Starting Point

Hi this is to be my first build, never having built a robot before I am unsure on quite a few things but initially so I can start to get the basics I want to build a very basic robot so not worried about which weight class it fits into for now and then go on to build another for fighting after I have the basics.

First couple of questions are;

I see alot of people using drill motors, how much power do these provide, ideally id like to be able to push a small child round on it, would I therefore need something abit more powerfull like wheel chair motors for example?

Obviously I need a transmitter, what is good starting point, after reading the forums I see most people saying DX6 or planet 5 can anyone recomend either of them or another one entirely.

First of a decide a weight class , from what you have said id recomend a feather weight.

some fetaher weights ( FW's) can push around a small child but 2 drill motors wont be up to it. If you want something with more power consider 2 electric scooter gearboxes or look at gold motors ( ask around).

As for the transmitter , planet t 5 2.4 ghz set £ 35 and you got a transimter receiver and on 2.4 ghz !!!

Good luck and welcome to the forum btw :).

Cheers for the quick reply, I initially didnt want to limit myself to any weight class so I could just get to grips with the basics and then go on to probably build a FW.

Ive found the following links to motors, are they any good?
Technobots Feather Gold 12V 150W:
http://www.technobots.co.uk/acatalog...Motors_76.html
Scooter motors:
http://cgi.ebay.co.uk/24V-250-Watt-E...item230300239e
or Wheelchair motors
http://cgi.ebay.co.uk/Electric-Wheel...item1e591a48a7

Any with regards to the transmitter its not rli worth me spending extra and getting a different one? (I am on a budget but dont want to buy something thats only good once)

hey,
i would really recommend you look at all the build diary threads to have a look at how other people have gone about making their robots from feathers to heavyweights.

when i first started there was nothing harder then trying to find out what to do or what parts i needed - theres only so much that can be explained to you and looking at alot of build diaries i think would have been very helpful

i would recommend using cordless drills to start with, as they are near enough ready to attach a wheel onto once you've taken the chuck off.

i'd say get a dx5e for £70 or so, the cheaper £35 sets might say 2.4 ghz but they arnt always very reliable or of a good quality- people were talking about it on a thread a while ago somewhere on here.

if you went with 2 drill motors you would need 2 electronize speed controllers here, http://www.electronize.com/ one each of the 15 amp high power forward and reverse controllers,

then theres batteries either sealed lead acid batteries which is what i first used in my first robot, but you soon end up getting better ones and they will just get chucked on a shelf or NIMHs which are what i use from the seller vapertech on ebay.

there was a guy in a similar situation as you a few weeks/ months ago so you could mabye try finding his thread as theres aload of useful info on there.

sorry calum but im going to completely disagree with you :P.

I have used the planet T5 and the spektrum dx5 and i prfer the palnet t 5 , regardless of price. The dx5 feels cheap , its too light and just dosent have a nice feel , also the binding method is rather questionable. The planet T5 though feels a lot nicer , it is nicer to hold and use. This is purely subjective, but as for the interferance problems people have created about the planet T5 , well im gona say thats rubbish until any set produces any type of interferance :rofl: ( hasnt happened yet).

As for motors , ifyou are definitely sure you want this bot to carry children (lol), then scooter motors would be your best bet. They are simialr to drill motors in that they come pretty much pre assembled witjh all the gearing done for you , but they have more power. If your after true power then a pair of gold motors would be good , but you will probably need quite a bit of help on the gearing.

As weight seem unimporant in tyour application id use the sla batteries that come with your scotters or the nicads that come with your drills. Youll get an acceptable run time and you get a charger to.

As for the esc's , if you have a veyr big budget and you dotn require that mcuh fine cotnrol then , (this pains me to say) get 2 electronize esc's. If your budget is smaller and you decide to go with drill motors then a sabertooth 10 A will be fine. If you end up using scooter motors or gold motors then a 15 A electronize is going to be right on the limit ( they relays in them are only rated to 10 A anyway !!!!!) . You coudl always use a switch or relay based system for any of these motors if money is tight.

