Piezo hit light help

CDRIVE

Joined Jul 1, 2008
2,219
Could you please tell me what is being used to shoot at the Piezo target? Tapping a Piezo vs. shooting projectiles at it is hardly the same thing. Please don't tell me a .30-06. :D
 

CDRIVE

Joined Jul 1, 2008
2,219
So if I understand you right, I will have to change C3 to a 100pF capasitor or so, to make the piezo more sensitive?
Note exactly. Reducing the val of C3 should increase the response time of Q1.

so what do you think would be best, a predrilled copper board with dots, or a predrilled copper board with lanes.
I think you should use the pre-drilled copper clad boards that are readily available, but this should not be done until all your breadboarding is done!

I have read that 2N7000 can be swapped out with a BS170 (wich are easier for me to get) is that true?
The 2N7000 should be fine.

I was wondering what to do if I want two piezo's, so if one gets shot I can still shoot, using the other one for triggering. I guess it is easily done, by putting another piezo in parallel with the other one, but I may be overlooking something?
I'm not sure. I would think so, but I would prefer to get confirmation by other members.
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I am shooting a 6.5x55 swedish mauser, so I hope the piezo is sensitive enough for that.

If I understand you right, then the sensitivity will not be affected by changing C3 to a lower value?

The breadboard works, so I think I will solder it together today. I just need to get a copper board, so thats why I asked about what type of copper boards to select.
 

CDRIVE

Joined Jul 1, 2008
2,219
I am shooting a 6.5x55 swedish mauser, so I hope the piezo is sensitive enough for that.
Are you kidding me? I was being facetious! I thought this was like..... uh..... a pellet gun! I would think that a rifle round like that shouldn't have any problem making that Piezo sing!

If I understand you right, then the sensitivity will not be affected by changing C3 to a lower value?
I can't Spice a Piezo (as a signal source), because there's no way to simulate striking it. So I can only simulate this as best I can. C3 has been in your circuit prior to me entering this thread. Personally, I don't see a need for it, except for noise suppression to the Gate of the FET. Have you tried reducing C3 to 100pF? I believe it would increase the circuit response quite a bit.
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I will try to reduce it, just to see what happens. I will go to my local electronics store today and buy some stuff so I can get it all nice fitted into a box. I was thinking of changing the LEDs to 10mm's. And I think I will put them in series. I also think that I will change the voltage source to 9 volts, so the circuit can run on one of those batteries, which will save some space in the box. I have changed the resistor infront of the LED series to fit those, so they dont burn.

I was thinking of getting a bigger piezo, like a 35mm one (I have a 23mm atm) and then solder a jack kabel to it, so it can be changed very quickly if the piezo gets a 139gns bullet through it. I also think I will add a switch to turn it on and off.

I think it will be a very fine package when its done. I see if I can load up some pictures when its all done.
 

CDRIVE

Joined Jul 1, 2008
2,219
Just to satisfy my curiosity, could you please describe the target? I can't seem to get my head around how a Piezo survives this kind of abuse. I have to assume these are not your standard paper targets stapled to a cardboard backing. :confused:
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
Well, the idea came up because I saw it done by the danish military and some guys wanted to copy it and made some versions of it. They used a piezo and attached it to the back of a piece of wood. On top of the piece of wood they placed a piece of round wood (the target). It all looks like a lollypop and it gets hammered into the earth. So you dont shoot the piezo, but a piece of wood that is attached to it. I havnt tried it out yet, so I dont know if it will work like I expect, but others have done it with good results.
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
I have bought some 10mm 6000mcd red LEDs so I hope 3 of them will do the job. Else I have also bought a relay, so I can power up something bigger if needed. But I just need to see the shot in my riflescope, so I hope its enough. What do you think?
 

CDRIVE

Joined Jul 1, 2008
2,219
Well, you can always set up a mock target down range, with LEDs already lit and test to see if you can see them on a bright day.
 
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