choices but should work.

Wheels/Motors/Servo - All seem pretty good to me! As Epicentre says the servo isn't very powerful, I've used it in grabbers before but wouldn't recommend for a flipper.

Connecting a motor to the receiver might be why it is an ex-receiver. Servos have their own speed controllers built in, receivers do not.

"How do you setup my controller to control left stick to move forward right stick to steer?" that would be called mixing, some transmitters can do it themselves, some speed controllers do it themselves (Like the N2LVLP) or you can buy a v-tail mixer to do it.

I hope that helps you out. :)

EDIT: Was typing as Epicentre posted.
Nuts And Bots - For all your components and ready built antweights!

Alex Shakespeare - Team Shakey / Nuts And Bots / Team Nuts:
AWS 44, 45, 49, 51 & 55 Winner - Far too many robots!
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joey_picus
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Re: First time build! Devils Advocate! Noob questions aswell

Post by joey_picus »

Turnigy brushed 20a controllers *do* exist, but are meant for model planes so obviously will have no reverse function, which while not necessarily essential for a combat robot - ...Chickens From Outer Space! won a couple of fights despite having no reverse - it obviously helps a lot! For controllers that work and have been extensively battle tested, I can vouch for Rory's electronics, and people have also used the Fingertech tinyESCs and BotBitz 10a controllers (also available in the UK) with success, although both of these are single-channel rather than dual-channel like Rory's boards. It's also very possible to hack servo boards and use them as cheap single-channel speed controllers, although you may want to take the boards out of non-micro servos!

I'd be concerned too about using a two battery system and a regulator - aside from the obvious implications for the 150g weight limit and (as Scott pointed out) safety, it's just not necessary and might even be causing some of your problems, all the above options (except possibly the servo boards) will have regulators built in so you could be overloading the reciever.

(N. B. I don't dispute what Alex said regarding polycarbonate, but I have had serious issues in the past with polycarbonate chassis cracking along stress lines and folds, so - as they say - your mileage may vary. You'll find an approach that works for you though - unlike the electrical side, antweight mechanics generally won't set you on fire!)
Joey McConnell-Farber - Team Picus Telerobotics - http://picus.org.uk/ - @joey_picus
"These dreams go on when I close my eyes...every second of the night, I live another life"
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