first multi stage gun
andy73, Thu Jul 26 2007, 04:18PMhi all im new here and to electronics and im having trouble understanding how to make the optical trigger system. i have some flash units from cameras and some optical gate circuits, well i just cant get the optic to fire, i m not sure if iv made it wrong but all i want is for the projectile to break the beam and trigger the flash unit
can anyone help me , iv added a pic of what i have so far i just need to get help on how to get the optical trigger to work the flash unit
Re: first multi stage gun
OZZY, Thu Jul 26 2007, 05:21PM
It looks like you are trying to use the 2n2222 in the emitter follower configuration. You should take the lower end of the 10K resistor to ground and then take the output from the emitter to the SCR gate via a current limiting resistor. The SCR gate will be pulled up to 2 or 3 volts when the transistor is "on" you can then calculate the value of resistor you need to get a sensible current.
OZZY, Thu Jul 26 2007, 05:21PM
It looks like you are trying to use the 2n2222 in the emitter follower configuration. You should take the lower end of the 10K resistor to ground and then take the output from the emitter to the SCR gate via a current limiting resistor. The SCR gate will be pulled up to 2 or 3 volts when the transistor is "on" you can then calculate the value of resistor you need to get a sensible current.
Re: first multi stage gun
andy73, Thu Jul 26 2007, 05:48PM
hi ozzy thanks for the info but unfortunatly in have no idea what you mean, like i said i dont know much or anything about electronics really, so i need really simple instructions.
i also dont see how a scr can work as a switch?????
andy73, Thu Jul 26 2007, 05:48PM
hi ozzy thanks for the info but unfortunatly in have no idea what you mean, like i said i dont know much or anything about electronics really, so i need really simple instructions.
i also dont see how a scr can work as a switch?????
Re: first multi stage gun
GreySoul, Thu Jul 26 2007, 11:53PM
To trouble shoot things of this nature you really do have to have a basic understanding on electronics...at least the terminology / vocabulary. Of course it's a chicken and egg thing... this IS a good starter project.
I'd also suggest you get a basic book on electronics and theory. I learned the most early on from a simple little radio shack electronics project book.... and later studying for my amature license... and now from these guys :)
Point is, doing it from a kit (or pre-tested design) can only really teach you so much - books are great for the rest. most people here are happy to help one another, but you have to speak the secret code :P
ANYWAYS.... back on track....
This thread should give you some better insight to optical triggers:
Ozzy - I've built this circuit - it works, but you have to really adjust that pot to get the power low enough on the PT to be sensitive enough to trigger... the problem is there's too much leakage of light around the projectile, so you're not fully cutting the path, hence no trigger...
Andy: If you cover (or disconnect) the LED does the circuit trigger? Also, try making a little hood over each of the optical components with tape or heat shrink tube, to limit the angle of each part, and line them up....
Dunno... that's my 2¢
-Doug
GreySoul, Thu Jul 26 2007, 11:53PM
To trouble shoot things of this nature you really do have to have a basic understanding on electronics...at least the terminology / vocabulary. Of course it's a chicken and egg thing... this IS a good starter project.
I'd also suggest you get a basic book on electronics and theory. I learned the most early on from a simple little radio shack electronics project book.... and later studying for my amature license... and now from these guys :)
Point is, doing it from a kit (or pre-tested design) can only really teach you so much - books are great for the rest. most people here are happy to help one another, but you have to speak the secret code :P
ANYWAYS.... back on track....
This thread should give you some better insight to optical triggers:
Ozzy - I've built this circuit - it works, but you have to really adjust that pot to get the power low enough on the PT to be sensitive enough to trigger... the problem is there's too much leakage of light around the projectile, so you're not fully cutting the path, hence no trigger...
Andy: If you cover (or disconnect) the LED does the circuit trigger? Also, try making a little hood over each of the optical components with tape or heat shrink tube, to limit the angle of each part, and line them up....
Dunno... that's my 2¢
-Doug
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