Richie: The £50, 3 week Featherweight

[daveimi]

"Can't complain for £3.50 each :P"

Jobsaguddun

[Rapidrory]

After one of the ESCs burnt out at the last event, Richie's been sat in my attic as a pile of parts. However with Whitwick coming up and it being half term, I decided I should probably start putting it back together.
I've fitted those Johnson 600 motors to the drive as that was a lot easier than fitting it to the lifter with the tools I currently have. They're a little close to the actuator, but not as close as the 550s used to be before the chassis upgrade so hopefully it's fine. I'm yet to test them out so don't know yet how they perform compared to 550's.. look good so far though.
To drive these, I've got my 400A heavyweight ESC in there atm, as the Johnsons draw a lot more current than the 550's, and I don't have any other ESC suitable to drive them. I'm using this as an excuse to test out the ESC to check it hasn't got any odd hardware/firmware bugs; It's a lot less scary to discover them in a Feather then it would be to find out in my heavy :L I'll have to find/ make a new ESC for Richie in the summer when this one moves to my heavy, but it'll do for now.
Also upgraded the wiring loom to be all XT60s (rather than a few PC Molex thrown in), and upgraded the battery to a 40C 2200 mAh, and swapped the fuse for a 60A one rather than two 30A fuses in parallel. Should all be a little less... flamey..

Unfortunately it would seem that I left the baseplate at home, so I've had to throw something together using a rather flimsy piece of chipboard I found... Not really ideal, but should hold; It's only really there to keep the dust out.

Here's a pic of the current setup:

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[daveimi]

You know your heavy esc? If it got damaged at an event do you think it would be possible to return for repair? Assuming you start selling them and everything?

[Rapidrory]

Considering the low volume that would be sold then that would probably be fine, though I'm still not planning on selling them just yet... If I get some home PCB manufacturing going on then I might look into it again..

[Rapidrory]

So, having completed an event with the Johnson 600 fitted instead of 550s, I have to say they're actually pretty good! My lifter died early in the day, meaning I had to resort to being just a rambot, so the drive got some thorough testing and I was very glad they were fitted; very noticeable increase in speed, I'd say around 50%, and I was able to push people around quite nicely, which is never normally something Richie can do. The motors were rather hot at the end of the two fights I lasted the full 3 minute for (you could almost burn your hand on them), but they're 9.6v motors overvolted to 12v so that wasn't too surprising. Both were still working fine at the end of the day though, and at £3.50 each, if one does burn out eventually, I'm not gonna be too upset :L

Fitting them to the drill gear boxes only required cutting a few mm off the end of the shaft, and then grinding a flat on it to fit the cog from the 550, all of which took about 5 mins with a dremel. After that it just screwed straight in to the drill gearbox as a 550 would. All in all took about 15 mins to fit each motor in the robot. Very worth while upgrade for the money and effort required.

In other news, the new Heavyweight speed controller I had fitted in Richie for testing worked flawlessly all day without getting even slightly warm, which means I can go ahead with building my heavyweight over Easter (This was hopefully the last event I do without a heavy).

As was mentioned earlier, Richie's lifter broke. This was courtesy of Battleaxe putting me on the floor flipper in just such a way that it hurled me into the steel wall of the arena. This bent the lifting forks, arm, and linkage, and the lifter drive circuitry also burnt out (Damn you Battleaxe! *shakes fist*). Managed to get things straight enough to be used, but with the lifter circuit gone and not enough time left to fix it, the lifter was out of action for the rest of the day. I'm planning a much neater solid state switching circuit that should be much more reliable.

[daveimi]

Glad you've got it sorted and think you should build a beetle

[Rapidrory]

I did; I had Bork in the Beetle competition at the weekend, and it even won a fight! :P


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Nah, I'm going to build a "serious" (or as near to serious as I get) beetle soon hopefully; got all the parts, just not all at at uni so'll have to wait until at least the easter holiday.

[daveimi]

Oh wow do you mean at the feather and heavy event you went to

[Rapidrory]

Yeah; the Beetle arena was there and we had a bit of a tournament in the break between the shows:

[Rapidrory]

Just finished off the new ESC for Richie: ~150A per motor at up to 40V (though the capacitor ratings limit it to 25v atm), with a total build cost of £7 for components.. Should be good enough for driving drill motors :P

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