Overview

O.K,

Been on the forum for about to weeks now. Thought Id post up an overview of what I am planning to build. I have been researching since december 07 but Im still a bit rickety with some concepts.

Name yet to be decided

Motors: There have been recomendations to use cordless drills - are there any I can find cheap, and will I need two (with chain drive) for a fast rammer/lifter or four?

Batteries: Overlander, Sanyo 2100 12v C NiCads. Its 595grams and provides a max discharge rate of 40 amps. It is 217 x 46 x 23 mm. Taking into account width and weight restrictions how many will a need with a) Four motors and a simple actuator (with a built in battery pack but Im going to overvolt it) and b) Two motors and a simple actuator.

Speedo: Scorpion XXL, or Sabretooth 25A. Will I be able to control the motors and an actuator with a single controller?

Actuator: A slow, cheap Chain actuator, just bolted to a hinged piece of metal. Probably TopMan services, or maybe a vent engineering one overvolted from 24v to 36v by an extra battery pack - is this last specification sound? It will be the built in battery pack, probably alkaline, overvolted by nicads or will I have to change it?

I am hoping the finished design wont look too much like wedge of doom, but that is what Im basing it on - albeit a rather primitive version.

Thanks,

Alex R

Hi Alex

Well drill motors are a good idea but i dont think they give much pushing power from expierence. With them you get a gear box so you dont need to complicate things with chains. I you want to have 4wd go for 4 drills.

You are able to overvolt drill motors so i would go higher than 12volt, and a higher mah if you want to run all that from it i use for 2x12volt drills and a bosch 35w lifter 2x NiMH 8.4v 3400mah and they will last an event

Speedo: Id say scorpion xxl becuase you will have more options later on, also another controller is needed for the lifter an electronize switcher with micro switches if you dont have limit switches in your linear actuator. if you have limit swthces a normal drive elcrtonize speedo will work

actuator: i have never heard of a chain actuator so would need more info on that. i would stick to one sort of battery type per robot it makes things much easier. can i ask why you want to go for an acuator with a built in pack? wht does this weigh?

Your on the right lijnes though go to see you doing reserach very good skill in thsi hobby!!!!

can you give us so more info?link to the actuator site please?

thanks hope this helps

Alex M

Yeah course coming right up.........

http://www.topmanservices.co.uk/index.php?main_page=product_info&cPath=14_6&produc ts_id=25http://www.topmanservices.co.uk/inde...Path=14_6&prod ucts_id=25

well looking at that it doesnt look like the norm of robot actuators due to the shape and the chain drive thing??

also i would personally for the money want more than 40kg of push

how about this? yes from the us but its just an example

you could double the votage which would then x4 the force giving upto 2.4tonnes i think that might be wrong with my clculations but on 12volt its still powerful

thats what i would call a usual linear actautor

http://cgi.ebay.com/NEW-INDUSTRIAL-LINEAR-ACTUATOR-12-VOLT-ACTUATORS_W0QQitemZ330275819674QQcmdZViewItem?hash =item330275819674&_trkparms=72%3A570%7C39%3A1%7C66 %3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14http://cgi.ebay.com/NEW-INDUSTRIAL-L...RS_W0QQitemZ33 0275819674QQcmdZViewItem?hash=item330275819674&_tr kparms=72%3A570%7C39%3A1%7C66% 3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

So this thing is 12v? And does it have its own battery pack or does it need to be run by something? It has no specs that I can see. And how slow is it because the reason I went for the chain actuator was becaus it was 3 times the speed of the others. And if all Im doing is lifting a 13.6kg robot then surely I only need 40kg of push? What are the advantages of having any more?

So should I Double the voltage to 24v, and does this thing have a built in battery pack, or do I need a 24volt battery?

Should I use cordless drill motors? How many? Or would it be better to use something more industrial?

Thanks mate,:proud:

Alex R

for the drive use the drills

the actuator i posted was only to show what is usually used in this hobby, yes foir a lifter 40kg is fine but if you wish to build other robots like many you may make them from older robots, so if you got one i suggested then you have more options in the fiuture

no it wont have its own battery pack i think it is better to get one like this as you are paying for a battery that might not be suitable etc

How many drills?
And how many battery packs will I need?

thanks,

Alex

2100mah should be enough for a basic featherweight, how many packs will be determined by what voltage you want to run at.

well thats really upto you drills arent expensive but if you have 4 rather than 2 thats more weight more wheels bigger robot more weight again but probably better control

when you say how many battery packs that rather depends on the battery packs themeselves

i would personally go for either 2x 8.4volt packs or 2x 7.2volt packs with 2500mah + i would say per pack

alex

I was looking at 12 volt overlander batteries - is the figure youve given me per drill or for the whole robot inc. the actuator?

