Torrent's build diary - a dream coming true!

[MudnuK]

Hello all! I'm a little nervous posting a thread about building a robot, since it has always been a childhood dream of mine. It's hard to imagine it actually happening! Anyway, I feel I should do a short introduction for myself before I do anything, if you don't mind.
I'm Miles, and I've been a huge fan of robotic combat since I was three years old. I'm now fifteen and have discovered featherweights quite recently so I thought I could try to build one. However, I have almost no experience of hands on mechanics or electronics, doing two years of D&T before dropping it at GCSE (and then I decided mechanics were really interesting and I should build a robot). My parents know as little as I do, but I at least have access to teachers and all the basic equipment. What I have done is followed this forum very closely for about three months, and I've picked up quite a lot, enough at least to start designing.
The robot I have in mind will have to be on a budget, but I'd like to have some sort of flipper with a twist. I'll get on to that. First priority is getting a moving robot together. I have limited knowledge, experience and cash, but I think I have a good grasp on tactics, and I'm sure I have enough of an interest, to build myself a robot which I'll be calling Torrent (the name doesn't seem to be taken). I'm learning fast, but feel free to treat me like an idiot, because I know very little about electronics and mechanics. I'll put together a simple parts list of all the important bits which look like they could work, but in the meantime, I'm going to GSL tomorrow, and again on Sunday, and it would mean a lot to me if I could have a talk to one of you about building a fighting machine, though I know I can't go backstage.
Anyway, once again, hello Roboteers! My seven-year-old self would be amazed that I'm saying that!

[harry hills]

My seven-year-old self would be amazed that I'm saying that!

Know the feeling! Welcome to the forum, and good luck with your build.

[MudnuK]

Went to my first live event yesterday; GSL. Wish I could've made the second round, but I'll be there again tomorrow. For those who saw me, I was the over-exited guy in the black coat walking up and down the pits between fights sessions. Nice to see some of the robots/roboteers, even if I didn't really meet anyone, though I had a short talk to James and 'typhoon-driver'. I was very impressed; it all looked very professional and I think everyone who saw it liked it. Might bring the camera along tomorrow and do some filming and photographing.

[daveimi]

I went to York Railway Museum and chatted to the Big Nipper guys and ear wigged on Mighty Mouse teams convo. It was awesome.

[firefly1]

I met the guy (can't remember his name) who helped build and typhoon2 at the Big Bang Fair at the exel centre, very interesting

[MudnuK]

Had a great time at the gadget show. Especially nice to be let into the pits by Dave (RazerDave) and have a good up close look at the robots, as well as meet a lot of you guys and be given helpful tips.
Congrats to Michael for finally winning and commiserations to everyone else. It was great to watch and I really feel like I'm part of the community now!
I'll put my photos and videos up on here sometime soon. In the mean time, nice to meet you lot

[evristow]

Mudnuk,


We all been on the stage where we want to build a robot, but don't know were to start. hence I think the below link will help you a lot:

RioBotz Combat Robot Tutorial

Just pay attention to the fact that FRA and RFL rules differ in some aspects.


Regards,

Eduardo

[MudnuK]

Thanks Eduardo, it'll make nice light reading!
I know I said I'd get a parts list together. I made one a little while ago, but haven't been able to get to it. Now that I can, I think I need to have another look at all the sizes, weights ect. The basic idea will be to build a wedge robot which can be easily upgraded to the robot I want it to be. That means designing it to have an electric flipping weapon, and then taking that weapon away and making it invertible. The problem is, with the shape I want to use, it'll probably rear up when I accelerate when the robot's upside-down. I'll figure something out though. It'll hopefully look something like Satanix, but with a much larger single front wedge and without the spikes. Not a great description, but I'll try to draw something (I can't stand SketchUp!)
Finally, I said I'd upload the images and videos soon. Well, I now don't have access to the images, and for the videos I tried some 'dynamic' filming (so everything's a little shaky) and, having an 'audience-eye view', the black bars inn the joints in the arena get in the way sometimes, and there weren't many in the first place, because I forgot to charge the batteries the day before. I'll still upload a couple, but there's little point in uploading them all.
In other news, I've started taking an old RC toy truck to bits. I know the motors will almost certainly not be powerful enough when I finally break them out, and the 9.6v NiMh battery pack probably doesn't work anymore (it's an old, little used truck) or won't be enough, so I'm doing this for practice more than anything.
Quite a long post full of not-very-interesting bits, but things will pick up soon if I get my arse into gear.

