FreeBSD and controlling an alarm via relay

[Achilleas Mantzios]

another thing that puzzles me is power.
This board : http://www.ebay.co.uk/itm/USB-Eight-Channel-Relay-Board-RS232-=
Serial-Controlled-/110710333092?pt=3DUK_BOI_Electrical_Components_Supplies_=
ET&hash=3Ditem19c6d99ea4
needs VDC 12V supply=20
while this one : http://www.ebay.co.uk/itm/USB-Four-4-Relay-Module-Board-Ho=
me-Automation-/180646300804?pt=3DLH_DefaultDomain_0&hash=3Ditem2a0f5bcc84
is self powered from USB.

batteries do not come cheap, and having an extra AC/DC adaptor is not very =
good either ...

another thing is the relay parameters, i see various figures :
Relay parameters: 5V / 72mA, 15A/24VDC (120VAC), 10A/250VAC or
Each switch 12VDC/15A or 240VAC/10A or
Open (No) and Closed (NC) Contacts rated for voltages: 12VDC/15A; 24VDC/15A=
; 125VAC/15A; 250VAC/10A

my specific application i want to drive is this wireless xmitter :
http://www.visonic.com/Data/Uploads/MCT_100_Installer_Guide_English_DE2241U=
=2Epdf
Should i assume my device that i want my relay to control will have voltage=
 of 3V?

for which Voltage/Ampere figures should i opt? are those figures crucial?

thanx a lot

=CE=A3=CF=84=CE=B9=CF=82 Wednesday 06 July 2011 11:03:14 =CE=BF/=CE=B7 Ian =
Smith =CE=AD=CE=B3=CF=81=CE=B1=CF=88=CE=B5:
> On Tue, 5 Jul 2011, Achilleas Mantzios wrote:
>  > =FF=FF=FF=FF=FF=FF=FF=FF Tuesday 05 July 2011 16:10:59 =FF=FF=FF=FF=FF=
=FF=FF=FF=FF=FF=FF=FF=FF=FF:
>  > > On Mon, 4 Jul 2011, Achilleas Mantzios wrote:
>  > >=20
>  > > [snip]
>  > >=20
>  > > > I was thinking of some relay board (instead of the old modem),=20
>  > > > possibly ethernet controlled
>  > >=20
>  > > This box has relays and GPIO available via ethernet. It's probably=20
>  > > overkill for your application, but it's well made and easy to use:
>  > >=20
>  > > http://www.extron.com/product/product.aspx?id=3Dipltcr48&s=3D0
>  > >=20
>  >=20
>  > That is too big for my application, thanx anyway.
>  > Most probably i'll go for something cheaper like this one=20
>  > http://www.ebay.co.uk/itm/USB-Eight-Channel-Relay-Board-RS232-Serial-C=
ontrolled-/110710346488?pt=3DUK_BOI_Electrical_Components_Supplies_ET&hash=
=3Ditem19c6d9d2f8
>=20
> These look quite well designed and built to me, reasonably priced new,=20
> but check out the/a source site [1] for various models, 1- and 4-relay=20
> boards too, or if you prefer, RS-232 serial rather than USB interface=20
> for the 8-relay boards.  There's also a simple parallel port to 8 TTL=20
> outputs board (hi Tim!) and various other stuff.  I'm tempted myself.
>=20
> [1] http://sigma-shop.com/category/4/relay-boards.html
> [2] http://www.sigma-shop.com/page/12/manuals.html
>=20
>  > Could i use the ucom driver to talk to the USB device like a normal se=
rial device, via /dev/cua*** ?
>  > The above link says one needs to talk to the relay with:
>  > 8 Data, 1 Stop, No Parity,Baud rate : 9600
>  > and the commands look like:
>  > FF 01 00 (HEX)=20
>  > or=20
>  > 255 1 0 (DEC)
>  >=20
>  > could i be able to specify those over ucom?=20
>=20
> If so, great.  If not and you have a serial port, the code will be the=20
> same anyway, except the port used.  I grabbed most of the manuals from=20
> [2] and found the Linux software examples are all this one:
>=20
> =3D=3D=3D=3D=3D=3D=3D
> Linux :
> The USB-serial device is automatically detected and mapped to /dev/
> ttyUSB0 (or USB1 in case there is already a similar device).
> My test script: (Thanks Julian!)
> --------------------------------------------------------
> # cat relay.sh
> while true
> do
> echo -e "\xFF\x00\x00" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x00\x01" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x00\x00" > /dev/ttyUSB0 ; sleep .1
> [..]
> echo -e "\xFF\x01\x01" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x02\x01" > /dev/ttyUSB0 ; sleep .1
> [..]
> echo -e "\xFF\x07\x01" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x08\x01" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x01\x00" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x02\x00" > /dev/ttyUSB0 ; sleep .1
> [..]
> echo -e "\xFF\x07\x00" > /dev/ttyUSB0 ; sleep .1
> echo -e "\xFF\x08\x00" > /dev/ttyUSB0 ; sleep .1
> =3D=3D=3D=3D=3D=3D=3D
>=20
> If using sh[1] you might need to use \0377 instead of \xFF
>=20
>  > do you know any application, perl library, utility or just a guide for=
 standard C serial port programming?
>=20
> Anything that can write bytes to a serial port - perl's overqualified :)
>=20
> [..]
>=20
> cheers, Ian



=2D-=20
Achilleas Mantzios