From The Ground Up (Advice Thread)

Sorry for the bump but I can no longer edit my post, I don't think I'll use Speed 900s because I can't find any info on operating and stall torque and I don't want to buy something that expensive not knowing what it'll do. Hmm.

My main dilemma really is that I'm new, but I don't want to design a bot that chundles around the arena and just stops when it hits stuff. But I can't over complicate this thing because I have absolutely no robot building know how.

How do drill motors compare to the motors manufactured for model boats etc? I'm not even sure what motor I want because the only ones I can find don't tell me what there operational torque and stall torque are, and places like technobots I don't even know what I should be looking at. :uhoh:
The tutorials are helpful, but without certain background knowledge on things like motors batteries, what sort of esc I'd need and what sort of speed controller I'd need I'm dead in the water. And it's annoying because I've only just realised. :? It's probably down to that I'm not looking hard enough but I don't even know where to start since half of this stuff makes no sense to me at all.

If its your first robot why not just use the nice simple drill motors and gearboxes? 6 of them will give you a fair bit of power with less hastle and also will be a lot cheaper than buying speed 900's. 4 speed 900's would cost something like £120-160 (not having looked at prices recently) whereas 6 Argos drills will cost you £60 and you wouldn't need to worry about adding in extra gears or anything like that, just whack them on to a set of Robochallenge wheels and you're away.

and that esc and speed controler are the same thing :P

I see your point, like I have said, money isn't a problem and going simple to start is advised (4 graupners = around 170 assuming vat hasn't been added to the 36.99 current price) , but I'd rather make something worthwhile, something that does it's job. After watching a lot of videos online I've noticed how robots tend to sacrifice one thing for a strength in another. The idea with mine was since I'm only doing a rammer, the motors needed to be powerful but I don't need to worry about weapons and I'm a perfectionist, I hate doing things and finding out they don't work, so I never do anything without guidance first. Which probably isn't very good, but there you go!

Did I write that twice? Urghh... :rofl: It's 10 to 9 and I'm extremely ill, it's there fault, blame it on the illness. :shock: :mrgreen:

And would 6 drill motors end up costing quite a bit since I'd need an extra esc plus fan?

I'd have a go with the 6 drill motors in this case and the 100£ ur saving compared to graupners would come in handy when it comes to buying the ESC

Drill motors I reckon are fairly well proven, i'll be using them in a rambot at the UK champs and i'm sure i'm not the only one. The likes of Drumroll I know for certain is using drill motors too and there are many, many others. It doesn't seem like you would be making the machine much better for the hours of work that you would have to do compared to just sticking in a drill motor. Even finding somewhere that sells 18V drill motors or higher would be a more expensive option, but would give you the option of using voltages maybe as high as 25-30V? You would possibly need an extra esc, depending on the esc you are using now. But you would save on have to get hold of gears etc as the gearboxes will be included. If you definitely want it to work, do what has been proven to work :lol:

http://www.clifford-james.co.uk/online. ... iate=8,381

the cheapest 18v drills i could find :)

Ohh, never noticed that before, that will be a good source of motors for me in the future too, cheers Jonny :proud:

Hmm, I see I understand that many robots do have drill motors, but then drumroll isn't a rammer, it's main weapon is a teethed drum, so pushing power isn't as important.
Is Tiny Toon not a rammer? What motors does it run on? Do the majority of the successful rammers work on drill motors? Hmm. I've also heard that with a six wheeled bot you getter better performance from leaving the middle wheel free rolling, is this true? Thanks for all your help so far guys. Sorry I can be such a stubborn toad. :rofl:

Those drills come with a carrying case, what would I do with 6 carrying cases! Answer me that and you'll have changed my mind about drill motors. :crazy: :lol:

Hey Roland,

A lot of comments supporting the use of drill motors instead, and I agree that for a first robot, they are a very good and proven way to go. However Speed 900s are also very good motors and if money isn't a problem and you can go for a decent set of machined gearboxes and transmission, then they will also serve you well.

