[Side note: if images don't load, see
https://rctruckandconstruction.com/s...7&postcount=16 ]
Had more free time lately, so I figured I'd liven things up a bit here and do up some picture threads of my builds vs actually building. Might give ideas to the next guy, might stimulate discussion for good ideas to change up this build or for the next one.
Bit of background: I've been building things of many sizes for years, ranging from scale models to RC vehicles to a 1.5ton ride-on backhoe with working hydraulics. I hate hydraulic fluid.
My usual builds are like half-fab or kit, half-3D print, and heavy on Arduinos and moving parts. See my
HEMTT (PLS) @
https://rctruckandconstruction.com/s...d.php?p=170548
Forklift @
https://rctruckandconstruction.com/s...d.php?p=170566
M1 Abrams @
https://rctruckandconstruction.com/s...ad.php?t=13837
For a little variety, though, this one is somebody else's design, and most all 3D printed. And has no Arduinos and few LED's (but does have fun moving parts.)
The original design is from
http://makitpro.com/index.php/openrc-tractor/
Some bits of this particular build are "remixes", wherein somebody else has taken the original design, and made new parts that fit the original kit. I wanted a bit more modern style, so I used parts from
https://www.myminifactory.com/object...tractor-118258
and then did a few of my own (see below.)
It's a BUNCH of 3D printed parts, like the original even calls for printed tires (either out of hard plastic or flexible material, if you're equipped to do so)
Then the steering linkage, and some of the drive bits are metal, off-the-shelf threaded rod, rod ends, bearings, all Chinesium you get from Fleabay or AliExpress or Amazon. The motor and electronics are all regular RC stuff too, just small ones as you'd use on eg a Bruder conversion.
In the interest of simplicity (and because there is NO room under the hood) this one is 100% Arduino free =))
I opted for rubber tires instead of printing them, as I've not had a lot of experience with flexible filament and I like the realism of real tires. The rears are monster truck style, to get an appropriate agricultural-style tread, and the fronts are airplane tires so they're nice and skinny. In both cases the wheels are printed. The fronts actually came on wheels that I had to Dremel off, but they were white. It was easier to print a set to color match than to try and paint the white.
Under the hood, the RX (here, bottom left) goes up front between the headlights. The breadboard there is resistors for the head- and marker LED's (see below). Just takes power from the RX and then has the series current limiting resistors for the LED's.
The bronze-colored heatsink is the small ESC. Below it is a 9g servo for steering. The blue circuit board center bottom is the switch for the light bar (see below). The rest of the underhood space is taken up by the battery and the excessive, poorly run wiring
Hard to see, but the main drive gearmotor is center, below the battery connector. The two switches forward of the steering wheel are leftovers from conversions on my TX's; the long-lever one is the power switch and the other just looks pretty.
The monster truck tires in the rear were so wide that I had to CAD up wider fenders, which gave me the opportunity to add marker lights. They don't blink for turns (again, no Arduino), but add a bit of realism and fun.
Similarly, the headlights are on full-time, but the light bar and beacon up top are on a little switched MOSFET thing run off an auxiliary TX channel.
Because I'd done custom fenders, I had to CAD and print a custom ROPS, so I made it fold
which allows it to just BARELY fit into my conexes. It took careful adjusting of the rear wheel backspacing to allow this. There's like 2mm on each side of the tractor in the conex, and similar clearance inside the fenders between the tire and the tractor body.
One really clever thing on this -- and again, I can't take credit as it's not my design -- is that it's set up for implements in the rear. There's a pair of 9g servos under the seat, though you wouldn't know unless you were looking for them. These drive a pair of arms to lift the implement; there's also a center fixed arm, very much in the style of the 1:1 tractor hitches.
The one tricky thing is that since the servos face opposite each other, you need a servo reverser for one side along with a Y-cable, and it's hard to fit all of that into the tiny space. It's also hairy to get the servo horns aligned. I learned to do it with the fenders off and then glue the snot out of the printed bits that go onto the arms. Properly set up, a dial on the TX adjusts the lift servos up and down so the implement raises and lowers.
There's a number of different implements, some passive, like a rake, and some motorized, like the seed spreader you see above. It has a tiny little gear motor in the center driving the spiral fluted spread. It uses a similarly tiny ESC for that motor (the circuit board floating above the left lift arm that I haven't zip-tied down yet.) Because I could only fit the 6-channel RX in there, I ended up using the left stick on the TX to control the ESC for the spreader.
and that's as it sits with the spreader attached and hood snapped into place.