4WD

Hello, I am considering making a 4WD for my second robot. I am a bit confused about this though. Do I need 4-channel radio gear, or do I just run 2 motors through 1 speedo?

Unless you have some exotic drive train then you will only need two channels to drive.

You can run two motors off of one speed controller but I would check if the controller can take the extra load of another motor so you don't break it.

Thanks. Are there any speedos I should avoid for a feather full body hammer If I do that?

Welcome to the forum first :)

As a general rule anything that's designed for remote control cars and is rated at aburdly high levels should be avoided, they'll just blow up. The Electronize controllers have a good reputation although you need at least two of them (one per side), while the Sabertooth 2x25A controls both sides in one unit and is quite good in my experience (I wouldn't use it on anything more powerful than drill motors though)

Everyone has their own recommendation though, based on their own experience, so it's best to ask :)

Thanks Joey. :)
Can anybody who had particularly good experiences with a 4WD feather please reccomend me a speedo?

Edit: While I'm at it, I've got two more questions:
1) Can anybody recomend a 2-channel radio system?
2) Do feathers need gearboxes?

most of us now use a radio system called spektrum these radios have some really good features and are as cheap as some fm stuff

they only come in a minimum of 3 channels, but those are pricey there are some 5 channel ones cheaper (would you believe)

you will need some kind of reduction gearbox on any motor

if you just want to practice and see if this is for you gor the cheaper option of 4 drill motors these have gear boxes attached you see

decide upon your motors then the contrller to go with them

alex

Would you reccomend the spektrum for drills then?

Edit: Sorry for so many questions, I'm just so eager.

1) Would you reccomend the mtronics eco 27 speed controllers?
2) Where can I buy a safety link + LED?

having good 4wd experiance id say, for your first bot, make a nice rectangular base, then get 4 drills from argos (£10 each or so) and mount themto your base. get some blue wheels from james or grant cooper and they just screw onto the drill shaft, then wire the two left motors up to each other, you should have two wires left over, do the same to the other side, buy a speed controller, id recomend tom wilkinsons speed controllers as they are very good and quite cheap, he isnt a big brand though so if he dosent have what you want the electronize speedos ( a different word for speedo is esc btw) ut you wil need 2, wire the wires from the drills into their respective esc/s (one es for each drill if its electronize, one esc for both if its a dual esc) and then plug the other wires coming from te esc into the reiciever. there should be a battery slot coming from the esc, plug your battery into there, well thats my area of knowledge :P ask around for other tips, we dont bite....mostly :P

Thanks Jack, just one thing, where do I get the blue wheels? I know you said Grant Cooper, but is he a member here or something?

yes he is
he and his brother james cooper run the full combat featherweight show robo challenge :)

james:

memberlist.php?mode=viewprofile&u=881

grant:

<a class=postlink-local href=http://www.fightingrobots.co.uk/foru...r /> <br /> oh

You asked:

1) Would you reccomend the mtronics eco 27 speed controllers?

No. With a 4 wheel drive machine you would need 4 of them, one per motor, because they can't handle much current. Even with 4 you might well overload them and for the price of 4 you could get more capable speed controllers. Also, they only go up to 12 volts so you can't over volt your motors which is a good way of getting extra speed and power. I used them once on a 2WD 8 kg feather and they worked for a while but were just not up to it.

2) Where can I buy a safety link + LED?

You can get a wide choice of LED's at Maplin. You can buy a link from Technobots or you can make one yourself. For feather links I use a loop of wire terminated in male bullet connectors with female ones inside the robot. Cost is about 10p if you have a pack of each kind on hand and you should because they are very useful for joining up things inside your bot.

Caome to an event and have a look at people's links - there are lots of ways to do it. I've sen one made out of a 13 amp mains plug.

So you'll be at Reading? Will you be there on sunday?

Edit: Thanks John. That question was aimed at Jack.

unfortunetly not, however, my friend dave weston will show you his robots and im sure other people will show you theirs if you ask nicey :D

yeh the spektrum can be used with many different things including drill motors

http://robotbirds.com/catalog/product_i ... ts_id=1540

thats a dx6 with 6 channels i have 2 they are great and have decreased in price, trust me you will be glad of more channels you can also charge this one with the a wall charger and it has a good build qulaity feel

hope this helps
alex

true for above but also try and get a BR6000 Receiver: not an AR6000 Receiver:

i did see a post about the 2.4 gig system for £30 (but has very limited bits no mixing etc but £30 ) :)

hi
actualy i will be at reading on the sunday now :P so yeah il see you there

Hello again. Thanks everybody for the responses.
I have three questions.
1) Can anybody reccomend a specific speedo for 4wd's?
2) Can anybody explain about the saftey links in more detail?

I am happy to wait until Reading for those to be answered.

Also, a more general thing,
3) If I was to go and only do a 2WD robot, would I need to fit an axel at the front or just mount the wheels on?

Hi,

Try and find me at reading and I'll show you the insides of Whirlpool (our 4WD pusher).

We will be there as well, so get Will to bring you over and have a gander inside Stagefright, to see how not to do it. :rofl:

hey guess what?
im gonna be there both days now :P so come take a look at any of my robots whenever, just ask me and il talk anyone through it, oh and that goes to everyone not just Helloher

Quote:

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I've seen one made out of a 13 amp mains plug.

---

That was fun :)
Used to get some odd looks for having a run-of-the-mill household plug sticking out the back of my robot. It did the job but isn't the most reliable method as a large ramming impact can knock it out slightly and disrupt the power flow.
However at the time I was extremely skint (not much has changed right now :() so it was a low-cost solution as I scavenged the parts from the tubs of electrical bits and bobs we had in our cupboard

What about the Type FR30HX Elextronize Controllers? Would they be suitable?

Also, somebody said you can buy Safety links from Technobots, but I've looked and can't find any.

yeh those controllers would be fine again you would need 2

make your own link with the samller deans connectors (most people do this)

http://www.technobots.co.uk/acatalog/Si ... ctors.html

or like me you could use these called denas connectors less hassle and can be more reliable IMO

http://cgi.ebay.co.uk/10-Pairs-Deans-St ... 518d692362

alex

i know this has nothing to do with this topic but will anyone here be a wigan in december?

well, i have been known too use tin foil...but dont just dont :P

i personaly use the anderson connecters, just a personal prefrence but deans work just as well, i just think that if your robot is spazing around in the arena with a 4kg disk, if i were the arena marchal i would want the biggest link possible :P

if you want even more low-tech option go down to your local maplin and buy a couple of tamiya connectors, simple and cheap, and the good news is that its maplin! so you can get some LEDS (mine where £1.50 per ba, i got 2 packs of 20 :) ) and some solder etc etc, also, i was quite supprised to find the mfa motors there, they were £20 and i think they would work well.

you could also get some dpdt switches (double pole double throw) and some servos and make a low cost esc as seen in rexs robot challenge. but that is a bit off topic :P but what im doing atm

@everyone: could i use the dpdt switch style esc in a 4wd system?

jack

yes :proud:

awsome :proud: , il do some testing :mrgreen:

as the 4 wd thing goes , ill be at reading on sunday and ive recetnly finishes a 4 wd drive bot using 2 drill motors and ten quids worth of chain and sprockets from t bots