Not that I understand this clearly, much less being able to advice (while finding this horribly dangerous to be implemented by unqualified people).

And the reference to the additional DC circuit is even more misleading to me.

I downloaded the manual in the reference given by the OP. It seems to me he is trying to implement this (I could be wrong): If suggested I offer to delete whatever is wrong here.

 

I downloaded the manual in the reference given by the OP. It seems to me he is trying to implement this (I could be wrong): If suggested I offer to delete whatever is wrong here.View attachment 97709

Correct - this is one of the products I found which supported my belief that this is possible. The Lightwave RF product powers itself only from the unswitched and switched 230V phase conductor - no neutral conductor.

My design partly aims to replicate the function of the Lightwave RF switch (remote operation of a lighting circuit without rewiring the circuit) however I will be performing additional functions (sensoring, monitoring & general processing of information) within the DC circuit.

 

I have re-read this post and I must be missing something. You say that you want a little power, whether the switch is on or not. If you put a small transformer in parallel(across the power legs), before the switch...you got it. Can anyone here explain, how putting the transformer in series, solves this problem?

 

I have re-read this post and I must be missing something. You say that you want a little power, whether the switch is on or not. If you put a small transformer in parallel(across the power legs), before the switch...you got it. Can anyone here explain, how putting the transformer in series, solves this problem?

Bear with me but the reason that it is in series as I was trying to make the circuit work without pulling in a neutral conductor to the location where my circuit is (behind light switch). In the UK we don't have a neutral conductor here as part of our lighting circuits.

This was one of my initial queries.

Refer to the first schematic ScottWang uploaded from my other post detailing the intent.

I'm not sure I follow 100% what you mean...I think ScottWangs modified schematic is what you are referring to. If not could you upload a quick sketch?

I have also considered harvesting energy using a current transformer rather than pulling power through an isolating transformer but I'm not able to harvest enough power to drive my circuit.

Does this help clarify my requirement?

 

Use a center tap transformer in post #15.

 

Trying to power the MCU directly from the AC line (open switch) is contrary to the rules of this web site...

 

You saying that you just treated the primary coil of transformer like as a resistance, how is the spec of transformer?

And what is inside of the current limiter (V/A), any information of specification?

 

Trying to power the MCU directly from the AC line (open switch) is contrary to the rules of this web site...

That is not my intention.

The AC on the secondary of the transformer will be rectified to DC which will then feed the MCU.

 

You saying that you just treated the primary coil of transformer like as a resistance, how is the spec of transformer?

And what is inside of the current limiter (V/A), any information of specification?

ScottWang - I propose to use the Block VB 1.5/1/6 (230Vac primary / 1 x 6Vac secondary delivering 1.5VA) as per the attached datasheet. I may likely select a lower power version.

As for the current limiter, I have no specification. This was a question as to the feasibility of restricting the current in the circuit - is it possible to restrict the current on an AC circuit? and if so how can it be done. I will consume approx 100mA on my circuit downstream of the Block transformer.

 

Use a center tap transformer in post #15.

My circuit cannot adopt the schematic in post no. 15, if this is the only way to do it then I have no circuit and I am at a dead end. I can buy something off the shelf doing what I need to do which operates as per the schematic in post no. 15.

I am pushing for a solution to the schematic in post no. 13 which will make my circuit viable.

 

I am sorry my friend, I don't want anything to do with that circuit. Especially at 220V.

Good luck and please review what 220 V can do to a thin bag of salt water.

 

Lesney,
Why dont you put your transformer primary across the switch terminals and using the bulb as the Neutral, see what voltage you will get on the secondary side, and you will then know if it works, then you can stop asking stupid questions.

 

BR-549 & Dodgydave thanks for your help so far.

Perhaps the reason that I am asking stupid questions is because I am not kidding myself that I am as informed or as experienced as others out there therefore I do not know if the questions I am asking are stupid until I am educated otherwise.

It is for precisely this reason - and that I do know the dangers of working with electricity - that I am throwing these ideas around as something might come out of the discussion which sticks and provides me with a way forward. Until that point comes I'll continue to ask stupid questions unknowingly and I will appreciate any honest and helpful advice or thoughts which come my way as a result of this post.

 

ScottWang - I propose to use the Block VB 1.5/1/6 (230Vac primary / 1 x 6Vac secondary delivering 1.5VA) as per the attached datasheet. I may likely select a lower power version.

