Cheap robot bases

Tue, 17/06/2008 - 6:36am — kymhorsell

I finally got off my bum and took some vid of the 2 RC trucks I'm about to covert into robot bases for one of my paying assignments.

While converting RC trucks to robots is pretty common, it's usual to take a $us300++ nitro model and do the chopping. Or -- if possible -- find a complete chassis kit for such a beast.

But being a bit on the cheap side, I found these 2 70 usd 1:4 scale trucks in my Googlings, and couldn't resist getting samples to see what they amounted to.

The larger beast is a H2 hummer. I had to import this from Shankers, since no-one else seemed to have any available. If you look around, you'll find a $200 usd model of the same thing with MP3 player installed; I want for this "warts and all" model that basically is just a big truck. :)

The other model is a Ford with working pimped-out sound system in the tray. I like to keep that switched off -- it's lound.

While both models performed pretty much as claimed by the makers, it turned out the hummer is the poor cousin of the pair. The radio controls only allow full-speed fwd/back, and the steering is only +- 10 deg. All in all, a bit hard to control.

The hummer also came "pre broken", with the rear suspension never properly installed. And it's hard to fix as is, without dismantling everything to get at the inside of the base.

The Ford has a plastic 3-sp gearbox to allow a bit more precise radio control. All in all, it's a better-made unit. You can tell from the rubber tyres and branded battery in the battery compartment. (The hummer has a home-made pack that looks a bit like a milk crate).

It all seems a bit of a pity to pull the tops off these things and start drilling into the chassis'. I'll loose all those automatically opening doors, moving guns and rocket launchers, and lifelike anti-theft devices (in the Ford only). :)

But the idea is to install a small processor and "naviagtion module" and a wifi link to have these things navigate around the block, looking for trouble. And making it, if none can be found. :)

video:

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Fri, 20/06/2008 - 4:09am — robotman

Hi Kym How much weight can

Hi Kym

How much weight can you stack on top of these bases? ie. At what limit does the suspension become overloaded?

Thanks
Rod

Fri, 20/06/2008 - 5:23am — kymhorsell

Supposedly 50 kg pushes the

Supposedly 50 kg pushes the springs as far as they are supposed to go on flat surfaces.

But I won't push my luck and I'll only have around 15 kg of stuff, incl the battery bank.

Each truck is around ~ 1m long x 50 cm x 50 cm high and weighs around 6 kg as it comes, and from my preliminary unbolting it seems around 3 kg of that is the plastic top and the various speakers (2,3 and 4-inch in various cases).

Before I completely wreck things I think I'll take some vid of what they do "out of the box".

If they spent as much time planning out how to make the toys as flexible as possible instead of loading them down with laser pointers, sound systems, opening doors, and central-locking systems, I wouldn't probably dare take a screwdriver to them. :)

But they certainly have the 60-70 usd worth of parts in them I paid for, incl the 8-channel 27 MHz radio (2-way comms in the case of the Ford, since you need to see the scale kph on your radio console as you push down the pedal :), 4 12V DC motors, a few plastic gear chains, and a couple of servos each.

Fri, 20/06/2008 - 5:43am — robotman

I've been looking at the

I've been looking at the 1:4 scale Traxxas 4WD:

http://www.rchobbies.com.au/store/product_info.php?cPath=24_39&products_id=39&osCsid=d8f403bbccf4f8635bb952d372892a00

and although expensive (and brand new!) it seems on-par with the units you purchased and they probably have the same abilities and limitations.

But, I'm really thinking though that AUD$600 is *way too much* to spend and then hack... I should take a better look at the FORD:

http://www.wowzzers.com/product_info.php?products_id=304

or the HUMMER:

http://www.hobbytron.com/14ScaleRTRElectricRCMilitaryHummer.html

I wonder what the postage will cost?

Rod

Fri, 20/06/2008 - 6:16am — kym (not verified)

I had a look at the Ford and

I had a look at the Ford and Hummer you pointed out. The Ford is exactly the same thing I bought, but for twice the USD price. I also bought mine from LA.

The Hummer is a different and apparently better model than the one I got from Shaghai. It's more like the Ford, with a 3sp gearbox. The H2 I snaffled is 100% fwd, 100% back or 100% stop. :)

As I said, both things cost 60-70 usd, so you shouldn't need to pay more. Again, check with ebay. You will probably see (e.g.) the Ford truck about a dozen times, at 2 prices, from the same store. I don't get it, but that's how it works on ebay these days...

Fri, 20/06/2008 - 6:07am — kym (not verified)

Maybe a good choice. A lot

Maybe a good choice. A lot of Traxxas stuff on ebay at the moment. You could pick up a shop-worn 1:4 for $100 usd, esp since you don't really want the nitro engine... Or *do* you. ;)

Fri, 20/06/2008 - 6:01am — kym (not verified)

Postage on both the 1:4

Postage on both the 1:4 things was around $100 usd +- 10 usd. And they came pretty fast -- within 1 wk. C.f. a 4C cell battery box that took 3 weeks from HK. :}

I know how you feel about hacking. Sometimes I get something -- e.g. I've been looking at sonar tape measures (range >30m), fish-finders with NMEA output, and laser range finders (range upto 1 km) -- and it's hard to take an axe to them or even snip a sensor off the wiring.

Doubly hard if you pay good money for it.

Thu, 19/06/2008 - 3:08am — Dingo_aus