I have a vague concept here, but none of the details. I'll try to explain and see if this helps.

I've heard too many different descriptions of the loads to be clear on what they are. LED, lamp, room lights, I'm not sure, so I'll just call it load A and load B.

Let's say load A is the one with the remote control, and the one which can essentially take the power away, only when it needs it.

So, run one leg of the power to load A through a current transformer as a means of detecting when it's drawing power. With an appropriate burden resistor and an RC filter, we can easily get a simple low voltage signal indicating whether or not load A is drawing power.

Now we run that low voltage signal through a BJT or MOSFET (maybe two, including a required logic inversion) which controls a relay that controls power to load B.

With this setup, you'd get the following:

• Load B can be on any time (presumably still controlled with some manual switch as well,) except...
• Any time load A is turned on (via its remote control,) the logic circuit disconnects power from load B so that only load A is on.
• If load A is turned back off, power is automatically available to load B again.
• Essentially load A is in control. It always takes priority.

I don't see any way for both devices to be in control, as a few of the posts above seem to suggest. However, if one load can be the master, it should be possible to make a circuit that defeats the other load any time the master load is active.

This is far more complicated than the simple DPDT relay/switch ideas others have shared, but if it turns out that the remote switching can't be tapped into, this might get the job done.

Wow yes have to google everything but thankyou for your help!

 

I have a vague concept here, but none of the details. I'll try to explain and see if this helps.

I've heard too many different descriptions of the loads to be clear on what they are. LED, lamp, room lights, I'm not sure, so I'll just call it load A and load B.

Let's say load A is the one with the remote control, and the one which can essentially take the power away, only when it needs it.

So, run one leg of the power to load A through a current transformer as a means of detecting when it's drawing power. With an appropriate burden resistor and an RC filter, we can easily get a simple low voltage signal indicating whether or not load A is drawing power.

Now we run that low voltage signal through a BJT or MOSFET (maybe two, including a required logic inversion) which controls a relay that controls power to load B.

With this setup, you'd get the following:

• Load B can be on any time (presumably still controlled with some manual switch as well,) except...
• Any time load A is turned on (via its remote control,) the logic circuit disconnects power from load B so that only load A is on.
• If load A is turned back off, power is automatically available to load B again.
• Essentially load A is in control. It always takes priority.

I don't see any way for both devices to be in control, as a few of the posts above seem to suggest. However, if one load can be the master, it should be possible to make a circuit that defeats the other load any time the master load is active.

This is far more complicated than the simple DPDT relay/switch ideas others have shared, but if it turns out that the remote switching can't be tapped into, this might get the job done.

That is exactly what I would want could you help me understand it (explain it again in simple language or something) sorry but thats a bit over my level...

 

That is exactly what I would want could you help me understand it (explain it again in simple language or something) sorry but thats a bit over my level...

I'll try to sketch out a schematic to make sure I've got the idea clear in my head before I describe any more detail.

It occurs to me that we can probably buffer the CT input, invert the signal, and maybe even drive the relay coil (if we're lucky) with just one Schmitt trigger inverter IC. If that turns out to be true, it'll be a pretty simple circuit. Fingers crossed!

Can you tell me how much power the remote controlled lights draw? If you can tell me the current (amps) that would be ideal - if not, tell me the wattage and voltage. I need at least a ballpark estimate in order to choose the CT and burden resistor values.

 

I'll try to sketch out a schematic to make sure I've got the idea clear in my head before I describe any more detail.

It occurs to me that we can probably buffer the CT input, invert the signal, and maybe even drive the relay coil (if we're lucky) with just one Schmitt trigger inverter IC. If that turns out to be true, it'll be a pretty simple circuit. Fingers crossed!

Can you tell me how much power the remote controlled lights draw? If you can tell me the current (amps) that would be ideal - if not, tell me the wattage and voltage. I need at least a ballpark estimate in order to choose the CT and burden resistor values.

