Hi,
I'm trying to wire a security device that would keep a switch A open when ignition is off, keep it open when the ignition is on then close it and keep it closed when a control switch is pushed then released. When the ignition is cut the switch A would open again.
The different states would be as follows:
1. Ignition off: switch A open
2. Ignition on: switch A open
3. Ignition on + control switch C closed: switch A closed
4. Ignition on + control switch C released: switch A closed
5. Ignition off: switch A open
Reportedly it would be possible to do this with a SPNO relay (e.g. Maplin ref N02AW)
http://www.maplin.co.uk/Search.aspx?cri ... ce=15&SD=Y
As anybody tried this or would know how to do it?
Regards,
Pascal
relay operated security switch
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Willie
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relay
Position 3: Ign on +control switch Closed: Control SW live feed is taken
from the side of the ignition switch which is only live when it is ON. This would operate the relay. The relay would have contacts wired to supply
Live feed to itself thus keeping it operated when the Control SW was released. Provided that this live feed was supplied by the ignition switch only in the ON position the relay would remain operated until the
ignition was turned off. This 'self operatiing ' condition would used one
set of the relay contacts but you would have at least one other pair to
play with.
from the side of the ignition switch which is only live when it is ON. This would operate the relay. The relay would have contacts wired to supply
Live feed to itself thus keeping it operated when the Control SW was released. Provided that this live feed was supplied by the ignition switch only in the ON position the relay would remain operated until the
ignition was turned off. This 'self operatiing ' condition would used one
set of the relay contacts but you would have at least one other pair to
play with.
Willie
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Rob_Jennings
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It can be done with a single pole normally open or a double throw relay.
diagram below shows how.
'supply' is from the switched ignition supply
'ground' and 'output' are obvious
BUT if you draw too much current on the output you may cause the relay to turn off, the switch must be able to handle the current required by the output as for a brief period it will carry that current.
hope that helps
diagram below shows how.
'supply' is from the switched ignition supply
'ground' and 'output' are obvious
BUT if you draw too much current on the output you may cause the relay to turn off, the switch must be able to handle the current required by the output as for a brief period it will carry that current.
hope that helps
Rob
Cars: Lizzy 1970 Morris Minor Traveller and Noah 1969 Morris Mini Traveller
Cars: Lizzy 1970 Morris Minor Traveller and Noah 1969 Morris Mini Traveller
I just ran across this page, http://www.the12volt.com/relays/page2.asp . It has some interesting ideas for "hidden" security.