Barry Gower
Guest
Tue Dec 06, 2011 7:10 pm
I hope someone can help me with this project.
I need a very small switch device, no bigger than about 15 mm in
diameter and up to say 25 mm thick, and powered by a small watch
battery. The device would have one main function - when you press the
switch, a light (say LED) flashes, at say 1 to 2 sec intervals for
around 30 mins, then goes off. That's it. It would also be nice if it
had a battery low function so that the LED would say flicker
continuously for say 15 seconds if the battery was below a certain
useable level.
Many thanks
Barry
Tom Biasi
Guest
Wed Dec 07, 2011 2:01 am
On Tue, 6 Dec 2011 09:10:53 -0800 (PST), Barry Gower
<barrygower_at_gmail.com> wrote:
Quote:
I hope someone can help me with this project.
I need a very small switch device, no bigger than about 15 mm in
diameter and up to say 25 mm thick, and powered by a small watch
battery. The device would have one main function - when you press the
switch, a light (say LED) flashes, at say 1 to 2 sec intervals for
around 30 mins, then goes off. That's it. It would also be nice if it
had a battery low function so that the LED would say flicker
continuously for say 15 seconds if the battery was below a certain
useable level.
Many thanks
Barry
The circuit it's self is rather simple. The first requirement can be
done with a 556 chip. The hardest part is your size requirement.
Can you work with SMT?
Tom
JeffM
Guest
Wed Dec 07, 2011 9:46 am
Barry Gower wrote:
Quote:
no bigger than about 15 mm in diameter and up to say 25 mm thick,
As Tom said: Surface-Mount Technology.
Quote:
when you press the switch,
Selecting a part that reduces the size of *that*
will be your biggest packaging problem.
Quote:
a light (say LED)
What else would it possibly be?
Quote:
flashes, at say 1 to 2 sec intervals for around 30 mins, then goes off.
The first thing you do when learning how to use a microcontroller
is to get it to flash a LED.
This one-chip solution fits your size requirements well.
Enough said?
Quote:
It would also be nice if it had a battery low function
A battery-low indicator that uses up yet more battery power
is so counter-intuitive.
A microcontroller could use its onboard A/D converter to do this,
however.
Isn't there a high school or community college full of nerds
somewhere near you?
Guest
Wed Dec 07, 2011 5:31 pm
On Tue, 06 Dec 2011 20:01:45 -0500, Tom Biasi <tombiasi_at_optonline.net>
wrote:
Quote:
On Tue, 6 Dec 2011 09:10:53 -0800 (PST), Barry Gower
barrygower_at_gmail.com> wrote:
I hope someone can help me with this project.
I need a very small switch device, no bigger than about 15 mm in
diameter and up to say 25 mm thick, and powered by a small watch
battery. The device would have one main function - when you press the
switch, a light (say LED) flashes, at say 1 to 2 sec intervals for
around 30 mins, then goes off. That's it. It would also be nice if it
had a battery low function so that the LED would say flicker
continuously for say 15 seconds if the battery was below a certain
useable level.
Many thanks
Barry
The circuit it's self is rather simple. The first requirement can be
done with a 556 chip. The hardest part is your size requirement.
Can you work with SMT?
Tom
Or learn to "roll your own"
http://www.picaxeforum.co.uk/
Jasen Betts
Guest
Thu Dec 08, 2011 11:44 am
On 2011-12-07, JeffM <jeffm__at_email.com> wrote:
Quote:
Barry Gower wrote:
no bigger than about 15 mm in diameter and up to say 25 mm thick,
As Tom said: Surface-Mount Technology.
when you press the switch,
Selecting a part that reduces the size of *that*
will be your biggest packaging problem.
there's plenty of small SMD switches out there.
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