EDIT: As for the wheel chair motors , they might be a little over kill and any bot you decide to make out of awheel chair is going to have to be a heavy weight , and tbh , no offence but its a bad idea to build a hevay weight as a first robot.

Hi Matt,

Welcome to the forum; plenty of advice to be had on here as you can probably see :)

Normally I would echo others on here and recommend a featherweight but as you've stated that a) you'd like to have enough power to push a kid around/let a kid ride on it and b) you're not too bothered about a weight class right now, then I think bigger is better in this case.

To have enough power for the 'kid' aspect, either wheelchair motors or scooter motors are the way to go in my view. Wheelchair motors can be quite cheap (like off eBay as you've posted) but are quite slow, so if you want power and speed then the slightly more pricey scooter motors are a good option. In most cases wheelchair motor assemblies are complete, in that they are a motor/gearbox/wheel in one; with the scooter motors, obviously a gear reduction method would be needed. Technobots has a good range of chain and sprockets for a pretty good price and Paul Cooper, the owner, has extensive experience of this sort of stuff and would be able to provide useful information or insights as to what would suit your project best.

What skills/tools do you have at your disposal? If you can weld, a well-designed fabricated box-section chassis would stand up to the punishment that robots take and wheelchair and scooter motors could both be welded or bolted in easily enough.

For radio gear, I'd say you can't go wrong with the Planet 5 system. It's 2.4GHz, and £35 so well suited to a budget. There have been concerns that the signal could be prone to interference due to it being seen as an 'inferior' substitute to the well-respected Spektrum range of equipment, but to date I can gather it has performed well (I currently don't own one myself)
Check out the 'safety issues' thread in the Safety Discussions section to read some posts on the topic.

I'd be best leaving batteries to someone more experienced in heavier machines, as I'm primarily a featherweight builder and am not too sure what is best/required for larger weight classes. You can't go wrong with sealed lead-acid batteries to be honest, but with the low-ish cost of A123s etc, the modern technology could serve you better.
What I will say is that batteries (and speed controllers) is an area where it's usually better to spend a bit more and get a better quality product that will last you longer and can be used in future builds, rather than something that might 'crap out' on you after a little bit of abuse.

Hope that helps you a bit, and good luck with your build :)

What weight is the child? When you say push around, are you after a radio controlled equivalent of one of those electric cars that you can get for kids but with a bit more oomph?

If you wanted to push a small child around, I recommend using four drill motors for 4 wheel drive. Will Thomas's robot whirlpool uses this configuration and can push me around (we have tried it), and I'm no small child. I'm 16 and about 60kg! As to ESCs, I'm not sure, but electronizes are reputed to work with four drills. Other than that, I know that a Scorpion XL/XXL would work, but they are quite expensive.

Thanks for all the great advice so far it been really helpful. I said I wanted to be able to push a small child around not because I actually wanted to do it but because I was kinda unsure how best to describe what sort of power I wanted it to have. In rexs robot challenge I saw him ride on his and thought thats a fair amount of power, how much weaker are drill motors than this?

I dont currently own the materials or the skills to weld, I wondered if it was worth learning as I'm reasonable young and would probably do a lot more things like this. What is the cost of gear ect?

Thanks again, matt

Hmm I really like the sound of 4 drill motors, would the Electronize: RC Speed Control 40A work as a controller for it?

As far as I know, the 40a version doesn't do reverse, so I don't think so

Which version do I need and how many of them? Also would the cheap 4x£10 drills from argos surfice http://www.argos.co.uk/static/Produc...xt%3EDRILL.htm

those drills are fine and tbh i would go for a dual controller i don't think that the electonize are as good as a duall controller like the xxl or a sabertooth

a dual controller btw is a controller which will control both sides to your machine the electonize can only do one side so you will 2 of them and i personally find dual controllers much easier

Anyone know where I can get the Scorpion XXL in the UK and how much it cost as I cant seem to find one online, or alternativly am I better getting the Sabertooth Dual 25A for £92 at http://www.technobots.co.uk/acatalog...ersal_527.html

to be honest i don't think the saber tooth 25 A will handle , or not at least for very long. And i have heard that those are very easy to blow up. What esc is suitable really does depend on whether you need fine control or not.