I think Ill probably use four drill motors - but Ill have to do a bit more research :lame:

Thanks Joey and Alex

Alex

40kg of push? I wouldnt bother. Consider that you will have mechanical loses etc associated with lifting and then there is the fact that you could be lifting more than one machine at the same time. 3 feathers on that and you will be probably be burning it out and looking for another.

My advice when it comes to robots is to overengineer as much as you possibly can.

So are there any actuator sites that I could use then? Cheap? Are two 12volt packs enough for four drill motors? Then a 24volt one to over volt the 12 volt actuator?

Does anyone know a good site for buying transmitters, 24v batteries and cheap drills?
Do drills come already geared or will I have to use chain reduction?

Thanks :proud:,

Alex R

try ebay for the actuators they will be 2nd hand but cheap enough and most will be powerful enough

aslong as you get a good mah for the battery packs you can run everything from both packs inc the actuator

contact either james or grant copper for a spektrum set (transmitter and reciever)

cheap drills BandQ etc just get their own branded ones cheapest there. and when you have we can help with taking the apart advice etc they come with a gear box attached no need for chains!!!!!

alex

http://www.technobots.co.uk/http://www.technobots.co.uk/

For drills, the cheap ones from Argos are generally good enough for robot purposes, theres a lot of topics in the FW archives about modifying them.

thanks, Joey would it be possible to have a link for the drills? I am the most computer morbid person in the world :proud:. What kind of Mah am I looking for? And if it is good enough you say I can run EVERYTHING from two packs? From two overlander packs?

Sorry to keep questioning you but Im dying to start but I want to research it properly first, and trying to get as much as I can from this thread.

Thanks,

Alex

http://www.argos.co.uk/http://www.argos.co.uk/ :proud:

Asking on here might get you some as well, lots of people looking to make a few quid from excess gear...I mean, to help new roboteers get started in this sport :proud:

Ok cheers for that :proud:. Are the drills already geared? And I probably need to buy some, small tough wheels so that I can work out the gearing formula. How many packs will I need for the actuator? Just the two?

Thanks,

Alex R

The drill motors come with the gearbox built in, that is the main reason why a lot of people use them :proud: Some people can sell you wheels that fit directly onto the drill motor axles, these should be good enough for most purposes.

Heres a link for you Alex R ..
http://www.robowars.org/wikka/DrillHacking101http://www.robowars.org/wikka/DrillHacking101

This forum is great! I have learnt more from this forum in the last two days than all of my research! Thanks for the link Woody (Did you build onslaught?). If I was to use four of these
http://www.argos.co.uk/static/Product/partNumber/7104899/Trail/searchtext%3EDRILLS.htmhttp://www.argos.co.uk/static/Produc...rchtext%3EDRIL LS.htm
would that be O.K?

So that I can work out what wheels I am going to use please can I have a formula for a) RPM to speed with x sized wheels and b) A formula for torque.

Thanks a lot you lot,

Alex R

beauty likes the £10 ones they are cheaper

(make sure the wheels are on tight they fall off !!!) i h8 them girly robot drivers

Locktite is also good for the wheels it is rather embaressing when someone asks you to drive to the middle of the arena and the wheel unscrews iteslf before you get there!!

Andy

Hi Alex R,

Yes Onslaught is my old bot.

Links:-

http://www.4qd.co.uk/faq/roadspd.htmlhttp://www.4qd.co.uk/faq/roadspd.html

http://www.teamkiss.com/builder.htmhttp://www.teamkiss.com/builder.htm

http://architeuthis-dux.org/torquecalc.asphttp://architeuthis-dux.org/torquecalc.asp
Pick a Harbour Freight Drill as your drive.

Woody

So what wheels should I use?
About what diametere with a 550RPM drill?

Thanks for the links.

Alex R

Alex R.
Take the http://architeuthis-dux.org/torquecalc.asphttp://architeuthis-dux.org/torquecalc.asp link

Pick the Harbour Freight 9.6v Drill

Youll see a box with :-
Voltage Constant[ ] RPM/volt simply divide the drills rpm by the voltage 550/9.6 = 57.29 and input this number into the box... Its actually pretty close as it is ... 55.6 x 9.6 = 534 rpm

Pick 30lb bot... 6 wheel... 1:1 Ratio and 2 motors per side ( 4 wheels driven )

Play about and alter the parameters of voltage ... wheel dia and number of motors per side.
E.G. 12v instead of 9.6v and 5 instead of 6 wheels etc ...

Note the changes ouput by the calculator....

