I have an IR sensor and wish to extend this to 2 IR sensors using the same 4 wires. If I install a new sensor with its own wiring it means running the cables all around the building which is almost impossible as the installation is complete and hidden.
There is a +12n and ground input (same for all sensors) plus an alarm line and a common. All alarms connect to the common. This just leaves the signal line.
I assume that this is held high for 'normal' or pulled low for 'alarm' just in case the wires are cut.
If I connect a second sensor then both sensors will send a high signal. If one sensor detects an intrusion it will go low. Now the 2 inputs are competing so how or what simple circuit can I use if either input line goes low the output will also go low.
Access to parts is limited here in the Pacific and so I have resistors, capacitors, op amps, comparators and a few transistors to build it from.
Any ideas as a direction to study would be invaluable.
Qbits
There is a +12n and ground input (same for all sensors) plus an alarm line and a common. All alarms connect to the common. This just leaves the signal line.
I assume that this is held high for 'normal' or pulled low for 'alarm' just in case the wires are cut.
If I connect a second sensor then both sensors will send a high signal. If one sensor detects an intrusion it will go low. Now the 2 inputs are competing so how or what simple circuit can I use if either input line goes low the output will also go low.
Access to parts is limited here in the Pacific and so I have resistors, capacitors, op amps, comparators and a few transistors to build it from.
Any ideas as a direction to study would be invaluable.
Qbits
