Barrel mounted shot counter

[Kingluke23]

You can use photoelectric cells or proximity sensors. Ive used them on machinery but never for this though.
The photocells are pnp or npn so should give you a logic output

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[No1_sonuk]

Re: Barrel mounted shot counter

No they won't. Phototransistors (the "pnp or npn" you're on about) don't give a logic output by default, they're analogue and need a processing circuit of some kind.
The ones sold for machinery already have those circuits built into the module, and are too big to fit in the gun.

"Photoelectric cells" is too general a term for this application, as it includes solar panels and LDRs. Both of which are unsuitable for this application.

The speed required for BB sensing needs a phototransistor or photodiode. Nothing else is fast enough.

These are general info on the two. Hopefully these links don't fall foul of forum rules.
http://www.radio-electronics.com/inf...transistor.php
http://www.radio-electronics.com/inf...hoto_diode.php

[Mavrik]

Re: Barrel mounted shot counter

The schmitt trigger should overcome the analouge problem and ensure that it stays as a digital signal. Nearly on to building it, instead of a rather bulky set of three counters and three decoders, im using a PICAXE chip, most likley a 40 leg one which gives me enough legs for a switch which turns it the display on temporairly (to save on battery as an LED display uses a fair amount of power compared to an LCD but the circuitry is more complicated and can't be read in the dark unless a baclight is used which adds more to siz and complications,) 21 legs for the display and another for the magwell reset switch and one for the input along with all the other pins that are useless in aplication. The actual sensor will most likley be one of these:
http://uk.farnell.com/optek-technolo...ral/dp/1497862
paired with one of these
http://uk.farnell.com/jsp/search/pro...ote-1226443-pr
these are side facing so all I need to do for the casing is machine a couple of slots in on opossing sides and mount them in ther and slip a cover over that to protect them. Should be simple right?

[Mavrik]

Re: Barrel mounted shot counter

Right well on my way to manufacturing casing for the sensor. I have 2 pieces of speed aluminum (which by the way is the best thing on the planet to machine, especiall in comparison to the black rolled steel bar i've used in a seperate project which is the devil) The first is the actual case that is 50mm long and 25 wide round section. Into this there is a 20mm deep 19mm bore and a 7mm hole going through that. The 19mm bore is a rough bore and is done because as it turns out its really hard to do internal thread cutting up to a shoulder so instead i am threading te second piece of aluminumm and stamping this into the first piece. Hopefully that should work

[-=256=-Swerve]

Re: Barrel mounted shot counter

thought: could the readout be projected within a modified eotech or holosight?

[Pidge]

Re: Barrel mounted shot counter

Didn't think to search for a thread on this! I am working on this too and have a working prototype on a breadboard. Just need the time to tweak the code and green board it (probably a blue board lol) and I'm ready to go.

Ill keep an eye out on this thread to see how you get on.

[No1_sonuk]

Re: Barrel mounted shot counter

The 19mm bore is a rough bore and is done because as it turns out its really hard to do internal thread cutting up to a shoulder so instead i am threading te second piece of aluminumm and stamping this into the first piece. Hopefully that should work

As with external threading, it's better to not go right up to a shoulder, and 20mm depth is more than enough to allow you to "lose" a couple of mm for a groove at the end.

Oh. I just thought... Are you using a tap for the threading? That could give you issues.
I use a single-point threading tool in a lathe for such jobs. That gives you the option of doing all the weird thread size/pitch combinations used in some airsoft applications (e.g. M13 x 1mm - TM MP5K PDW muzzle thread and M22 x 1mm - S-Thunder 40mm grenade dome/cap thread).

The collar idea will work, but you might need to re-finish the thread afterwards - the fitting may deform it a bit.
Make it an interference fit, and aluminium's natural tendancy to bind together will make it nigh-on impossible to separate.