Torrent's build diary - a dream coming true!

[MudnuK]

Diagonal 2wd might not work for my design actually. I'll just have the wheels poking through the angled sides.

Does this look like a suitable battery for Torrent?
http://www.hobbyking.com/hobbyking/s...dProduct=34271

[Porker]

I've got 2.2 amp-hour, 3S batteries with a 25 to 35 C discharge, so that should be around 55 amps at 25 C per battery.

The (4S)battery which you found can produce around 53 amps at 20 C.

[plargen]

it should be ok for for running 2 motors just make sure u have a fuse rated at half the peak amp

i use these batteries http://www.hobbyking.com/hobbyking/s...%20lipo%20nano

they seem to do the job quite nicely

[MudnuK]

So, after three months of almost no real progress, time for a parts list. Please point out any flaws or recommend any good, cheaper alternatives:

Motors: 2x Argos 12V drill motors
Battery pack: Turnigy 2650mah 4S LiPo with 20C constant and 30C burst
Speed Controllers: 2x BotBitz TZ85a
Tx and RX: Spectrum DX5e (but also curious about trigger transmitters)
Armour: 10mm HDPE shell with 12mm HDPE bulkheads
Other: 125mm diameter RoboChallenge blue wheels
2 or 3mm aluminium to protect the battery

Sound reasonable?

[Max]

I don't think robochallenge do 125mm wheels with nut inserts which you need to screw it onto your drill motor- better to go with 100mm wheels or else make your own.

[TeamPsyclone]

They take ages to come, too. I know they're busy, but it's a pain. You can make custom mounts (Bar of hdpe, screwed onto motor shaft), or use nut inserts for whatever wheels, I'm using stabilizer wheels atm.

[MudnuK]

No, RC don't do 125mm wheels with the inserts, but it can't bee to difficult to put them in myself? And anyway, as Josh said, I can make my own if need be. I have all the time in the world though (it's taken me long enough to decide what parts I'm having), so the wait shouldn't be a problem.

[plargen]

Tx and RX: Spectrum DX5e (but also curious about trigger transmitters)

i use the trigger tx on both my present robots (DX3e and a losi) the main benefit i found is that you can tune the steering to get a strait line and slow the steering down so you don't over steer, but i only really need it as they do about 8-9mph

[RogueTwoRobots]

No, RC don't do 125mm wheels with the inserts, but it can't bee to difficult to put them in myself?

If I'm right, the reason RC don't do the 125mm blue/red wheels with nut inserts is because the bore of the plain wheel is 15mm, which is too large to get a nut pressed in and 'latched' onto the plastic; most likely the nut would work itself loose and the wheel would come off. When I've bought 125mm wheels from them in the past, they've been a different kind - black, with a 12mm bore, which is more suitable - but the wheel material isn't great, it's quite shiny and hard and doesn't hold up against the blue/red competition wheels.

The best way to get 125mm wheels with nut inserts will be to make them yourself. You could just cut circles of HDPE and melt a nut into the middle, but since HDPE is quite soft, it might not be the sturdiest connection. I've got a strip of steel with the nut welded on the middle, and a couple of bolts at the ends to bolt the wheels on to (similar to the method Josh described) and this seems to work well. Also means you can bolt on different diameters of wheels if you feel you need more speed or torque.

[MudnuK]

Sorry I've not been active for a while - nerves crept up on me again. My lack of experience really is a pain, especially as I hate to seem ignorant, even though I know you guys will be supportive. Still, I'm determined to prove that you can go from nothing and end up with a featherweight. Yes, I probably should build an antweight first, but they just aren't quite the same (no offense to antweight builders). I've finally taken the sensible choice to go for some cheaper parts, as I simply couldn't afford making a robot just to have it break. Therefore I'm switching to some more budget parts.

I'm going to switch to the far cheaper ETRONIX EX4G Tx and Rx, as I don't need a fifth weapon channel yet. I'm also looking for cheaper speed controllers. I always prefer to turn to experience rather than research (not that I haven't had a look), so any suggestions? Thanks in advance.

[MudnuK]

Ummm... cheaper speed controllers? Please?

[Max]

There are tons of threads talking about the merits of each type of speed controller, just have a look through the featherweight section. Botbitz are probably the best value for money/cheapest esc other than the problematic eBay ones.

[plargen]

I've managed to buy some of the problem 1s off ebay recently just properly tested them and the stop when shifting from full forward to revers, im gonna dismantle them and see if there are any component differences between the previous 1s i bought that work and the newer version

ive also ordered some more from a different suppler to test out probably wont see them till the end of the month but i can post up the link if they work

[Eventorizon]

I know you are trying to do everything on a budget but their are certain things you can see as an investment or that are not worth going cheap on, the Transmitter and Receiver is one and ESC's are another.

A good Transmitter is something you can use for years and on many, many machines. Thanks to DSM2 you could own an antweight, a beetleweight and a feather and since you will never drive them all at the same time use 1 Transmitter. So the cost can be split over 3 machines. But the key point is that you will be spending £250+ usually more on the machine and if your £25 transmitter fails then that could easily be your £250 gone in one swoop. A DX5 is about £70-90 and will last years if looked after properly.

ESC's can make or break a machine as it is the single part that will have the greatest effect over how your machine drives. A good ESC can take a mediocre machine up to something that can out drive and manoeuvre some of the big players in the game. The hacked TZ85A transformed Conker 2 and Made driving Binky so much easier. Ellis was raving about the improvement to Tormenta 2 at GSL. Use the right fuse and ESC's can last you several machines (My TZ85A's went briefly in Conker 1, Did GSL in Conker 3 and are now going into C3) if set up right and make your life a whole lot easier when it comes to driving under combat conditions.

[MudnuK]

Over a year. It's been over a year since I last made any effort towards even thinking about building a robot. Well, I want to say I haven't ever given in completely. I've kept up to date on YouTube and read a few posts on here. Nothing much, but I haven't completely given up.

Anyway, yes I'm still here. Yes, I still want to build a robot. No, I haven't really done anything yet. I've made excuses to myself already and now I'm more determined than ever. I've bought a crappy, cheap soldering iron which won't last me but it works at least and, as ever, I have a few questions:

If my battery is rated 2650mAh with a c-rating of 20-30 than my max current amp draw is 79.5A (i.e. 2.65A x 30), right? But, according to razerdave from a year ago, I shouldn't be pulling anything like that. Apparently I need a fuse rated for around half the max amp draw, right? So, around 40 or 50 amps?

And then, what about wire? It's a fundamental part of a robot which nobody seems to mention on here. What sort of wire do I need that can handle 40 to 50 amps? I've gone a bought some crappy 7-0.2mm wire from Maplin and I've realised that's not going to cut the mustard. The website says that wire can only take 1.4 amps. Am I going to need some pretty heavy duty wire, like the ones coming out of my tz85as? Where can I get some?

One final thing - what's the name of that red plug that most people use for their removable link?

I've come to realise that it's better to ask stupid questions than to sit like a lemon because you don't know the answers and that the value of my equipment is really in the experience, even if it's just the experience of building something and wiring it wrong, rather than in the equipment itself. I'm now willing to build a robot or break stuff trying.