As for the current limiter, I have no specification. This was a question as to the feasibility of restricting the current in the circuit - is it possible to restrict the current on an AC circuit? and if so how can it be done. I will consume approx 100mA on my circuit downstream of the Block transformer.

If the power of bulb is AC230V and the transformer is the same then you have two loads in series, normally we don't use that way, and it should be powered by the circuit that I modified, and also you need to know, the forum does not allowed to use the uC or low power DC device with the mains, if you want to adjust the AC current then you can using SSR or the photo diac and triac, and the power of led(photo diac) and the power of control device can be supply by the secondary coil of transformer.

 

If the power of bulb is AC230V and the transformer is the same then you have two loads in series, normally we don't use that way, and it should be powered by the circuit that I modified.

Ok - thanks, I think I have had enough feedback to know that my initial circuit is not conventional and I'll likely drop it and look at other options.

and also you need to know, the forum does not allowed to use the uC or low power DC device with the mains, if you want to adjust the AC current then you can using SSR or the photo diac and triac, and the power of led(photo diac) and the power of control device can be supply by the secondary coil of transformer.

Can I ask why this is not allowed to be discussed in the forum? is the use of a uC or low power DC device powered by the mains via an AC/DC converter dangerous?...and thanks for the link.

 

Ok - thanks, I think I have had enough feedback to know that my initial circuit is not conventional and I'll likely drop it and look at other options.

Can I ask why this is not allowed to be discussed in the forum? is the use of a uC or low power DC device powered by the mains via an AC/DC converter dangerous?...and thanks for the link.

Using AC/DC converter is ok, what I said is the DC device connected with the mains(as AC110V/AC220V), if the power of current limiter is a low power device and used the transformerless power supply then it is not allowed to discuss and that is for the safety issue.

--------------------
User Agreement.

6. Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in Your thread being closed without question:

• Any kind of over-unity devices and systems
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

http://www.allaboutcircuits.com/user-agreement/

 

Because it is part of our rule set here. It is not safe, nor can it be made so.

6. Restricted topics. The following topics are regularly raised and however are considered “off-topic” at all times and will results in Your thread being closed without question:

• Any kind of over-unity devices and systems
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

This can be found in our Terms of Service (ToS)

If you buy a AC/DC converter the manufacturer takes responsibility, and there is a good chance it has a high frequency circuit and a toriod transformer.

We do not allow transformerless power supplies on this site, period.

Since Scott was here first I will leave it to him to decide to lock this thread or not, My recommendation is that it is a ToS violation.

 

Using AC/DC converter is ok, what I said is the DC device connected with the mains(as AC110V/AC220V), if the power of current limiter is a low power device and used the transformerless power supply then it is not allowed to discuss and that is for the safety issue.

Ok - it was always my intention to use an AC/DC converter.

Thanks also for the link to the ToS, I see how interpretation of my comments could be in violation so I'm happy for you to decide whether or not to close the thread.

As I mentioned previously I am here to seek help and in no way looking to implement something unsafe - hence my questions.

 

Three thoughts on this:
1) Since there appear to be numerous commercial examples of this, there must be a way to do it properly.

2) These are potentially dangerous things to play with, and I'm skeptical at this point that the TS is qualified to take chances with them. I'd recommend that the TS find a qualified engineer for help before proceeding with this (which is probably why the TS is here in the first place.)

3) This really doesn't look to me like a TOS violation to me. The TS has wanted transformer isolation to power the mcu from from the very start. So the only question is how the mcu will control the mains-powered lighting output. This can be safely implemented with opto-isolation, so there needn't be a problem.

I for one am very interested in knowing how those existing products get the power they need without a neutral. This is a fascinating question.

I'm also still fairly new at all of this - I definitely know better than to attempt a project like this myself, and my interpretations above could be off base as well due to my inexperience.

 

The AC supply is intermittent

The problem is quite difficult and depending on the nature of the intermittency may not have a solution.

AC/DC conversion is easy and there are many solutions. Energy storage, particularly in DC, is not difficult as well. But if you don't know the nature of the intermittency, there is no assurance that there will always be DC available to your circuitry.

If I were you, i would try to figure out a way to avail the AC source permanently; For example, always turn on the AC switch and establish another switch to turn on / off the light.

Other than that, do AC/DC conversion and use it to charge the battery. Then use the battery to power a DC/DC converter for your circuitry.