[MudnuK]

Right. At the moment this isn't really a build diary, it's just a few ideas being scattered around, so now I need to figure out just what I'm doing.
I said I'd make a parts list, but to be honest I'm still not sure what I'm looking for. I have a list of ideas but I don't know which ones are good ideas and which ones aren't. Some straight-up advice would be fantastically useful! Look at Torrent's 'build' diary for the kind of thing I'm thinking of, and I'd like it to be reasonably cheap.
I know the basics of what I need i.e. motors, an esc, Tx and Rx and so on, but which ones?

First, motors. I'm looking at the RoboChallenge ones, and have been told they'll do for a simple pushbot. I'm assuming two will be enough? Or maybe not? You can tell how clueless I really am!

Second, ESCs. BotBitz TZ85a ones seem highly commended, but I've heard good things elsewhere. What am I really looking for?

Third, batteries. LiPos are the preferred choice among most of you. I've heard somewhere around 6 or 8S is best, and 3000MaH is what I need.

Fourth, Tx and Rx. I think 3-channel would be preferred, since I will put a weapon on eventually. Other than that, I hardly know anything.

Fifth, armor, bulkheads etc. I'm definitely thinking HDPE, since it's easy to cut, and I can do it with a simple saw. I understand it needs to be quite thick. I'm trying to remember how thick the armour was on the machines at the champs... something like 15 to 20mm bulkheads/chassis with thinner armour, like 10mm?

I'm sorry for how little I know. Despite reading through the build diaries, somehow only a little seems to stick. Once I have the basics down, I'll stop asking stupid questions!

[harry hills]

Quit being so hard on yourself, you're making more sense than other newbies have done.
Robochallange motors are just drills pre modified, so they will work, but if i was you, i'd buy, strip and modify the drills yourself. you'll learn a fair bit about your drivetrain that way and its not at all difficult with things like Ellis's guide on youtube.
Two drill motors won't give you much pushing power, but will be more than okay to get yourself going, if your budget can stretch, I say go for four.
I haven't used the botbitz myself, but they seem pretty bulletproof. Tormenta 2 and 720 are both quite powerfully driven machines and they cope fine. Someone with first hand experiences can tell you.
for 12v drills, 6cell will cook them, 3, 4 or 5 cell will be more useable although you may burn out motors on 5cell. I'll leave lipos to someone else, but you will need to look at the discharge ratings etc not just the capacity . For a 2 or 4 drill machine you won't need uber amounts of power.
Go and buy a DX5e, can't really go wrong. Or a DX6i if you have large amounts to spend. I personally run the DX5e, no problems and really simple to use.
HDPE is fine, although some may scoff at it. i had 20mm armor plates and nothing got through those at the champs. Facing some robots i'd be a little wary of using 10mm, 20mm bulkheads and 15mm armor sounds good to me. Remember, if you are planning to use lipos you will need a metal base plate.

These are my thoughts anyway. Good luck.

[SamO]

For Endeavour we used 15mm HDPE for everything, bulkheads and all.

Seemed to stand up very well against spinners

[MudnuK]

Thanks for feedback. I will certainly go for HDPE, and will make it around 15mm, perhaps a little bit thicker in places. I'd say I can do four motors at a stretch, bearing in mind I'll need to gear all of them, mount them and buy the extra wheels, but that's not too much expense. I'm think I'm right in saying I still only the two speed controllers.
Speaking of which, I've been looking at a couple more guides but without knowing the amperage needed I can't figure out which battery or esc I need.To find out the c rating needed I need to know the capacity, and for the capacity I need to know the amperage.
You seem very sure with the DX5e, so I will probably go with that.
Any more recommendations or views would be helpful

[plargen]

with the lipos you times the amps by the c rating to get the current eg a 2200mah with a 30c you would do 2.2X30 to get 60a

are you going to go for drill motors or something else

[MudnuK]

Yes I will use drill motors

[plargen]

ok well im using a turnigy nano tech 4s 2.2a 35c cont 70c burst so about 157a peak and thats running the 4 drills in night fury the motors get quite warm and the battery only gets warm if im doing alot of pushing for the full 3 min.