Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
component basics for beginner
Hi Guys
Ok Just trying to get my head around the basics to make a fighting robot
Ok got a Spektrum dx5e transmitter(are these ok?)
I need -
- br6000 receiver
-a speed controller like the ibc -its like the motherboard that connects everything right?
-two drill motors( Cant find the 12volt type of gmc at bunt, only the 14volt- will this be ok on a 12volt battery)?
-weapon motor
-weapon
-12volt battery
-wheels
-chassis
-all the correct plugs to join everything together
-kill switch for the robot
Speed controllers: I like the Sabertooth 25x2. Some people aren't a fan as it will current limit on bigger motors but I have 2 and never had any trouble. (its out of stock atm so don't expect to get it quickly)
Also you will need a 12V powersupply to run the charger. I use a 20A 13.8V one I got from electus/jaycar
Battery: Get A123s. Seriously a 5 cell pack @ $9 a cell from lightninngEV bit of a pain to make it but really worth it.
Drives & Motor: Drills + Bunnings red wheels I reckon to start out with. Still working fine for me. The voltage on the drills isnt critical. The will still work @ any voltage just the power you get at a lower voltage than specified is lower. (P = V^2/R) So 1/2 voltage 1/4 power 2x voltage 4x power in theory. 12V drill motors at 18V+ sorta fry most of the time.
(It may be worth looking at the gearboxes from bytrapper. $67 is not really that much more expensive than the drills in the long run.)
The rest well you can prolly research and work out yourself. If you want to compete against NSW spinners minimum is prolly 6mm steel shell. But we are a bit nicer in QLD. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Thu Jun 10, 2010 6:36 pm
Dylon
Joined: 09 Nov 2006
Posts: 631
Location: Newcastle, NSW
Joined: 09 Jan 2009
Posts: 518
Location: Wantirna, Melbourne
charger: turnigy accucel-8, it has 3 times as much power as the accucel6 for not much extra pricewise. get it from hobbycity.com
powersupply for charger: get a 12v/29A one from eBay, many ppl here use them and it will last you for many many years _________________ http://au.youtube.com/user/crustydemonsully
The day I stop giving 100%, is the day I stop competing
Fri Jun 11, 2010 12:59 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Thanks or the feedback guys....ok need the charger on my list . Wow 6mm steel for armour, those weapons must really pack some punch!
thanks
M&J
Fri Jun 11, 2010 9:22 am
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
You could use thinner steel, but it won't last as long. With the charger, check what the total power rating is - the higher the better as you want to charge your batteries as fast as they will allow. A 150 watt charger would be the starting point IMHO; chargers are worth investing in as they can be used for other projects or even charging your car battery.
If you don't fancy making your own battery packs, look at lithium polymer (Lipo) packs. They are not nearly as dangerous as peopl mak out as long as you use a bit of common sense and they can be cheaper than A123 batteries.
Fri Jun 11, 2010 12:05 pm
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Hi Guys thanks for the info!
So do many robot builders use one sabertooth controller for steering, and just have a switch controlled by a servo for a weapon? I guess you would need a really reliable switch mechanism on that servo(which was just on or off.) That would be ok for a spinner wouldnt it?
thanks
Miles.
Sun Jun 13, 2010 11:22 am
andrew
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
that is one way of doing it with a servo hitting a microswitch which triggers a large enough current relay wired into the weopon system
If your using a sabretooth you may as well get a battleswitch also
Or if u know how much current the weopon motor system draws some form of speed controller will also work _________________ Andrew Welch, Team Unconventional Robotics
Sun Jun 13, 2010 11:31 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Cool those products look like a cheaper alternative to a second controller and way better than a servo switch. Thanks Miles
Sun Jun 13, 2010 11:46 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
One more question..... with the batteries. How long do they last? Do you need to charge them in between matches or does one charge last all day or do you need to have more than one set of batteries for each robot?
Most people use A123 batteries. These will last about 5-10min in most robots depending on how much power they use. You will need to charge them in between fights. An extra set is handy but not 100% essential.
There is a lot of variation and factors you must account for this is just an example.
Last edited by marto on Wed Jun 30, 2010 9:40 pm; edited 1 time in total
Wed Jun 30, 2010 9:39 pm
seanet1310
Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide
A123's and nicads need a charge between matches.
A large enough lipol could last all day but not many people run them in aus and would have to be quite large to last a big event. _________________ Remember to trust me, I am an Engineer.
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
generally you size the batteries to just last one fight so your not wasting weight on unneccesary battery power.
a few years ago you needed alot of batteries. but the chemistries like A123 cells can be charged so fast i generally just use one pack all day and charge it really fast. but its always good to bring spares in case you dont have time to charge , like in the final rounds of some events. so i bring 3 packs all up.
lipoly batteries though you'll need plenty of spares because the majority take at least an hour to charge. there are new ones out though that are faster but still nothing alike the a123 cells.
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Hi Guys
Ok Got a drill motor ready (and I'm following the awesome "drill hacking101" guide) And Im up to the bit where you put the screws down into the plastic gearbox to lock it up .
Do they need to be 5mm metric i've got a bucket full of 3/16ths size imperial bolts (philips head tops) Will these work? Is there a another reason for the set cap screws? Also do these bolts need to stop the bit that spins underneath?
thanks
Miles
Sat Jul 03, 2010 7:02 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
The screws don't absolutely have to be 5mm, but that size fits the holes in the drills very well without having to cut threads. 3/16 is 4.7625 mm and that will probably be too loose to stop them working loose. The reason for using grub screws rather than regular screws is two-fold: the heads on many screws prevent them going into the holes straight as they interfere with the plastic around the end bearing. The more important reason to use grub screws is that they don't stick out from the drill body and interfere with any motor supports you put around the end bearing.
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