Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Hi Ondray ...great to see your enthusiasm.
I don't want to sound like a downer. But pneumatics are the hardest robots t build. i would be really wary about doing pneumatics for you first robot. Glen has only just got a good working pneumatic flipper and he has 20 years of experience building kick ass robots…and he is a metal working genius. So they are hard. But i don't know your background. I have tried dabbling with those little gas bottles. The regulator failed and blew up the pvc tank i was experimenting with(lucky I had the camera rolling). So be careful with those things they have a hefty load of pressure is such a little tank.
...I'll start a build thread once I start getting parts in. I've got a bit of experience with high pressure systems (3000psi bomb calorimeter that nearly killed me when someone else in the lab stuffed up), but nothing like this so I'll be super careful and my design it really simple.
Tue Jul 07, 2015 7:51 pm
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide
Myles, from memory you used soda bulb's like isused in whipped cream and similar didn't you? 5cm 1.5cm diameter at a guess. Generally silver and round?
The sodastream are a lot longer. Wasn't stealth powered by one of them back in the day? I remember something questionable about the rules using them but for the life of me I can not remember why or what it was.
If you are allowed to use them the biggest issue I can see with the sodastream is it is very long. This may result in a big robot that has little weight for armor given pnumatics are typically a heavy design by the time you take into account rams, pipping, weapon itself, buffer tank if used. _________________ Remember to trust me, I am an Engineer.
IIRC stealth had a connector which just dumped CO2 (potentially liquid) by pushind down the pin on the sodastream bottle. This was unregulated and went into a vessel (think it was a tyre pump) which could definitely not take the 700psi of full pressure.
It worked and never exploded but it made people feel uneasy.
This is purely from memory. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Wed Jul 08, 2015 8:42 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Stealth has a proper ram, not a bike pump. It was that it was using heat hose for piping that made people uneasy. _________________ https://www.halfdonethings.com/
Wed Jul 08, 2015 8:46 am
DumHed Experienced Roboteer
Joined: 29 Jun 2004
Posts: 1219
Location: Sydney
the hose was car vacuum line, which was intentionally used because it would burst well before any of the other parts.
Some people thought that was somehow unsafe - but when the only failure mode was a burst rubber hose venting some CO2 inside the robot, inside the arena - I think it was pretty safe.
Nothing was pressurised unless the weapon was firing.
The bottle still had its factory fitted burst disc and pin valve.
The ram had been modified with vent ports so it could not hold pressure once it was extended past about 75%
The firing control system would only open the valve when the ram was less than ~30% extended.
Some people didn't like that it didn't have a pressure gauge on it - because someone's rules somewhere required a gauge.
It would have been useless since you could only read it while firing the weapon - and in my experience gauges don't like shock or vibration, and the only near miss I ever had safety wise with pneumatics was a gauge randomly exploding on the bench and sending the glass flying past my head. _________________ The Engine Whisperer
- fixer of things
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Probably not with a commercial mini compressor - they don't go much over 150 PSI and the small bore on the pump would mean a slow recharge. Glen was building a 2 stage compressor powered by a huge Scorpion motor, not sure how it worked though. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
So from conversations with glen I believe a lot of the paintball guys are using high pressure air. Or Nitrogen instead of C02 now as the liguid is a pain to deal with.
So in theory you could pressurise these bottles using a two stage compresssor.
However full pressure/low pressure doesnt really make any sense when you using a compressor. Difference is really whether you have a regulator or not on a bottle.
Most car compresssors dont go over 100Psi. Or well they will but very very slowly. However at 100Psi you can still get pretty decent flips and you can always make a bigger surface area on your ram if you can get the flow. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Wed Jul 08, 2015 10:53 am
DumHed Experienced Roboteer
Joined: 29 Jun 2004
Posts: 1219
Location: Sydney
yeah if you're going to have an onboard compressor you're better off running lowish pressure. It will be a lot more efficient and much simpler.
You'll never get full pressure CO2 style launches, but you can definitely do a pretty decent flip.
El Bravo went pretty well with a couple of 2L coke bottles as the air supply (no onboard compressor) _________________ The Engine Whisperer
- fixer of things
Wed Jul 08, 2015 11:08 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Ballistic from Team Rotwang used two 150psi compressors to pressure a tank to power the pneumatics. Worked fairly well from what I remember.
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
Low pressure compressor setup would be fantastic for an effective flipper. Stick a huge outrunner on the compressor with a small buffer and that's done
Still need to finalise my testing on the co2 robot but perhaps only 350psi or so is needed for equivalent co2 power... Uber compressor could achieve that easy We'll see. _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Wed Jul 08, 2015 12:12 pm
Daniel Experienced Roboteer
Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast
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We'll see.