Weapon Power


But Dan! I wanna have more than just a wedge or a spike!
Worry not frail citizen of earth, I'll save you! Below are tutorials for making a Pneumatic system and an overhead hammer. Enjoy!

Pneumatics


Beware! This is some powerful junk so don't screw around unles you know what you're doing, or at least think you do. A pneumatics system generally consists of the following parts:
-resevoir (tank)
-refill mechanism
-regulator
-valve
-actuator (cylinder)

The Tank
The tank is where you store your gas of coice. Some people use compressed nitrogen because it can be stored at a very high pressure and remains gaseous. Others prefer liquified CO2 because you can fit a very large amount of it in a small area due to it being a liquid. This does mean that it cannot put out the same amount of gas in the same amount of time as a Nitrogen or High Pressure Air tank because it needs to boil off and as it does so it gets cold really quick. The colder it gets the slower it boils and the less volume you can get out in a given amount of time.

The Refill Mechanism
this is exactly what it sounds like: it refills your tank. One can be bought from a paintball supply shop for not too much money. It connects between your tank and regulator and is followed by a shut off valve for safety.

The Regulator
This is usually the gas regulator off of a paintball system or a welding tank. What it does is regulate the air pressure from the normal pressure in the tank (about 800PSI for liquid CO2, 1000-2500 for compressed nitrogen or air) to a workable pressure so your cylinder doesn't blow apart on actuation.

The Valve
The valve is what directs your gas from the source (tank and regulator) to it's final resting place (the cylinder). Generally people use 5/2 solenoid valves. 5/2 means it has 5 ports and 2 positions: extend and retract. Solenoid means it is electrically actuated and can thus be worked off of your battery via a D-switch from Team Delta. Generally you would like a single solenoid/spring return so that when the solenoid coil is powered it directs air one way and when it is unpowered it sends it the other. Be sure the valve can handle the pressure that the regulator is putting out. If any of your components are taking more pressure than they are rated at the battlebots safety crew can disqualify you. Not good.

The Actuator
The business end! The actuator uses your air to move a piston rod back and forth. What you generally want is a 2 direction rated at the same pressure as your valve. Most valves and cylinders are rated for 150PSI. To figure out how much force your cylinder puts out is to figure out the area of the flat side of the cylinder times the pressure. If you cylinder is 2 inches and circular, you want to figure out the area of that circle. the area of a circle is pi*r^2. R is the radius which is defined as 1/2 of the diameter. So you have 2/1 which is 1. 1 squared is still one. One times pi is pi which is roughly 3.14. Now times the pressure of 150psi you get 471 pounds of force! Not too shabby.

Optional stuff
What it is What it does
Piloted Valve Takes air from your air supply to assist with the switching of the flow of gas inside the valve. Allows for faster actuation and the ability to switch much larger volumes of gas quicker.
Buffer Tank Goes between your regulator and valve via a T-connector. This stores the gas boiled off from the CO2 so that your cylinder can actuate quickly. Commonly just an old dry powder fire extinguisher. Highly Reccomended.
Quick Exhaust Valve Allows gas to excape from the cylinder very quickly allowing it to actuate back and forth much faster than without them.

Now a rather shoddy picture of the whole shebang put together with all the bells and whistles.
Check out the diagram!
1. Resevoir Tank
2. Fill Mechanism
3. On/off valve
4. Regulator
5. Buffer Tank
6. Valve
7. Valve Solenoid
8. Quick Exhaust Valves
9. Cylinder
10. Battery
11. Switch
12. Receiver
Orange: High Pressure
Green: Low pressure

Got it? Good!



Overhead Hammer
This is assuming you want to do an electrically actuated hammer. If you prefer to use compressed air, just refer to the pneumatic tutorial below. Now what you're gonna need is what's known as an H-bridge, which takes current from your battery and can do three things with it depending on whatever instruction it gets: Let it pass, stop it, or reverse it so that a motor or linear actuator can go forward, stop, and backward at the push of a button. There are really two ways of going about this. Personally what I would do in such a case is get a couple of RC-switches from Team Delta but instead of actually connecting the motors to the H-bridge, connect a DC power solenoid from Grainger or a Starter solenoid from any automotive shop. What a dc starter solenoid does is take a small amount of current to activate a small electromagnet and push a ferromagnetic piece of material to complete a circuit. They typically have 3 or 4 contacts, 2 for the coil 2 for the load (the motor) for the 4 contact type and the 3 contact kind share the ground (negative) line. But how do you wire all this junk up? Good question! You will need 4 contactors/solenoids/relays/whatever, your switches, your batteries, your motors, and your noggin to hook this all up. A diagram can be found here because this is a tad too complicated to explain and best to just look at a picture. Blue is negative, red is positive.