You talk about having four motors and connecting all the wheels so that if one motor fails the other one can still drive all the wheels. In my opinion, that's a bit overkill. Yes it provides a level of back-up/redundancy and therefore improves reliability, but it's a bit of a waste of weight in a featherweight. Speed 900s weigh roughly 650g so 1.35kg for two, plus extra weight in gears and gearbox housings (could be almost 20% of the max weight); it's a lot of unnecessary weight that could be used to beef up the chassis or armour of your robot. Speed 900s are also incredibly reliable motors from my experience so there shouldn't be much to worry about in terms of motor failure (famous last words though :uhoh: )

If you go for them, I'd recommend a Speed 900/gearbox combo directly driving one wheel on each side, and then slave the other four wheels with timing belts and pulleys. A drill motor pusher is a perfectly fine robot, but you will get a much better, faster, more powerful performance from the Speed 900 arrangement.

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I'm a perfectionist, I hate doing things and finding out they don't work

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I consider myself a bit of a perfectionist too, but in this hobby, you'll find yourself doing a lot of things that end up not working. Learning from them and improving upon them is part of the fun and part of the challenge :)

I haven't used a 6 wheeler so i'm not really sure on that front. Tiny Toon, according to its roaming robots profie, used 24v Gold motors, personally I don't know what they are, but I have heard them talked about on here. I think Gary (typhoon_driver) was talking about them as (I think) he used to use them in Hornet, but I could be wrong on that front.

You could build a fort out of them? Wear them as a hat? Or push them about when you get the robot finished? Could maybe stick them all together and use them as a robot?

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Originally Posted by Anttazz

You could build a fort out of them?

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Never underestimate the fun and awesomeness that can be had from acting like a 7-year-old and building a fort in your living room when you're actually in your twenties and at uni studying to become a respected member of society :lol:

Gold motors were a popular choice for featherweight drive motors many moons ago. They were (not surprisingly) gold-coloured, rated at 150W and available in 12V and 24V versions. They used to be sold by Technobots but it's been a while since they were stocked. I think the Toon machines and DB5 are the main remaining users of gold motors at the moment, although I've probably forgotten several others.

I never used gold motors so I can't truly compare, but I'd be inclined to say that Speed 900s are superior motors.

Well darn you k_c_r I was just falling for the drill propaganda and now you've turned me back to speed 900s again! :rofl:

If I could find an info chart on speed 900s I do a comparison on the advantages/disadvantages to drill motors myself, but I don't have one. So what I'm assuming is one set of two speed 900s + gears and a timing pulley and belt (I know what a belt is but what's a timing pulley? same thing different words?) Would produce less torque and speed compared to 6 drill motors! Less batteries though. :roll: I think if I where to use 2 speed 900s I would have to go back to the drawing board again and design a four wheeled rammer with larger wheels and the pulley as you suggested, which would reduce the amount of axles I'd have to worry about, and weight and cost! :lol: But that would incorporate me going back to my original plans of designing my own wheels, which seems almost more complicated! :lol:

I hate you all and you're complicated ways! :crazy:

Thanks again for your help guys, you've given me loads of ideas! :proud:

I think the only idea that you can take away from this is that building a fort where ever it is you do your robot building is definitely the way to go :lol:

Please, call me Jamie, although I really ought to have picked a better username when I signed up on here.

Speed 900 info chart:

Specification
Nominal voltage 12 V
Operating voltage range 6 ... 40 V
No-load rpm 6500 min-1
No-load current drain 1,1 A
Current drain at max. efficiency 8 A
Current drain when stalled 54 A
Max. efficiency without gearbox 71 %
Length of case, excl. shaft 85 mm
Diameter 51,5 mm
Free shaft length 15 mm
Shaft diameter 6 mm
Weight 645 g

The thing with drill motors is, the specifications of them are often undefined and can vary from brand to brand (particularly in the cheaper brands) so you may find it tricky to accurately compare the two.

Think of a timing belt and pulley system as a chain and sprocket system. The timing pulleys are like sprockets but tend to be thicker and have less pointed teeth. Actually, a picture speaks volumes: http://www.technobotsonline.com/synchro ... 33901.html (as an example)

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Originally Posted by Anttazz

I think the only idea that you can take away from this is that building a fort where ever it is you do your robot building is definitely the way to go :lol:

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Not too shabby either! :rofl: I could use the spare drill bits as ammunition of any one ever dared enter my workshop again. I doubt I'd ever run out of them either :lol:

As a side note, since I have a welder in my workshop, which has windows that open up to the garden; where can I purchase some of that red covering for the windows to stop the flare from damaging anyone's eyes? Is it anything specific or is it literally, transparent red plastic sheeting. :lol:

Ah, that's the same date sheet I had from Red Bank but it doesn't mention torque anywhere? is that the same as operating current and stall current? I need to learn some formulas!
Sorry about that Jamie, I had no idea, calling people by there first name always seems to informal, and I don't want to offend anyone!

