First time building a flipper robot

[daveimi]

I'm building a lin-ac flipper! It's quite easy although how much flip it will have is debatable!

It's worth noting that Trev from Mighty Mouse Team runs a featherweight on low pressure I think and can also make you a lot of the hard to find bits.

To build a leccy flipper we're having a go with a half ton lin-ac placed right next to the arm pivot. The maths say it should still have 30-40kg of lift at the tip and will hopefully be quite quick when going off.

It may also be worth mentioning that a lot of the big flippers use the ram right by the pivot to make it deliberately mechanically inefficient.

[Danny B]

Ok, here are the components I've managed to source out so far.

2 x 12v Gimson GR02 motors
12v 3700mAh NiMH battery
Transmitter and receiver package from Scot-Bots (the people who supplied my current bot)
50mm bore, 100mm stroke ram
2 x 12oz paintball CO2 tanks
125mm Banebots wheels


There are, however, a few things I still need. If anyone can point me toward some good, low-cost ESCs it would be much appreciated. Also, would 5mm aluminium be sufficient enough armour for non-spinner battles?

[maddox10]

Why 2 12 oz tanks in a LP machine?
24Oz is 380 liters of CO2 @1 bar. Each action of your flipper uses 4 liters , max.

The cheapest useable escs are third hand electronises.
Best bet, the BotBitz 30A.
Then you can look at IBF 30A 2 channel speedo, a very nice piece of kit, but with £100 I guess above your budget. Also, not available second hand. The teams using those swear by it.

But best Bang for the Buck, TZ85's. Less cheap, but there isn't a featherweight brushed motor that can't be controlled, inside the voltage limits.

5mm ali.... depends on quality. If it's 2000 T1, that's just a tad tougher than cold butter, 7075T6 is almost as strong as steel.
But for most purposes in non spinner combat, yes, it will do. On the other hand, 10mm HDPE does the job as well, and weights half of 5mm ali.

[Danny B]

I should have probably mentioned about the tanks. I was planning to use a 12oz as the main tank anyway, but I also calculated that a 12oz tank is the perfect volume to use as a buffer tank for the ram I'm using. Can I get away with a smaller main tank?

[maddox10]

A paintball bottle as low pressure buffertank is pure waste of weight. For that there are better solutions.

And, if we keep the 4 liter per action, A 12 oz bottle contains 190 liter of gas @1 bar. 47 actions @10bar, lets say 35 real life.

A 9 oz bottle contains 138 liter of gas. Thats 34 actions op paper. 25 real life.

Lower the pressure to 6 bar, and the equation changes equaly.

[Danny B]

So 25 actions means 12 good flips. Given that the matches are only 3 minutes long, I think I could get away with a 9oz bottle. What would you recommend I use as a buffer tank?

[maddox10]

I ment 25 good flips, is your driving skill is up to it.

And I can't recommend anything commercial for a low pressure tank with a volume of 0.6 liter.
It's not something needed a lot in daily life.

[Danny B]

Ok, saving is now underway to get enough cash for components. Meanwhile, I've been narrowing down my choices of name and colour scheme, and I've got it down to two.
So I'm throwing it open for you to decide, Eclipse or Krypton 85?
Eclipse sketch 2.pngKrypton 85 sketch.png

[Danny B]

Moving on to the solenoid valve, does anyone have any recommendations regarding port size and whether I should go with a double-acting or a spring return?

[Danny B]

I'm looking at some braided steel paintball hose, but I can't find any with threads larger than 1/8 inch and I'm worried that this could restrict CO2 flow. Does anyone have an alternative recommendation?

[maddox10]

I prefer the Krypton 85 idea.


On solenoid valve. The bigger the valve, the faster it can feed the ram to full glory. With the size of ram you're contemplating, industrial standard is 1/4" bsp in and outlet. That's restricting in itself.
Most FP machines use 1/2" bsp inlets.
You can find 1/4 bsp valves from "known brands" easely enough on Ebay or such, affordable. Otherwise you could try Chinese copies.
I would use single acting. Less complicated, less parts, less gas used per action. So what you can search for is a 1/4" bsp 3/2 valve. Return to be done with bungee cord.

The braided stainless steel hose. Why? 1 paintball bottle, regulator (best bet, a Trevor regulator) directly attached to that. From there a low pressure hose to the buffertank, and that can be a small hose. Buffertank, valve and ram connections need at least a 8mm hose.

[Eventorizon]

Eclipse or Krypton 85?
[ATTACH=CONFIG]4368[/ATTACH][ATTACH=CONFIG]4369[/ATTACH]

Eclipse for me! I would add some wheel deflectors to each design though, just something to stop the wheel getting hit from the front, a small raised section would do. You need not cover the wheel entirely just make sure the leading edge is covered.

[calumco]

move your wheels forward a bit otherwise youll find it aweful to drive then u can have your gas bottle laying sideways along the back too where your motors etc wudda been

[Danny B]

The braided stainless steel hose. Why? 1 paintball bottle, regulator (best bet, a Trevor regulator) directly attached to that. From there a low pressure hose to the buffertank, and that can be a small hose. Buffertank, valve and ram connections need at least a 8mm hose.

I've placed an order for a Trev reg, I should be getting it at the Barnsley event. I do already have a 5/2 spring return valve, but I can easily turn it into a 3/2 if I plug one of the outlet ports.
As for the 8mm hose, would this be a reasonable choice? http://www.indequip.co.uk/catalogue/...b-a22100cdc83c

[Danny B]

move your wheels forward a bit otherwise youll find it aweful to drive then u can have your gas bottle laying sideways along the back too where your motors etc wudda been

That might be difficult. Problem is, the ram is mounted right at the back, so I can't put anything across there, and moving the motors more central means I can't fit the bottles down the sides as per the original plan.
What if I put the wheels up near the front instead? the tail might swing a little wide, but I would have very precise control of the business end of the robot.