Questions/builds thread.

[Bodge Job]

Re: Questions/builds thread.

Yeh, nylon 6 also gets more brittle in the cold, we were makeing some new side panels last year, and huge chunks broke of, as we were using an electric planer on it...

[Ellis]

Re: Questions/builds thread.

Well, it's been a while! We're back at it again, now that my dad's work has opened up a little. We've spent the past few days designing and starting to build our lifter. We're going for a 4-bar, conventional drill and threaded rod, etc. We've cut some 2cm x 2cm box steel and got it into the right shape, welding (when I say welding I mean... uh ) a little along the way. Tomorrow we'll do some more cutting and *cough* welding and gradually piece it together. Hard to explain what we're doing, I'll put pics up as we go.

Today we bought some bits and bobs to make the legs for the lifter, so once we have the design in place the actual build process shout be quite quick. Tomorrow we'll order the 15a Electronize ESC for the lifter motor (we thought it would be nice to have it proportional). Our motor mount is going to be quite interesting, it involves circles of wood/plastic, a T of PVC and rubber bands .

The weight limit is slowly creeping up on us. The machines currently weighs a bit over 8kgs. We will probably have several kilos of lifter business, leaving us with not all that much to make it spinner and axe proof.

Will keep this posted.

[PJ-27]

Re: Questions/builds thread.

I believe there are better options to control a lifter mech than a 15a ESC. Never built one so I don't know what it is, but thought I'd warn you before you fork out.

I've in the past thought about using car electric window relays, as these stop when a current past a certain amount is drawn (when the window can't go any further and the motor stalls) but that's me thinking with my Bitza hat on.....

[harry hills]

Re: Questions/builds thread.

i use a 15a electronize for my lifter, seems fine.

[PJ-27]

Re: Questions/builds thread.

Aren't you worried about stalling it?

[mattsdragons]

Re: Questions/builds thread.

i used one for my claws, very reliable system, just a shame my claws were crap

[harry hills]

Re: Questions/builds thread.

lifted a heavyweight shell without blowing so its a pretty good system

[Ellis]

Re: Questions/builds thread.

If the lifter goes to plan it shouldn't stall when lifting an opponent. It will probably only lift half the weight of another machine in combat, and considering the motor unit can lift 60kgs comfortably at 12v without slowing down, it should be able to lift 8ishkgs in battle at 18v in its sleep, even with the ratios in mind. The only points at which it could stall are when it's fully extended or fully retracted, though with the precision of the proportional control and some practice that shouldn't be too much of a problem. Even if I do overshoot, the Electronize are tough little buggers, I think it'll be fine.

Hopefully some pics will come later today.

[psycho_fling]

Re: Questions/builds thread.

i use to run a lifter on an electronize switch smae principle as you are running on but the travel was stopped by limit swithces avoiding the possibility (in theory) of it ripping itslef apart

[Ellis]

Re: Questions/builds thread.

I don't quite understand how limiting switches can be setup. My mind immediately takes me to micro-switches that are activated by the arm when it passes them, killing the circuit and thus limiting its travel. Of course though, that doesn't work; the circuit is broken and the arm can't be retracted.

So, how do I do it?

[razerdave]

Re: Questions/builds thread.

I have a diagram for a limiter switch circuit at home, I'll post it tonight when I am home.

[Laser]

Re: Questions/builds thread.

use diods and microwtiches. when the nut on the threaded rod hits the microswitch it will stop the motor going any further by cutting it off.

[razerdave]

Re: Questions/builds thread.



The 'Ds' are diodes, and the info at the bottom there is the component you're looking for. Go you your local maplins and they'll sort you out, and also, the diodes have white lines on the which represent the lines on their symbols on this diagram.

[Ellis]

Re: Questions/builds thread.

Oh, of course! Brilliant! Makes perfect sense, haha. Well, ordered two large micro-switches, a pack of 12 1N5408 diodes and a 15a Electronize ESC.

Ended up not doing any buildy/designy stuff today, hopefully we will get to that tomorrow.

Thanks again.

[Ellis]

Re: Questions/builds thread.

Took us a bit longer to get going again than expected!

Diodes, microswitches and ESC have arrived, so all that's waiting for us to catch up.

I have some pics of the lifter arms in a mocked up position, latest 3 in the album - http://s1088.photobucket.com/albums/i32 ... elentless/

We just spent an hour planning our lifter's legs and the geometry of the whole thing. We're looking for a ratio of about 4:1, giving us a ROUGH lift time of 1.5 seconds. The travel is about 8-10 inches at the tip. Pretty nippy, certainly fast enough to be useful in battle.