Launching circuit - cool and simple?

Davidvaini · Sat May 28, 2011 4:48 pm

I think I understand it now. IF the switch in my picture above, was flipped to the right, i could press the button to fire, or if I had a switch hooked up to that plugin, i could use that switch to fire.. and if I didn't have a switch hooked up to that, I wouldnt need a jumper either, I could just use the button to fire... cause its and "or" and not a "and"..

mind you this is without the diode, i was just seeing If I understand the nature of using a parallel circuit in conjunction with the on/off/on switch.

al-xg · Sat May 28, 2011 7:08 pm

Does the charging mode have to be separate from the safe mode ?
The charger should just have to be in parallel with the battery, an could technically even left plugged in and charging when firing etc... ?

I didn't suggest it initially as there was only one "plugin", but as now there are two...

Technician1002 · Sat May 28, 2011 7:13 pm

An armed LED can be connected with a resistor in parallel with the switch and jack. The LED with the resistor won't pass enough current to fire the solenoid, but would clearly alert you that the system is armed. A fire button with the LED in it would do the job nicely.

Many rocketry systems do this. The LED won't light if the ignition is not connected

Davidvaini · Sat May 28, 2011 7:26 pm

It doesnt matter to me if I have an LED, never mentioned it actually. I know it would be a nice indication that it is armed, but the safety thing is just so I dont pump the trigger while caring it, Ill know its armed when the toggle shield is fliped up. It is meant for a shoulder fired law launcher, so an indication light isnt exactly needed. But that is a good idea if I decided at a later date that an LED is needed.

I am most likely going to go wit Dewey's circuit, but I just wanted to see if my circuit that I just drew would work. That is all.

dewey-1 · Sat May 28, 2011 7:57 pm

David I updated version 3 schematic.
Removed the jumper J2 in Normal Mode because it is not needed.

I forgot to remove it when I went with version 3.

Davidvaini · Sat May 28, 2011 8:07 pm

dewey-1 wrote:David I updated version 3 schematic.
Removed the jumper J2 in Normal Mode because it is not needed.

I forgot to remove it when I went with version 3.

yeah I figured, since if the jumper was in, it would complete the circuit and i would be doing that anyway by pressing the fire button.

evilvet · Sat May 28, 2011 9:26 pm

Hi David

A suggestion for a safety interlock that I use on a lot of firing circuits: wire a mono banana socket in series. Then get a banana jack and solder across the contacts.

Result, if the banana jack is removed the circuit is open and cannot be closed by someone wondering "what's this switch do?" Missile switch covers are all very well but people do get curious. The key switch idea is the same as mine but mine is a lot cheaper

Put the banana plug on your key chain with a big bit of red ribbon tied to it. When you are ready to fire, plug and pray.

Cheers

Technician1002 · Sat May 28, 2011 9:29 pm

My main safety against accidental discharge is to ensure the cannon is not filled until just before firing it.

evilvet · Sat May 28, 2011 9:33 pm

Which falls into line with my range safety officers mantra "if all the people killed with unloaded guns lined up, it would be a big queue"

Every cannon is loaded and charged at all times, every magazine is full and every safety is faulty. Assume that at all times and you may survive to play another day.

Davidvaini · Sat May 28, 2011 9:53 pm

So I tested my circuit and I am working on Dewey's circuit in Yenka.. which is a pretty cool and powerful program... and its free.. which is pretty sweet...

As far as the safety is concern, it is more so that when I am positioning myself to aim at a vehicle, I don't accidentally hit the fire button and fire. Other than that, it is for more of a military feel. The device will be loaded at the time of use, both with air and with the projectile. The pressures and projectiles used are going to be safe just in their very nature.

Now if this was some kind of awesome hybrid or something like that, I would assume all worst case scenarios and plan my multiple safety's etc, but honestly for this low powered project used for milsim events anyway, it honestly just needs to make sure I dont have a premature launch.

So the fact that the cover needs to be lifted up, the switch needs to be fliped to the on position, and the fire needs to be pressed in order to fire the thing, is far within my needs or any fields requirements.

As always, I am going to treat it like the gun is loaded with dangerous projectiles, with high pressure, and that the safety is off.. that goes without saying.