Wow youre the best thank you so much, the Lamps draw around 250w im not sure about the voltage and watage of the other lamp it js pretty high though (betweed 250 and 500w). Thank you so much I hope th circuit will be very simple and thank you for your help!

 

Wow youre the best thank you so much, the Lamps draw around 250w im not sure about the voltage and watage of the other lamp it js pretty high though (betweed 250 and 500w). Thank you so much I hope th circuit will be very simple and thank you for your help!

Sounds good. Just to double check: both lamps are running on AC, around 220V?

 

Sounds good. Just to double check: both lamps are running on AC, around 220V?

No the one lamp is an old street lamp i think it is running DC but i can buy an inverter

 

No the one lamp is an old street lamp i think it is running DC but i can buy an inverter

Shouldn't be necessary. It does matter which lamp is which though.

In the scheme I've imagined one lamp is the master. When you turn it on, it automatically turns the other one off, and when you turn it back off, the other one can be on again. The master overrides the other one, sort of "stealing" its power if you want to think of it that way. There can only be one master.

Which one should be the master? Is it the one that runs on AC, or the old street lamp? The circuit I described earlier is based on the master running on AC. It doesn't really care what the other lamp uses, as long as we pick a suitable relay for the output stage.

If you want the master to be the street lamp, then you need to find out for sure whether it's AC or DC and at what voltage - that would require a different approach than what I described earlier, but should also be possible.

 

Shouldn't be necessary. It does matter which lamp is which though.

In the scheme I've imagined one lamp is the master. When you turn it on, it automatically turns the other one off, and when you turn it back off, the other one can be on again. The master overrides the other one, sort of "stealing" its power if you want to think of it that way. There can only be one master.

Which one should be the master? Is it the one that runs on AC, or the old street lamp? The circuit I described earlier is based on the master running on AC. It doesn't really care what the other lamp uses, as long as we pick a suitable relay for the output stage.

If you want the master to be the street lamp, then you need to find out for sure whether it's AC or DC and at what voltage - that would require a different approach than what I described earlier, but should also be possible.

Thank you for your Ideas, im currently not home so it will take a couple of days to find the voltage of the street lamp, i would want that to be the master
Thanks again
Ralf

 

Ok, just to get my thoughts clear on this, I've worked up a schematic and simulation. This is based on a lot of assumptions:

1. The "Master" lamp (Lamp1 in the attached schematic) runs on AC mains power.
2. The "Master," Lamp1, draws somewhere around 1 amp (~240W at 240V)
3. There is already a 12VDC power source available - if not, you'd need to get a DC power adapter of some sort. It wouldn't necessarily have to be 12V, but that seems like a convenient value, since there are many relays available with 12V coils.
4. The relay coil can be driven directly from the output of a Hex inverter - I believe this will be a manageable requirement, but I haven't actually checked yet. Right now, all I've done is play with the simulator to get my logic/concepts right. If I'm wrong on this part, it's no big deal - simply adding a transistor of some sort between the inverters and the output relay is easy.

If the Master lamp doesn't run on AC mains, then this circuit would be fundamentally wrong, and quite a bit would have to change. If any of the other assumptions are wrong, it's not a deal-breaker, and we'd just have to adjust component values or add one or two more small components. This circuit looks more complicated than it really is.

In operation, one side of the power to Lamp1 runs through the donut-hole in the current transformer. Any time Lamp1 is turned on, the circuit senses the current flow and applies power to the output relay, which opens the NC contacts, turning Lamp2 off.

There are a few simple passive components, a Hex inverter, a relay, and the key component is a current transformer.

I've only worked with current transformers a little bit, but one I've used which I think would work in this applications is:
http://www.crmagnetics.com/high-fre...rs/wire-lead/voltage-output/solid-core/cr8448
https://www.digikey.com/products/en?keywords=CR8448-2000-ND

Hex inverter would be something like this:
https://www.digikey.com/product-detail/en/texas-instruments/CD40106BE/296-3503-5-ND/376602

Relays might be something like one of these:
https://www.digikey.com/products/en...ColumnSort=1000011&page=1&stock=1&pageSize=25