Out of interest do edits bump a thread? I'm manually bumping because my edit was essentially a separate post, just so I know for next time! Sorry.

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Originally Posted by Roland

Sorry about that Jamie, I had no idea, calling people by there first name always seems to informal, and I don't want to offend anyone!

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Not a problem Roland, that's what my first name is for :)
I can't help you too much with the sheeting to reduce welding flare, but maybe have a look around the likes of Machine Mart or welding specialist stores, or even a quick Google search might throw up something. Failing that, you could just eat several strawberry creams from a tin of Quality Street, save all the plastic wrappers and weave them into a patchwork covering :P

And no, edits don't bump a thread or show up as a new post, so if you've added some information that you feel is relevant but might have been missed since it was edited in, a manual bump is an option, either by posting again or by hitting the 'Bump topic' button that should be near the top of the page (only works for the thread creator I think)

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Originally Posted by k_c_r

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Originally Posted by Roland

Sorry about that Jamie, I had no idea, calling people by there first name always seems to informal, and I don't want to offend anyone!

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Not a problem Roland, that's what my first name is for :)
I can't help you too much with the sheeting to reduce welding flare, but maybe have a look around the likes of Machine Mart or welding specialist stores, or even a quick Google search might throw up something. Failing that, you could just eat several strawberry creams from a tin of Quality Street, save all the plastic wrappers and weave them into a patchwork covering :P

And no, edits don't bump a thread or show up as a new post, so if you've added some information that you feel is relevant but might have been missed since it was edited in, a manual bump is an option, either by posting again or by hitting the 'Bump topic' button that should be near the top of the page (only works for the thread creator I think)

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But I think the real question on everyone's lips is, how many wrappers would a rapper wrap if a rapper could wrap wrappers?

Thanks for the help, and everyone else who has contributed to this thread thus far, you've all been very welcoming over these past few months. :D
I'm going to buy 2 speed 900s tomorrow to seal the deal, after that I'll look into buying the rest of the components, I think it'd make sense to look at wheels and armour last to be honest.
I have a thousand more questions to ask the forum but I'm going to let it lie for tonight since I'm sure you're all bored of my puny mechanical intelligence. :roll: :lol:
Thanks again!

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But I think the real question on everyone's lips is, how many wrappers would a rapper wrap if a rapper could wrap wrappers?

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Now now, thats just silly :lol:

The trouble with speed 900's for ne is how do you keep them cool and get a gear box in? Chain drive or timing belt pull systems?

I never bother working out how to keep motors cool. Let them get hot during the 3 minutes of combat and then cool after. Gearboxes, mario has some nice single units that he made a while back I believe from some steel plate. It's a more complex process making your own gearbox combo than just using a drill motor.

I learned this the hard way back with hornet 1. Decided to be smart and not use drill motors and use golds instead. Made some nice little wheel box units but those weighed more than a drill motor and i didn't notice a great deal of difference in the performance to be honest. Although I may crack them out at some point again.

Just another quick off topic, but where can I find somewhere were I can see pictures of the bots you guys have built? Build Diaries is useful and interesting but it's always cool to see static shots of ideas people have thought of and built.

And back on topic:
What batteries do people tend to use on graupners anyway? I'm assuming two of these: http://www.technobotsonline.com/ansm...0mah-nimh.html
per motor would do, or would I need something with a larger current? Do you generally have spare batteries for after combat if you do manage to get through without wrecking your bot and you have to enter again? Or do you just run the battery dry and then recharge the ones you just used?

http://s31.photobucket.com/albums/c367/ ... ps%202010/

Jamie has been good at taking and uploading pics for various events. Check out some of his sub albums for various pics.

Thanks! That was exactly the sort of thing I was looking for. :)

for welding screening the focus is not allowing uv light through so as long as whatever you put there stops uv getting through then it should be fine. remember you need decent air circulation though as gasses given off from welding can be toxic. as for robot pictures i tend to just look through photobucket and rr database :)

Hmmm. I could probably just stick up bits of cardboard over the windows while I'm welding. Probably cheaper too. :D
If I had one dual speed controller would that allow me to still have tank steering? Or would I need separate solo speed controllers? What are the best quality ones to buy?

Thanks everyone. :)

It would yes, some of duel speedos have different settings to let you choose what type of steering. The Sabertooth and the Scorpion XL apparently do anyway.

