Hi all. Just found this forum/website while researching my predicament for the past few weeks...hope someone can help.
I'm switching alarm systems -- another wireless type that I'm trying to hack to use my existing wired sensors instead. I did this successfully with my old (current) system, by connecting the wired sensor wires to the wireless sensor's reed switch. So, instead of a magnet attached to my door activating the wireless sensor's reed switch on the door frame, I let my wired sensor on the door shunt the reed switch (mounted in my utility closet at the alarm box) which then triggers the alarm signal -- on an open condition. Effectively, I'm just using the wireless sensor to transmit the door action to the alarm base station.
All well & good with the current system, but the new system doesn't like the resistance (about 6 ohms) on my sensor wiring (multiple doors and windows wired in series) and apparently doesn't distinguish that from an open condition.
So, I inserted a Sainsmart 5v relay board into the mix, to handle the switching of the wireless sensor, with the relays triggered/energized via the wired sensor action. This works, but with two problems: I don't like having mechanical relays in this circuit, and I especially don't like having the relay coil energized all the time a door is closed -- or a window is open for that matter. But I have a few constraints. The wireless sensor is basically a black box to me -- I have no idea what the circuit looks like that contains the reed switch that I'm shunting, but it seems to trigger on the trailing edge, i.e., it only "fires" when it's been closed and then opened. For this reason, I'm not sure I could connect it directly to a MOSFET with its voltage and current flow.
Not to mention, these relays I'm using require a "LOW" (0, or ground) to trigger, and all I've got is a sensor circuit that is either closed or open -- and open doesn't translate into LOW very easily.
OK... I struggled with how to describe this problem with enough detail to make it understood, but without too much that you don't want to read it (TL,DR?), and you could say I've failed at both ends, but here's the bottom line:
When my series-wired sensors' circuit is closed: I need the wireless sensor's reed switched to be shunted (shorted);
When that wired circuit opens: I need to unshunt/unshort/open the reed switch circuit.
And...I'd prefer mechanical relays were not involved. (also prefer not to have to insert a microcontroller into the mix - has to be an easier way, right?)
And...the wireless sensor/reed switch circuit is a black box to me.
Any ideas/suggestions will be greatly appreciated. Have been head-banging on this for far too long.
I'm switching alarm systems -- another wireless type that I'm trying to hack to use my existing wired sensors instead. I did this successfully with my old (current) system, by connecting the wired sensor wires to the wireless sensor's reed switch. So, instead of a magnet attached to my door activating the wireless sensor's reed switch on the door frame, I let my wired sensor on the door shunt the reed switch (mounted in my utility closet at the alarm box) which then triggers the alarm signal -- on an open condition. Effectively, I'm just using the wireless sensor to transmit the door action to the alarm base station.
All well & good with the current system, but the new system doesn't like the resistance (about 6 ohms) on my sensor wiring (multiple doors and windows wired in series) and apparently doesn't distinguish that from an open condition.
So, I inserted a Sainsmart 5v relay board into the mix, to handle the switching of the wireless sensor, with the relays triggered/energized via the wired sensor action. This works, but with two problems: I don't like having mechanical relays in this circuit, and I especially don't like having the relay coil energized all the time a door is closed -- or a window is open for that matter. But I have a few constraints. The wireless sensor is basically a black box to me -- I have no idea what the circuit looks like that contains the reed switch that I'm shunting, but it seems to trigger on the trailing edge, i.e., it only "fires" when it's been closed and then opened. For this reason, I'm not sure I could connect it directly to a MOSFET with its voltage and current flow.
Not to mention, these relays I'm using require a "LOW" (0, or ground) to trigger, and all I've got is a sensor circuit that is either closed or open -- and open doesn't translate into LOW very easily.
OK... I struggled with how to describe this problem with enough detail to make it understood, but without too much that you don't want to read it (TL,DR?), and you could say I've failed at both ends, but here's the bottom line:
When my series-wired sensors' circuit is closed: I need the wireless sensor's reed switched to be shunted (shorted);
When that wired circuit opens: I need to unshunt/unshort/open the reed switch circuit.
And...I'd prefer mechanical relays were not involved. (also prefer not to have to insert a microcontroller into the mix - has to be an easier way, right?)
And...the wireless sensor/reed switch circuit is a black box to me.
Any ideas/suggestions will be greatly appreciated. Have been head-banging on this for far too long.