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Re: Hydraulics and Pneumatics

Posted: February 21st, 2010, 9:00 pm
by Primate
penclspinner wrote:
cypressfalls Robert wrote:
Primate wrote:I don't mean to judge your device, but make sure those dominoes are completely reliable. I had an issue with wind power on my machine--it was occasionally trigged by the mousetrap at the beginning (rather than the fan), which short-circuited half our events. It would be heartbreaking if someone bumped your table while the device was running and started the domino chain.
I don't think the judges would allow anyone to even touch the same table you would be working on.
I am sure that if the judges were in absolute control of the event it wouldn't happen, but then again it's not like anyone ever asks for permission to bump the table either, it just seems to happen accidentally
Well, you could potentially run into it yourself, too. Crazy stuff happens. For example, at regionals I managed to rip the bandaid off of a cut on my finger while tying up the balloon, and it started spouting blood everywhere. It was nasty, but I didn't want to deal with it since neither of my team members were capable of setting up the machine. So my mission is now stained in blood. At least it was an excuse for connecting the battery backwards :oops:.

Re: Hydraulics and Pneumatics

Posted: February 26th, 2010, 11:08 am
by Xenarian
I had the idea to use a single syringe for a sort of piston system for my hydraulics. I cut off the end of one of them, and put a second plunger into the cylinder of the cut syringe.

But my plungers have WAY too much friction to move with what I have. I tried sandpapering them, but that doesn't help.
Does anyone have syringes that they can move with a simple solenoid or geared electric motor? Or would I be better off using a windshield fluid pump?
My state's rules require that I not have any power source exceeding 10v, so I'm limited in that sense. But I'm not running into any space problems on my box. Lots of room left :)

Re: Hydraulics and Pneumatics

Posted: February 26th, 2010, 4:04 pm
by Flavorflav
Xenarian wrote:I had the idea to use a single syringe for a sort of piston system for my hydraulics. I cut off the end of one of them, and put a second plunger into the cylinder of the cut syringe.

But my plungers have WAY too much friction to move with what I have. I tried sandpapering them, but that doesn't help.
Does anyone have syringes that they can move with a simple solenoid or geared electric motor? Or would I be better off using a windshield fluid pump?
My state's rules require that I not have any power source exceeding 10v, so I'm limited in that sense. But I'm not running into any space problems on my box. Lots of room left :)
Be careful - I put in a clarification about solenoids with soinc and was told that they were illegal. They didn't post it (they hardly post anything anymore) so you might get away with it, but at the least it means that you might be 2nd tiered for using one.

As for your question, yes, we are moving a plunger with a gearmotor.

Re: Hydraulics and Pneumatics

Posted: February 27th, 2010, 7:43 am
by Xenarian
WHA!? Solenoids illegal!?

Haha, I used a solenoid to pop the balloon at the Loyola meet. They didn't say anything about it :)
And I don't see why it should be disqualified. It's basically an electromagnet. Or a linear motor, if you will. There's nothing in it but some magnet wire (they allowed wire, yes?), constituting a resistor. No diodes of questionable legality, etc...
That blows my mind.

So, I guess I'll have to switch to a motor. No big deal.

So, how did you get this geared motor? I got a little one at Radioshack, but there isn't a gear set that comes with it. Could you point me in the right direction to get one please?

Re: Hydraulics and Pneumatics

Posted: February 27th, 2010, 8:01 am
by Sir_L_Jenkins
How are solenoids illegal? It's just a EM rigged with a hallowspace to allow a metal to be pushed in one direction... All of which are legal materials, are you sure it wasn't some odd regional/state rule, and not applying to the national level? I've used them in both regionals and invitationals without any problems.

Or the other thing I could see is that they were interpreting your clarification to the EM step? That could be seen as you need just a basic EM and not a solenoid, but that's the only thing I can think of.

If they are indeed illegal I need to chance quite a bit of my device...

edit:
Flavorflav, could you perhaps post your email/response from soinc?

Re: Hydraulics and Pneumatics

Posted: February 28th, 2010, 4:48 pm
by Flavorflav
Here you go. Not a lot of ambiguity there. I was surprised, too.
no-reply@soinc.org to me
show details Feb 9
Yes.

The original question is included for your records; there is no need to
respond unless you feel there is an error.
=========================================================
ORIGINAL MESSAGE:

Are commercial solenoids considered unapproved electrical components?

Re: Hydraulics and Pneumatics

Posted: February 28th, 2010, 5:16 pm
by Sir_L_Jenkins
Hmm, indeed that is odd. Oh well, I suppose I'll just replace my commercial solenoids with homemade electromagnets that just so happen to have hollow spaces that allow some iron to be propelled in one direction. I feel like they really should post this on the official clarifications as solenoids are very commonly used and could get a lot of people DQed for apparently no reason if the judge knows about this.

Re: Hydraulics and Pneumatics

Posted: February 28th, 2010, 7:17 pm
by Flavorflav
I don't know why they don't just post them all. I'm sure they get an awful lot of repeat questions that would never have have been submitted if they had posted their answer the first time.

Re: Hydraulics and Pneumatics

Posted: March 1st, 2010, 2:38 am
by Flavorflav
Xenarian wrote: So, how did you get this geared motor? I got a little one at Radioshack, but there isn't a gear set that comes with it. Could you point me in the right direction to get one please?
Sorry, didn't notice this part. We are using a little Tamiya kit gearmotor, which I believe we got from Hobbylinc.com. Efficiency is not great, with all those cheap plastic gears, but it gets the job done.

Re: Hydraulics and Pneumatics

Posted: March 3rd, 2010, 6:58 pm
by Xenarian
I requested two clarifications a week ago, and haven't gotten responses for either of them!
Where exactly did you guys send your clarification requests? I did to the people listed on my states Olympiad website. I guess that was the wrong place?