Technical Help required ....... please!

[Alan Maggs]

Good Morning

I am trying to set up small custom call system, for a temporary application, which will need to operate until a central upgrade is completed.

I need to have individual over-door-LED's working simultaneously with a central sounder. The Lights above the door are triggered by a remote transmitter/receiver combination. I have tried connecting the sounder in circuit which results in ALL the over-door-lights coming on with the activation of any of the room receivers.
It is most important that the care-giver knows from which room the signal was generated.
It is not practical to have individual sounders for each room.

Is there a possible solution?

 

[rjenkinsgb]

Add a series diode from each receiver output to the common "sounder" feed wire.

If the sounder takes less than one amp, a common 1N4000 series diode such as a 1N4002 or 1N4007 should be fine; connect the anode to the receiver and cathode (banded end) to the sounder feed.

The diodes prevent a "reverse flow" back from the sounder connection to any other lamp.

ps. 12V power would normally be labelled as +12V and 0V, using -12 could be seen as a 12-0-12 system.

 

[AnalogKid]

What is the output of the receiver? Relay contacts / transistor switch / optical coupler / other? If a relay, SPST, SPDT, etc?

Is the "-12V" line actually the power supply ground? If not, where is ground in the circuit?

Specs on the sounder

Specs on the ODL. BTW, ODL is not an industry standard term in electronic circuit design. I know what you mean, but others will not.

ak

 

[Alan Maggs]

Thanks for the feedback so far.... much appreciated.

Yes, the -12V should be indicated as the power supply ground.
The sounder is a integrated device, which has an adjustable volume control, and an operating voltage range of between 9-28V DC. Current Consumption 5-36mA (tone dependent)
The wireless receiver is connected with the N/O relay contact closing the ground circuit on activation. (Latching)
The Over Door lamp consists of 4 LED's which illuminate on activation of the local wireless receiver (12V).

I hope I have provided enough information.. I will source some diodes in the mean time.

 

[rjenkinsgb]

That's all fine, the diode should do the trick.

 

[Alan Maggs]

Thank you.