bluemountains George
Guest
Mon Mar 08, 2010 4:59 am
Just wondering if anyone with a newborn who has those Angelcare baby
monitors with sensor pad.
Has anyone opened up motion sensor pad? My wife wont let me and I am
dying to know how it works. There are only 2 wires and I cant
imagine its too hitech but it seems to detect baby breathing movements
through a thick mattress???
http://www.angelcare-uk.co.uk/content/201.pdf
cth
Guest
Mon Mar 08, 2010 5:17 am
On 08-Mar-10 13:59, bluemountains George wrote:
Quote:
Just wondering if anyone with a newborn who has those Angelcare baby
monitors with sensor pad.
Has anyone opened up motion sensor pad? My wife wont let me and I am
dying to know how it works. There are only 2 wires and I cant
imagine its too hitech but it seems to detect baby breathing movements
through a thick mattress???
http://www.angelcare-uk.co.uk/content/201.pdf
Never seen one, is it firm to the touch or spongy?
If the former, my guess would be pressure/resistive, if the latter then
possibly an air bladder with passive pressure sensor? Which is cheaper?
Have to watch out for punctures if it's a bladder...
--
Chris.
bluemountains George
Guest
Mon Mar 08, 2010 6:56 am
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
Jasen Betts
Guest
Mon Mar 08, 2010 9:22 am
On 2010-03-08, bluemountains George <socrates_01_at_hotmail.com> wrote:
Quote:
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
piezo's not too good at low freuency. could be a magnetic pickup? is
there any evidence of a permanent magnet - does ant part of it deflect
a compass needle.
---
news://freenews.netfront.net/ - complaints: news_at_netfront.net ---
cth
Guest
Tue Mar 09, 2010 2:27 am
On 08-Mar-10 15:56, bluemountains George wrote:
Quote:
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
So it *produces* a voltage without external supply/excitation?
bluemountains George
Guest
Tue Mar 09, 2010 5:04 am
On Mar 9, 12:27 pm, cth <a...@b.c> wrote:
Quote:
On 08-Mar-10 15:56, bluemountains George wrote:
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
So it *produces* a voltage without external supply/excitation?
yes correct, without anypower it produces up to 2v acpeaks .
the pad is 2 splitplastic pads connected together on some sort of
flexible gymbal with a few mm of rocking movement.
I cant open the pad without damaging it.
cth
Guest
Tue Mar 09, 2010 5:19 am
On 09-Mar-10 14:04, bluemountains George wrote:
Quote:
On Mar 9, 12:27 pm, cth<a...@b.c> wrote:
On 08-Mar-10 15:56, bluemountains George wrote:
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
So it *produces* a voltage without external supply/excitation?
yes correct, without anypower it produces up to 2v acpeaks .
the pad is 2 splitplastic pads connected together on some sort of
flexible gymbal with a few mm of rocking movement.
I cant open the pad without damaging it.
I read this as 2 inflexible pads with, my guess, a flexible
piezoelectric film/ribbon (such as
http://www.meas-spec.com/piezo-film-sensors.aspx) between the two. As
long as the movement never entirely stops there'll be some output (which
is what's required!)
--
FWIW,
Chris.
Baron
Guest
Tue Mar 09, 2010 10:39 pm
cth Inscribed thus:
Quote:
On 09-Mar-10 14:04, bluemountains George wrote:
On Mar 9, 12:27 pm, cth<a...@b.c> wrote:
On 08-Mar-10 15:56, bluemountains George wrote:
Its springy. The slightest tap it measures about .4 to over 2v AC
for
a sharp tap. Not sensitive to sound, just heavy vibration. I
thought
piezo but in that case wouldnt need a moving spongy plate which
what this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a
15 sec period.
So it *produces* a voltage without external supply/excitation?
yes correct, without anypower it produces up to 2v acpeaks .
the pad is 2 splitplastic pads connected together on some sort of
flexible gymbal with a few mm of rocking movement.
I cant open the pad without damaging it.
I read this as 2 inflexible pads with, my guess, a flexible
piezoelectric film/ribbon (such as
http://www.meas-spec.com/piezo-film-sensors.aspx) between the two. As
long as the movement never entirely stops there'll be some output
(which is what's required!)
--
FWIW,
Chris.
MIL has a similar device that warns us if she gets out of bed, though I
suspect that its some kind of pressure sensitive device. Its very
similar to an electric under blanket in appearance.
--
Best Regards:
Baron.
Swanny
Guest
Wed Mar 10, 2010 1:53 am
bluemountains George wrote:
Quote:
Just wondering if anyone with a newborn who has those Angelcare baby
monitors with sensor pad.
Has anyone opened up motion sensor pad? My wife wont let me and I am
dying to know how it works. There are only 2 wires and I cant
imagine its too hitech but it seems to detect baby breathing movements
through a thick mattress???
http://www.angelcare-uk.co.uk/content/201.pdf
How about a big dynamic mic, with the spongy pillow part being the
diaphragm. This would generate a voltage proportional to movement.
Swanny
Guest
Wed Mar 10, 2010 1:58 am
bluemountains George wrote:
Quote:
On Mar 9, 12:27 pm, cth <a...@b.c> wrote:
On 08-Mar-10 15:56, bluemountains George wrote:
Its springy. The slightest tap it measures about .4 to over 2v AC for
a sharp tap. Not sensitive to sound, just heavy vibration. I thought
piezo but in that case wouldnt need a moving spongy plate which what
this is.
Its designed to set off an alarm if baby doesnt move (breathe) in a 15
sec period.
So it *produces* a voltage without external supply/excitation?
yes correct, without anypower it produces up to 2v acpeaks .
the pad is 2 splitplastic pads connected together on some sort of
flexible gymbal with a few mm of rocking movement.
I cant open the pad without damaging it.
Someone is going to use one of these as a kick drum microphone one day.
Royston Vasey
Guest
Wed Mar 10, 2010 2:44 am
"bluemountains George" <socrates_01_at_hotmail.com> wrote in message
news:9491aa95-79aa-40dc-95ab-7a5d03ece3d8_at_c34g2000pri.googlegroups.com...
Quote:
Just wondering if anyone with a newborn who has those Angelcare baby
monitors with sensor pad.
Has anyone opened up motion sensor pad? My wife wont let me and I am
dying to know how it works. There are only 2 wires and I cant
imagine its too hitech but it seems to detect baby breathing movements
through a thick mattress???
http://www.angelcare-uk.co.uk/content/201.pdf
maybe its among this stuff:
http://www.patentgenius.com/assignee/GracoChildrensProductsInc.html