No idea how finer control I need, have nothing to gauge it by, so kind need a good recommendation.

you have 2 options , proptrional and bang bang , bang bang is on / off , its etierh full speed ot nothing , in bth directions. Proportional control gives you an invinitely adjustable speed , so you can go round corners like you would in a car , not turning on the spot.

Prportional gives much finer control so is better for fast robots and robots with big budgets but tends to be a lot lot lot more expemsive than bang bang. Id recomend bang bang.

Bang-bang sound good to me, I assume u still have some steering options by running one side and not the other. What speed controller would i need to do this with the 4 motors?

Don't bother with bang bang. Proper proportional speed controllers are far superior and will give you a controllable machine. With a bang bang machine, you will be lucky to get it going in a straight line.

And for all those that have used them in the past, yes i know that they CAN work but thats not the point. I CAN open a tin of beans with a hammer and chisel but I'd much rather use a tin opener as it will do the job far better.

Proportional controllers such as the electronize, sabretooth, scorpion, sidewinder (a lot of s's in there) or any one of the marine controllers that are suitable don't necessarily have to cost a huge amount. Generally in the past I've built machines entirely from second hand parts from people on here.

How about two electronize FR30HX Controllers at £45 each or the XXL, it has already been hinted that the sabertooth wont handle it and i am currently looking into the others you suggested

go for an xl then get rick maas to upgrad eit to an xxl with extra cooling and protection - much easier to mount, and look after i can send you his emial if you want to talk to him

alex

Cools sound like a good idea, recon that would be able to handle the require ments? If so any idea where I can buy a XL from in the UK or do i need to order from america, also any idea how much tht upgrade costs? Thanks for the help

yeh 4 drills easy id say the upgrade for me was about £65 and you will need to buy from the us however rick sometimes holds finished models and you can buy one straight from him for the bigger amount

it is worth it though, he lives in the neatherlands so there is a slight postage cost but again worth it

i have pm ed you his email just ask him about it and he will help

alex

Ok think im going to buy my drills today, just before I do though it not worth upgrading to http://www.diy.com/diy/jsp/bq/nav.js...isSearch=false or http://www.argos.co.uk/static/Produc...LESS+DRILL.htm is it?

those 12v argos ones are fine the only difference i guessw ould be the life of the batteries, but 12volt will work fine plus you can over volt these motors by a few volts giving extra speed

plus the money you can save here might mean you can get the xl upgrade version

alex

ill second that. YOull have much more headroom for overvolting with the 12 V drills , and there cheaper.

Right well I bought my first two drills today (well when I say bought I had nectar card points saved up so actually free :) ). Ive emailed rick about the XXL and just waiting for him to message me back. Have also message grant to see if I can get some blue wheels. Just need to sort out a reciever and transmitter now.

Planet 5 !!!!!!
http://www.sussex-model-centre.co.uk/sh ... p?id=29064
Did you get the 12 V or 24 V drills in the end ?

Got 2 x 12v to start and im going get two more to go 4wd in the end, just got 2 to start with tho.

good good :). Have you thought about any weapons or what you want to build the thing out of ?

Weapon wise, I like the sound of an axe but im not sure on the particalities of this? Also I have fairly limited equipments so if anyone could suggest a good material to build from it would be a great help

I'd say HDPE or Nylon. HDPE is relatively low-cost and easy to work with as you can use basic hand tools to cut/drill it etc. It's also a great form of armour against spinning weapons as it absorbs some of the energy from the impact and, depending on the weapon type and speed, all you will be left with is a gouge in the armour. HDPE can also be used for bulkheads/structural supports but I wouldn't recommend it as it's quite a soft material so can deform under some of the stresses exerted.

