Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
#25 sprockets go down to 9 tooth, which is under 19mm - probably not from a pocket bike supplier though. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Sep 23, 2015 2:30 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
Yeah bud, give this a try, i think this is Shane's business? He used to be on the forum under Bytraper, maybe drop him a message
The pocket bike pinion sprockets go all the way down to 6 tooth and have an m8 thread on the end, but the 200-300w scooter motors have the same pitch chain too, those sprockets might be handy.
just be really careful with chains and alignment, they love to run off in robots _________________ Mechanical engineers build weapons, civil engineers build targets
Wed Sep 23, 2015 4:55 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
What he said! If you can fit it in, a tensioning device will help keep the chains on. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Sep 23, 2015 7:01 pm
andrew
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
Just mount wheel direct.to motor and skids maybe? _________________ Andrew Welch, Team Unconventional Robotics
Wed Sep 23, 2015 7:26 pm
Jaemus Experienced Roboteer
Joined: 01 Apr 2009
Posts: 2674
Location: NSW
4WD full body spinner, very cool. I say stick with 4WD, it will help it to be stable and drive in a more predictable fashion and when the weapon system fails you'll have some pushing power. Chain or timing belts would be my suggestion also _________________ <Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls
Wed Sep 23, 2015 9:10 pm
shreddy
Joined: 09 Jan 2009
Posts: 518
Location: Wantirna, Melbourne
I like the robot you're building, it's quite impressive (that shell, wow).
Watching the video I was going to suggest utmost caution (I didn't post a testing video a while ago in which brick debris almost smacked me in the face) but then you found that one out for yourself.
I found the problem to be that a shell spinner is constantly firing its weapon in all directions so you really have not much control at all in terms of which directions it's safe to have people in.
Your robot looks to have good potential once you iron out some of the bugs; just try not to seriously injure yourself (or others) along the way _________________ http://au.youtube.com/user/crustydemonsully
The day I stop giving 100%, is the day I stop competing
Thu Sep 24, 2015 12:29 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Joined: 29 May 2012
Posts: 454
Location: Rockhampton/qld
Thanks for the ideas guys I am in Melbourne atm but when I get home will be putting some ideas into action! And she is sitting at 12.36kg atm _________________ Creative Instigation - Build Something Awesome!
Joined: 29 May 2012
Posts: 454
Location: Rockhampton/qld
i have fixed the traction issue!
6WD
(will still be belt driven to the outer wheels) I know the ratio is out but meh running out of time _________________ Creative Instigation - Build Something Awesome!
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
Don't bother
Direct drive middles and use others as castors. Will still drive great _________________ Andrew Welch, Team Unconventional Robotics
Sun Oct 04, 2015 11:05 am
seanet1310
Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide
Regarding self righting.
If you have any extra weight randomly bolt long things on the top until it does self right or at least has a chance to bounce itself back upright as long as it does not stop spinning.
See Badger and the tennis ball as an example. Out of interest, how do you tell forward from backwards?
As for drive, I would be tempted to try Andrew's suggestion. simpler, no belts to fail. Only downside is the side other 4 wheels are chunky so may be a little too much friction. _________________ Remember to trust me, I am an Engineer.
Joined: 29 May 2012
Posts: 454
Location: Rockhampton/qld
i am still going to run belts (pics later its already done) if the belts break they break but i really need all the extra traction i can get atm.
self righting i will play with today hopefully and i was going to put an arrow in the weappon shaft to tell me which way is which. _________________ Creative Instigation - Build Something Awesome!
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