It even gives an estimation of the required battery pack Ah.
The biggest problem with drill motors is IMO is the Stall Amperage ...Speed controllers can cut in and out if they have current limiting.

(Message edited by woody on October 08, 2008)

Thats a very handy calculator you found there Woody! Nice one!

Erk.... Thats quite slow....I was lookin more in the region of 20 MPH rather than 9. Is there anything I can do to solve this?

thanks :proud:

Alex

DOH!....courier newcourier>I said +1>PLAY with the numbers.

Try.
BIGGER WHEELS!
OR
A faster donor drill or try overvolting by say 50% max.

I knew that:proud:. If I overvolt it wont I overheat it? I think Ill have to look for new drills, Im not prepared to use larger wheels. If I overvolt it by 50% will I get 50% faster rpm? And are there any faster drills anywhere?
Links please.

Thanks you:uhoh:

Alex

Three questions ...Yes ( but not enough in general to worry about )... Yes and Yes.

http://www.google.co.uk/search?hl=en&q=cordless+2+speed+drill+rpm&btnG=Sea rch&meta=cr%3DcountryUK%7CcountryGBhttp://www.google.co.uk/search?hl=en...btnG=Search&me ta=cr%3DcountryUK%7CcountryGB

Danke Schonne :proud:.
Will need that. Merci.

Grazie,

Alex :proud:

P.S Corrections on Danke schonn? I think I miss -spelt it.:uhoh:

EDIT: Will this be O.K on the torque front?
http://www.argos.co.uk/static/Produc...t%3EDRILLS.htm

(Message edited by aero_storm on October 10, 2008)

That is a corded drill and so works off 240AC not (as you are allowed in the rules) up to 36V DC.

A simple rule. If you plug the drill into the wall, it isnt useful to you. If it has a battery that needs recharging every so often and is in the voltage range of 9.6V to 36V it is useful to you.

O and stay away from hammer drills. Stopping the hammer motion is a bigger hastle than its worth.

(Message edited by typhoon_driver on October 10, 2008)

Ok. What about these. I know Im just throwing links around but this is a forum.

Thanks for the advice about the plug although the problem probably would have become clear once I had bought it :)

http://www.argos.co.uk/static/Product/partNumber/7106127/Trail/searchtext%3EDRILLS.htmhttp://www.argos.co.uk/static/Produc...rchtext%3EDRIL LS.htm

http://www.argos.co.uk/static/Product/partNumber/7111686/Trail/searchtext%3EDRILLS.htmhttp://www.argos.co.uk/static/Produc...rchtext%3EDRIL LS.htm

http://www.argos.co.uk/static/Product/partNumber/7110340/Trail/searchtext%3EDRILLS.htmhttp://www.argos.co.uk/static/Produc...rchtext%3EDRIL LS.htm

Thanks,

Alex R

Ill throw a link back at you ...one that I gave before ...http://www.4qd.co.uk/faq/roadspd.htmlhttp://www.4qd.co.uk/faq/roadspd.html

Put in the cordless drill RPM ...1,200
You will be screwing a wheel on in place of the drill chuck so ...Gear Ratio = 1

Use a wheel dia of 100mm

Output = You tell me Alex R :)

Id really like you to try and use the calculators.

The above rpm and wheel size is fairly common if your using cordless drills as drive motors.

Woody

The reason I was asking for more drill links is because the speed that a 1100 rpm drill gives me with 4 inch wheels is about 13 mph. So I have, in fact, used the calculator, and done everything you have told me to do on the calculator. This is a forum. Im not as experienced as you, but if I was I wouldnt be here.

Alex

quote:

Im not as experienced as you, but if I was I wouldnt be here. Thats not a great attitude, just leaching of the knowledge of others because you havent yet. So the second you know all you need youre out of here?

I knew that would be thrown back in my face.

No, thats not what I meant. I do appreciate the help Im getting. I was a bit irked due to the fact that despite trying my best I just wasnt good enough. But, hey, Im not experienced, I have built no robots, so Ill take what comes.

Alex

P.S Back to the topic now?

P.P.S Sorry :blush:

(Message edited by aero_storm on October 11, 2008)

Alex R ...I happily make allowances for newbies ...young or old.

Whilst I could have given you the specs for everything ...I believe its a good idea to at least make you do some homework on the subject.

So homework done.

I think for the price range your looking at ( cheap ) perhaps 4 off 9.6v drills run @ 12v with 100mm wheels giving you approx 8 mph.

Getting the higher 1000 plus rpm will probably require you to double or treble your £ spend.

Ok, thanks. My calcs say that if I overvolt a 750rpm motor with 7cm wheels, I get 13mph. This is what I will go for. Then Ill just see what happens.

Alex