I use drill motors and a 3300mAh battery in my first robot and it worked a treat. I would really recommend them and they are the best for new roboteer's
By the way this is the inside of my robot:
[attachment=0:23g9qnsm]untitled 2.png[/attachment:23g9qnsm]

Aaah. Thanks :) Well, I just need my battery question answering and I can set out my shopping/check list. :lol:

Edit: Didn't notice the picture Ben, looks awesome! How many batteries did you end up buying?

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Originally Posted by typhoon_driver

http://s31.photobucket.com/albums/c367/ayrshirerobotics/UK%20Featherchamps%202010/

Jamie has been good at taking and uploading pics for various events. Check out some of his sub albums for various pics.

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Yeah one thing I always enjoyed when first getting into this was seeing pictures from events, particularly bot innards, so I try to do the rounds at each event and get some pictures. I'd prefer to have more action shots but my camera doesn't seem to have an ideal setting for them and they usually end up blurred. Not been as much of an issue since I've had my video camera.

The build albums I've got on that page are quite extensive for the likes of Drumroll I and Kaizer Mk.2. Back then I used to take a photo whenever I fitted a bolt or secured a part as I considered it incredible progress! :P
Now my machines tend to go together much quicker so the more recent albums have less photos and less detail. Hopefully they're still a good resource though for people such as yourself to see different set-ups and build techniques.

With regards to the batteries; I've only ever used two Speed 900s as weapon motors before with quite light gearing, but the robot at the time used two 9.6V, 3700mAh battery packs. I don't know how much more/less current they'll draw when used in a drive train but most Nimh packs (Vapextech are a pretty good brand) will be sufficient. You would notice a difference (improvement) if you used some form of lithium batteries but I think for your build, Nimhs are the best way to go for starting off.

http://stores.ebay.co.uk/Vapextech-Batt ... d-Chargers

And as Gary has mentioned, don't worry about cooling. The Speed 900s will cope with a 3-minute battle and can be left to cool after fights.

I'm using 1 12v 3300mAh NiMh battery it works fine. I'm getting another one as i'm making it 4 wheel drive.
I'll just go and find the link of the battery shop and some other batterry's.

Vapextech http://stores.ebay.co.uk/Vapextech-Batt ... d-Chargers
Century UK http://www.centuryuk.com/Products/Tools ... s/item3549
Component shop ebay http://stores.ebay.co.uk/Component-Shop
Component shop http://www.component-shop.co.uk/

Ok, so my checklist so far goes something like:
6* 125mm Robo Challenge blue wheels
2*Graupner Speed 900s
2*http://cgi.ebay.co.uk/12V-3700mAh-Ni...item3353ee4e1a
1* Transmitter and Reciever (Not sure where to go yet or what I really ought to buy)
1 * skorpion xl + cooling fan? or does that go the same way as the graupners that they will cool themselves?
1*Resistor and LED
1* safety removable link
2*1:50 gears for graupner motor, where should I look?

Not going to look at pulleys until I've worked out how big this bots going to be, that goes for armour etc as well!

Please mention anything I haven't said or should change to something more fitting. Thanks guys! :D

Off topic - Jamie, what CAD did you use to design drumroll, and the robots in your misc album in photobucket, and how much did it cost?

If you are after another I have 2 6v 3300Mah vapex packs up for sale in the for sale section.

Running two drills and two speed 900s for 4 fights only took around 2Ah out of a set of lipos. More efficient than nimh but that should give you a rough ball park figure of how long your bot could run for.

Funny you mention the albums jamie, i took a look through the drumroll one. Funny seeing how far it's come since then ;)

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6* 125mm Robo Challenge blue wheels

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These wheels don't come with nut insert.

i highly doubt a scorpion xl will be able to handle 2 speed 900's even with a cooling fan. i'd go for atleast 2 30 amp electronizes.

Best if you use 2 separate ESC's like 2 SyRen 25a

Yeah, I just noticed the limit was 24v on the skorpion xl! :lol: Thanks anyhow. I'll look at the others in a second.

Hm, I see what you're saying Gary but I think I'm better off going bigger if I can afford it to be honest, the longer it'll run the better.

So the 30 amp ones are borderline then Johnny, or are they advisably better?

you won't take much out of a set of nimh even if you run something serious. Running a mag off a set never took more than an amphour out of the batteries in hornet 2