1:10 10x10 "HEMTT" (actually M1074 PLS w/ M1076 trailer)

[frizzen]

Great looking truck!!!

The loading system and crane look like they'll work really well. Doesn't look like any fun designing those...

Oh no, another of those crazy Fiero owners?

[dremu]

Originally Posted by frizzen

Great looking truck!!!

The loading system and crane look like they'll work really well. Doesn't look like any fun designing those...

Oh no, another of those crazy Fiero owners?

"Crazy Fiero owner" is redundant, btw

The problem I have with the load/unload -- besides, yeah, the weeks of designing them and having to recall high school trigonometry! -- is actually doing it. It's just two dials on the TX, but for some reason I can only do it while looking from the left. If I'm on the right-hand side of the truck the dials are "wrong" in my head.

I've found it best to move the hook up as the A-frame goes up, then down while still moving the frame up, then the hook goes back up again, to get a nice smooth movement without tipping the load at too great an angle. Harder than it looks, and gives you respect for the folks who do this on 1:1's.

I took some video early on, with the parts in place but before paint and with crazy messy wiring:

https://youtu.be/7gGnfUmpqAM
https://youtu.be/oZ4iLoMdgig

You can see sometimes I move the hook up when I meant to move it down; when the arm is down, twisting the hook dial one way moves the hook "up", but once the arm is up, twisting the hook dial that same direction moves the hook "down". I think even if I changed the dials out for momentary switches I'd have the same problem, as for some parts of the arc pushing the switch "up" would move the hook "down." Ow, my head

After the truck was finished I did some more videos. Here's picking up the flat rack, with the Cross RC truck tied down:

https://youtu.be/G1gigDKLBgU

and driving around loaded

https://youtu.be/tIGJTuGSd-E

eagle-eyed viewers may notice one of the front marker and turn sets is munged in this video.

Unloading the flatrack with the conex on it

https://youtu.be/3_SnaMT9GGc

The outrigger feet in the back aren't just for looks. Even with the pool noodle tire foams, the weight and force of loading anything really pushes the back end down.

Sorry for the crappy video, apparently it was dark in the garage. Outside looks a little better

https://youtu.be/Vl4-64sQ4DQ

And my dad having fun (and some trouble with steering)

https://youtu.be/EMaO3L1g0b0

Leftover gravel, river rock and roof shingles from various house projects can become a playground with a little effort. The bridge is a broken-down pallet (remember Bridge Over The River Kwai? This is Bridge Over The Railroad Tie.)

[frizzen]

Originally Posted by dremu

"Crazy Fiero owner" is redundant, btw

Nope, don't know anything about that.


I'm not suprised running the loading arm makes a lot more sence one direction, i've learned that my dragline crane is easier to explain and run from the Right side of machine.

Since you've got the basic Conex already, modding one into a CHU should be a pretty simple additional load to print.

Glad the machine passed the cat-scans.
You build really fast!

[dremu]

Originally Posted by frizzen

Nope, don't know anything about that.

I'm not suprised running the loading arm makes a lot more sence one direction, i've learned that my dragline crane is easier to explain and run from the Right side of machine.

Since you've got the basic Conex already, modding one into a CHU should be a pretty simple additional load to print.

Glad the machine passed the cat-scans.
You build really fast!

Sweet mini-me Fiero! At least you don't have the Indy go-kart. Or do you? There's those guys on Pennock's with three or more sizes of Fieros. Which is almost as bad as having multiple full-size ones. (I mean, they're fun, but keeping up on my one is enough for me!)

I looked at the CHU, but given the weight of the conex and its leverage, I'm not convinced I could make the CHU work in plastic. Seems like it would either snap the corner twistlocks off the conex, or just break the CHU. That's why I stuck with the flatrack and let gravity do the work.

Since then I've actually also built a reach stacker for the conexes (conexi?), but it's a combination of metal rods on roller bearings with printed bits, so as to carry the weight.

Also, the build was several months. Just looks easy with the summary writeup I have some free time these days, so I'm finally getting around to doing build threads vs. actually building.

[dremu]

Originally Posted by frizzen

I'm not suprised running the loading arm makes a lot more sence one direction, i've learned that my dragline crane is easier to explain and run from the Right side of machine.

Got industrious and replace the TX's two dials, which I'd been using to drive the lift and hook arms, with on-off-on momentary switches:

before



after



Now, the actuators are expecting a traditional servo-type signal, 1000...1500...2000uS, for positions from full-down to center to full-up and everywhere inbetween. This is why the dial worked so nicely, except when you're facing the wrong side. Then the dial turns to the left to make the thing rotate to the right and your head explodes

Since I already had an Arduino in there receiving iBus from the TX and running servos, it was just a matter of rewiring to insert the Arduino inbetween the TX and the actuators. Now, when you press the switch "up", it adds a little to the actuator position, and when you press it down, it subtracts a little. Had to do a little fiddling in the software to delay things ("debounce" the switch, so that it only listens to the switches every 10 milliseconds). Otherwise when you touch the switch, it adds like 500 to the actuator position and it's impossible to move accurately.

The other problem here is that we're changing from absolute position, where the dial says "Go to position 1000" (or 1500 or whatever), to relative position, where the switch just says "go up one" or "go down one." Up or down from what? I could have had the arms always start in the down position, which is reasonable, but then inspiration hit. The Arduino does have a bit of non-volatile storage (E2PROM), so the actuator positions can be saved there. Every time the switch says go up or down, the new position is stashed into the E2PROM. Then when the thing starts up again, it reads the last-saved value (making sure it's between 1000...2000 so we don't break anything) and uses that.

It's actually less complicated than it sounds, and is one of those places the Arduino shines. Changing behavior is now just a matter of changing the software. The switch delay and actuators travel limits are easy to change, upload the code, et voila.

Next up is to charge up a battery and get the PLS and the trailer and a coupla racks and make a good video of loading. It's painstaking 'cuz you load a rack from the ground onto the truck, pull up to the trailer and hook it up, move the rack from the truck to the trailer, unhook from the trailer, go to the second rack, and load that onto the truck. Whew.

Unloading is the reverse, whatever that is =))