I have some more questions if anyone gets a sec

[daveimi]

I have some more questions I could do with answering if anyone has a minute. I've tried to save them up so as to minimise the chaos, have searched for the answers but haven't got the specifics I've needed. They're a bit general...here we go...

1. Is it feasible to do a whole event with a feather on one big SLA? My simple pushy robots never weigh much when finished (circa 8-10kg) and have low powered motors. I was umming and arring about sticking a ginormous SLA in that's rated at say 12Ahr and seeing if I can just turn up with robot and toolbox and have an easy life.

2. Cradles...is something like some 2x2 nailed together suitable as long as it keeps the wheels off the table/bench/ground etc?

3. Wheelchair motors for a featherweight axe. Originally bought a wrecked wheelchair for the running gear to put in a naff heavy weight. At the time I just bought the chair on a whim as it was going to the scrapyard the next morning if not. Since dragging it home, stripping motors down to remove magnetic brakes etc I've become disillusioned with the cost of building a heavyweight. I was looking at ways of re-purposing the wheelchair stuff (bearing in mind each motor assembly is around 7kg) into a feathereight. Would it have enough torque at 250W to roll a hammer-bot back onto wheels if I make the body a low curved shape etc? Am I better just giving the wheelchair to a builder who will make better use of it? Should I save up and have a crack at a cheap heavyweight?

4. Bigger wheels with 3/8 unf thread. I've had a mare trying to build within the confines of 100mm blue wheels. Does anyone know of anything bigger, say 200mm with a unf thread? I'm umming and arring about making my own wheels e.g. 200mm hdpe circle with 8mm hole drilled in the centre threaded onto chuck output shaft, bike tread screwed on. If anyone has found anywhere doing big wheels please lemme know / discuss / comment better way of making home-brew wheels.

5. Based in Blackpool. Any other builders with something running from the Fylde / Preston area fancy meeting for a car-park street-fight / generally getting to know some fellow builders in the area to swap parts/knowledge? I know the Big Nipper team are from up this way but so far have been too shy to get in contact. Email to The Jammy One yielded no results (don't think he's been on-line for a long time).

6. Fail-safing Tx/Rx combo. Back when I was getting sorted with cheap everything to get up and running all I could afford was £20 Giant Shark handset. Since now realising it doesn't failsafe all that well, and having tried a posh external failsafe with no joy, can anyone recommend a nice set that failsafe's on all channels. I have around £100 to spend and am seeing this as an investment. At the minute the hot favourite is a DX6i with an Orange Rx. Please can someone with experience of these confirm they do failsafe all channels to a neutral position. And if so, which specific model numbers should I be watching out for?

Thanks again.

Dangerous Dave.

[Pinski1]

I'm also interested in a TX/RX combo that would be acceptable.

[razerdave]

1: Honestly? No. The SLA's that are feather size were not designed with a lot of current draw in mind (made for low draw fire alarm systems and such). You would be better off with some Nimh batteries from ComponentShop.co.uk and getting a decent charger.

2: As long as it's in a form that the robot can't just slide off, it should be fine

3: For the weight, you'd be better off with a 300w scooter motor (look up Onyx in the RogueTwo robots build diary).

4: 200mm wheels for a feather is rather excessive, but not unheard of. If you want to make them that size, probably best to make them from thick sheet plastic and make a hub they can bolt to that has the required thread on it. Best person to talk to about that is Craig Colliass from Saint.

5: The Explosion/Eruption boys are from that area

6: If you buy the Orange T-six or a DX5e (spektrum) and pair it with a big 6ch orange RX (set up correctly) will give you fail safe on all channels (I'll link later, on the phone ATM).

[Anttazz]

On the SLA front, it depends on how competitive you want the robot to be. The Scot-Bots use an SLA, the ones we use for demo's use 2 SLAs and we've run them for 3-4 days without needing to charge them. Obviously if you're looking to win the UK Champs with it then the extra weight can be better used elsewhere but if you just want a robot that you can throw into the arena without too much work between fights then they're not too bad.

SLA + Wheelchair motor is pretty much the entirity of your weight though , so if you're going down that line then you'd want something lighter. Jamie's had a battle getting Onyx in weight and using a Li-Po it scrapes in at the weight limit (sometimes). Like I said before though, if you're not entering it into the UK Champs if its a few grams over weight it won't matter too much, especially if you have all of the stuff you want to use sitting there already.

[razerdave]

I honestly thought the SLA would not be much cop to be honest, my old ones didn't last that long o wiper motors...

[daveimi]

Thank you for the replies! The idea of a big SLA was a pushy robot, I know I'm never going to win the champs etc. so wondered about a dead easy life at day long events lol. With a hammer I would have to be clevererererer about the weight use.