new robot

[Guest]

Re: new robot

just found out having a buget cut

i was thinking of having a r/c car and puting a armor shell over it like demolisher in this vid

http://www.youtube.com/watch?v=JdYl7Bi7 ... re=related

[Guest]

Re: new robot

to make a fw

[joey_picus]

Re: new robot

I think this has been discussed before (if you were to look through the forum archives): viewtopic.php?f=111&t=261

To save you reading that, if you want your featherweight to survive in any form it's a monumentally bad idea if you're having your budget cut I strongly reccommend you go down the antweight route instead.

[RogueTwoRobots]

Re: new robot

Hehe, in that Trials video I love the fact Shunt's got the finishing flag attached to his axe - that's amazing

[Guest]

Re: new robot

lol

[muchalucha]

Re: new robot

You can still build a FW on a very small budget . As esc's go , if you arereally ona budget i could build a on of backward forward esc , there not great for fine control but they will get your robot moving and there very very cheap. (around 30 quid)

[daliad100]

Re: new robot

Are you thinking microswitches, servos and relays?

[muchalucha]

Re: new robot

nope , servo inards , darlington arrays and relays , im loking at replacing the servo innards with a PIC miconcontroller but i need to get a programmer first :P

[daliad100]

Re: new robot

Much cooler than microswitches

This might be of interest and/or use to you: http://trebor69.tripod.com/speedcnt.html
Although there's no backwards, it does have variable speed.

I've also been looking at trying to use servo innards to drive an H-Bridge for full Forwards/Backwards variable speed. I have a few ideas but I'd really need to get some servos and an oscilloscope/data logger to figure out what will and won't work.

[widow_twanky]

Re: new robot

nope , servo inards , darlington arrays and relays , im loking at replacing the servo innards with a PIC miconcontroller but i need to get a programmer first :P

So that would mean that a servo simply splits the signals out into its component pwm signals then?

Just interested, cos I've been thinking about this myself.

Andy

[john_frizell]

Re: new robot

i was thinking of having a r/c car and puting a armor shell over it

One view is that this would be a monumentally bad idea. Another is that it is a good way to start. If you do go this way, use a cheap r/c car from a boot fair or the Friday ad. It is certainly a good way to get you into the arena but it will not last for long.

[muchalucha]

Re: new robot

been going down this road for quite a while now and im pretty sure ive got a decent saleable product . I tried making the speed controller in the link and although it worked , it quickly became apparent what a pain in the arse mosfets are . also they are expensive and i was going for a real budget esc.

The servo board is taken out and a 4.7K preset pot is fitted to give fine trimming control. 2 doides are used to split the pwm signals to the motors and the 5 V singals are fed to the Darlington array , the relay coils are fired on 12 V from the darlington array. It gives very crude speed cotnrol but its amazingly controllable and although itd not as good as maybe a sabertooth , it rivals it and is one hell of alot cheaper.

All parts can be bought from techno bots for around 30 quid.

I have dubbed these team thants esc's. There are 4 currently in existence and countless prototypes , jack orr has one and i have the other 3 so after ive built a few more ill publish circuit diagrams and sell them at around 30 quid .

some specs for anyone interested:
1.5A BEC
input voltage range 6.5 V - 38 V
15 A continuous 45 A peak ( itll run 2 drill motors no problems)
dual channel esc
fited with connectors of your choice !!!
supplied in aluminium box which does get hot on the left side due to regulator

[daliad100]

Re: new robot

I'm interested in this

[RogueTwoRobots]

Re: new robot

£30 for a dual esc? Does it provide proportional drive? (can't quite tell from above posts sorry )
If so, I'd be willing to try one out in Drumroll for that price, it doesn't have the most demanding drive so would be interesting to see how this controls it.

[muchalucha]

Re: new robot

it does have some degree of speed control as by puching the stick a little bit , it pulses the relays which moves the motors slowly , you best bet is to ask jack if you can see satanix go , its hard to describe without showing you :P. obviusly relays dont like being pulsed too much which is why i have rated this controller significantly under what it can achive.