More about special timing device

Thinking (I know, it's dangerous) this afternoon about my need for a
special timing device led me to stop watches. If two stopwatches were
wired together with three switches such that the first switch started
started both stopwatches simultaneously and the other two switches
stopped their own single stopwatch I would have what I want. But I
can't, after spending some time online, find a pressure activated
switch that will work. I am open to any suggestions. So far I have
recieved much good advice on this project and want to say how much I
appreciate the folks who have helped me so far. I am sure I will be
able to eventually come up with a fairly inexpensive solution, but
really the solution most likely will come from someone here and I'll
just be the one implementing it.
Thanks,
Eric

 

[Jon Kirwan]

On Tue, 30 Apr 2013 17:56:36 -0700, etpm@whidbey.com wrote:

Thinking (I know, it's dangerous) this afternoon about my need for a
special timing device led me to stop watches. If two stopwatches were
wired together with three switches such that the first switch started
started both stopwatches simultaneously and the other two switches
stopped their own single stopwatch I would have what I want. But I
can't, after spending some time online, find a pressure activated
switch that will work. I am open to any suggestions. So far I have
recieved much good advice on this project and want to say how much I
appreciate the folks who have helped me so far. I am sure I will be
able to eventually come up with a fairly inexpensive solution, but
really the solution most likely will come from someone here and I'll
just be the one implementing it.
Thanks,
Eric

This is that device where two hammers get out of synch?

Piezos (those that you'd talked about) would work fine
coupled to a microcontroller if you can place them somewhere
they won't get destroyed but will get "pinged" by the impact.

Here's a link to look at when thinking still more
dangerously:
http://www.youtube.com/watch?v=92VIEDtQKVI

A micro could easily set up the two timers you require, with
something akin to that as sensors. Not sure how you start the
timers, though. You don't say. If you had a PC nearby, that
could replace bothering with a display, since USB can
transmit the timing values to the PC via a virtual RS-232
port from almost any really cheap micro kit (plenty of
suitable ones at $10, in one-each qty.)

Jon

 

[Randy Day]

In article <4ep0o8tpli4ga043qdp1js50896d8834eo@4ax.com>, etpm@whidbey.com
says...

[snip]

switch that will work. I am open to any suggestions. So far I have
recieved much good advice on this project and want to say how much I
appreciate the folks who have helped me so far. I am sure I will be
able to eventually come up with a fairly inexpensive solution, but
really the solution most likely will come from someone here and I'll
just be the one implementing it.

A contributor on Hackaday posted about a
somewhat similar project; he used an audio
editing package (Audacity) to measure the
response of a DSLR shutter by recording
the clicks, then using the timestamp
feature to determine the interval between
sound bursts.

One microphone, one pc, no damage.

I can't paste a link from this pc, but you
can search Hackaday for the title:

"DSLR performance measured with audio
editing software".


HTH

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Tim Wescott]

On Tue, 30 Apr 2013 17:56:36 -0700, etpm wrote:

Thinking (I know, it's dangerous) this afternoon about my need for a
special timing device led me to stop watches. If two stopwatches were
wired together with three switches such that the first switch started
started both stopwatches simultaneously and the other two switches
stopped their own single stopwatch I would have what I want. But I
can't, after spending some time online, find a pressure activated switch
that will work. I am open to any suggestions. So far I have recieved
much good advice on this project and want to say how much I appreciate
the folks who have helped me so far. I am sure I will be able to
eventually come up with a fairly inexpensive solution, but really the
solution most likely will come from someone here and I'll just be the
one implementing it.
Thanks,
Eric

This was two hammers whacking pins into a panel or some such?

It just occurred to me that an accelerometer on the base will detect the
impacts, but not distinguish between them. Accelerometers on each hammer
should detect the individual impacts, if you can sort the wiring out.
Just about anything between the hammer and the pin will get beaten up in
short order...

Accelerometers aren't going to actuate the switches easily, though -- I'm
going to reiterate my advice that if you charge by the hour you should
just get an inexpensive oscilloscope. I'll bet you spent enough time
looking for ideas by now that you could have bought at least one cheap
scope, and maybe a couple of accelerometers with power supplies.

If you really need to go cheap on the accelerometers, use electret
microphones. Buy lots -- I'll bet they don't last long in that service.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

On Wed, 01 May 2013 12:32:49 -0500, Tim Wescott <tim@seemywebsite.com>
wrote:

On Tue, 30 Apr 2013 17:56:36 -0700, etpm wrote:

Thinking (I know, it's dangerous) this afternoon about my need for a
special timing device led me to stop watches. If two stopwatches were
wired together with three switches such that the first switch started
started both stopwatches simultaneously and the other two switches
stopped their own single stopwatch I would have what I want. But I
can't, after spending some time online, find a pressure activated switch
that will work. I am open to any suggestions. So far I have recieved
much good advice on this project and want to say how much I appreciate
the folks who have helped me so far. I am sure I will be able to
eventually come up with a fairly inexpensive solution, but really the
solution most likely will come from someone here and I'll just be the
one implementing it.
Thanks,
Eric

This was two hammers whacking pins into a panel or some such?

It just occurred to me that an accelerometer on the base will detect the
impacts, but not distinguish between them. Accelerometers on each hammer
should detect the individual impacts, if you can sort the wiring out.
Just about anything between the hammer and the pin will get beaten up in
short order...

Accelerometers aren't going to actuate the switches easily, though -- I'm
going to reiterate my advice that if you charge by the hour you should
just get an inexpensive oscilloscope. I'll bet you spent enough time
looking for ideas by now that you could have bought at least one cheap
scope, and maybe a couple of accelerometers with power supplies.

If you really need to go cheap on the accelerometers, use electret
microphones. Buy lots -- I'll bet they don't last long in that service.
Greetings Tim,

You're correct, I have spent a bit of time on this project. But it
will probably be worth it for one of two reasons. First, I get to
learn how to do something I'm interested in, and second it may make me
more valuable to the customer.
Eric