Nylon is more expensive and stronger than HDPE but you can still work on it with hand tools. It can be used for armour but I'd recommend it more for structural components. It's heavier than HDPE too, but use it in something like a bolted bulkhead structure and you've got an incredibly strong chassis.

I've used both materials in two different robots and while the Nylon one cost more and took more effort to make, it's still going after two years. The HDPE had to be scrapped after two events. In its defence it took more of a beating from spinners and the Nylon one has steel armouring the back, but in general terms of internal strength, the HDPE one was not as good.

I'd have worded this more clearly but I'm off to a lecture shortly, so in summary I'd recommend Nylon for a chassis with HDPE for armour. If your budget is tighter go for HDPE for it all, but expect it to need more maintenance.

There are of course different options such as steel, aluminium etc but I've suggested the plastics as they are generally cheaper yet still endure the rigours of combat well.

http://www.directplasticsonline.co.uk is where you can find prices of Nylon (it's Nylon 6 you'd be after) and HDPE as well as other engineering plastics

Hi I have a Heavy weight robot The Saint that has used 12mm UHMWPE (similar to HDPE) for the wheels it has been axed by THZ and Thor with no problems at all and I now use 20mm UHMWPE for the top cover as it has proved to be more durable than 5mm steel armour and half the weight!
I love the stuff for making robots, if you look on the builders diaries for The Seraphim this robot is made entirely of HDPE and the stuff I quite often use is called RG1000 from direct plastics they are very good.
It is easy to cut (sharp wood saw) drill and with some heat you can bend it!
Have fun :mrgreen: :mrgreen:

My featherweight, Blitz, is made entirely out of 10mm HDPE. It has no additional structural components, but can take
all the beatings you like from any type of weapon I have encountered. It's cheap, easy to use,and if you use it well it
is super strong. You can also weld HDPE using a special nozzle for any heat gun and some HDPE filler rod.

Cool, HDPE seems the way to go then, apart from welding how easy is it to make good joints?

On the weapon front so i can start making a final design does anyone know of basic weapon guides? (Axe or flipper are probably my prefered choice but may be too complicated)

If you dont have access to a welder , which i doubt you do :shock: . I have never had problems with wood screws, never had one rip out of hdpe yet. For something a little stronger , cant go wrong with bolts and washers. Unfortunately hdpe cant be tapped so you will need to use nuts. To join 2 pieces togethor at a right angle use a bigger block of hdpe or use some andgle iron or box section as mounting blocks . Its really lovely stuff to work with :). Sounding good so far ! 8)

Got a message from Rick Mass back saying he can make the XXL for me :) but has never run 4 drill motors off it so not 100% sure it will be ok. He says:

I€™m not 100% sure that 1 XXL can power up 4 drill motors, because drill motors can draw high currents.

The biggest motor that we use in combination with an XXL in our robots are speed900 motors, they got the following specs:



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



Do you know what the drill motors are drawing at current in stall?

If you know that then we can see if 1 XXL is enough.

Anyone have any opinions of this for me?

If you do not need to undo the screws, HDPE can be tapped, but the thread may give way under a very heavy load.
As such, it is fine to tap and bolt hdpe as long as it is not holding on something like an overhanging panel that could be ripped off.

Thanks for all the help on that, whats the standard thickness to buy 10mm? and can anyone give me any advice on that speed controller so I can order it if its any good. Again many thanks

Looks like your only real option for an esc is 2 sabertooth 40 A. I hate them , but many people have used them for years with no problems. You will need 2 as they are only signle channel , but these will drive 2 drill motors each and should do what you need done :).

As for the hdpe , for structural parts id use very thick hdpe , or 10 mm nylon or similar , for the armour , unless you plan to put this up against a lot of spinners , 6 mm hdpe will be fine.