An $800 robot...

Refering back to previous discussions: This is the $50 tank base with the $200 DDM added I've mentioned before.

Encoders are on output shafts. It has two PID loops, and odometry, steering, navigation. It will do "drive to a point" navigation. It has inputs for sonars, IR Rangers, bump switches. It has serial (115200), SPI (20MHz) and CAN (up to 1MHz) interfaces.

Maxstream RF links and Zigbee Bluetooth interfaces work great with it, if you want to get off-bot communications.

It's about to get GPS, shown, but not yet installed. (Although software is already proven in other vehicles.)

Of course, as you add things the price goes up (GPS, Blueetooth, sensors). Still, this is a rugged, large platform with plenty of open payload space. The electronics is tiny in comparison to any other feature on the tank.

But where's the drink holder???

-- Gordon

And what about the weaponry? He built a robot on a tank base and omitted the WEAPONRY?

Nice base - is NMI selling that for $50? Looks pretty nice especially if it includes mounted encoders. I'd like to use my own electronics of course, but the base is definitely something I'd be interested in. Do you offer that seperately?

-Brian

I think that is the tank WallMart was selling some time back.

The neat thing about the DMM is you just plug in, and go...

That was $150 wasn't it, not $50?

Sorry, I'm more inclined to use a single $99 MAVRIC-IIB for this and control the whole 'bot, not just the drive motors :-)

Not that the DDM is not nice - it looks very nice. I'm sure it is a fine product, just not my cup of tea.

I'm still be interested in that base for $50, though. Randy?

-Brian

Yes, this definately looks like the 1/6th scale M5 Stuart Tank (R/C) that Walmart is still selling for around $150.

They're a nice base and will haul a heavy payload, but the motors/treads are fairly loud and wake my wife. :(

I still have a spare for sometime later when I want to use it. And this time I'll keep the top with the (non-functional) gun.

-- D. Jay Newman

Yes these were originally $150.

W.E. Cole posted on the DPRG list that Walmart was clearing these tanks out at $50 this spring. He got two, and I asked him to get me one also. Many but not all the Walmarts followed suit. Also these tanks can be found on eBay sometimes going around $50 up.

So no, NMI isn't selling the tank base. Yes it is a nice one. Watch out for the motors. They measure around .6 ohms static at worst case, which means startup voltage will be ~10 - 20A. They're a little hard on H-bridges. Once rolling, they're around an Amp or two.

The DDM has two of our 5A Hbridges on it. Without heatsinks they're good for 2A. They work here by pulsing and going into protection on start up. The PWM rate keeps applying pulses of power until the tracks get moving.

There's a "pencil" launching cannon turret (spring launched, remote operations) which was taken off to get at the guts. The turret is motorized in azimuth at least. Don't think you can choose elevation. Some models shot those little soft BB balls, although I've never seen one of those in person.

Hmmm. I was thinking of something more along the lines of a frickin' LASER beam.

Actually, call me dense, but it hadn't yet occured to me the turret was the perfect "scanner" to mount cameras and range finders on. (Slaps forehead! Thwack!)

If I could replace that barrel with a .22 pistol, would that make you happier? Someone mentioned adding a machette to the front of a rover yesterday. I volunteered NOT to be there during that testing.

You'd lack tilt copntrol, though, and I imagine you might be able to more easily control the panning position with a standard hobby servo.

I get requests to weaponize REGIS all the time. As IF...

That's a great deal.

I'm currently working on an h-bridge that sounds perfect for this. I've tested at over 30 Amps continuous with a heat sink and they were asking for more. I have yet to actually push the limits to determine the upper bound. They will be for sale soon, but until then you can see 5 of them here, bottom photo, with a variety of heat sinks:

Click the photo for a larger shot.

-Brian

I would be interested to know if the base is available surplus anywhere....so is it?

As we all know, Walmart cleared them out and that source is long gone.

TMT

My local WalMart (State College, PA) still had them as of last week.

-- D. Jay Newman

Price?

I didn't ask and they didn't say. :)

-- D. Jay Newman

I checked today and found that my local Walmart was selling the suckers for full price ($148).

I saw they had at least 5.

-- D. Jay Newman