How to shield a live wire at 240V ?

[_q12x_]

I've updated the original sketch circuit. I discovered a little error there so I redrawn it all, I had it in plan to do it, so now I did it. The error was those 2 resistors how they linked to the pins. Now is corrected and is exactly as in my real circuit. If you want to make it like mine.

You can check it here: Q20201219 Led Wings Projekt Circuit by q12a on DeviantArt - https://www.deviantart.com/q12a/art/Q20201219-Led-Wings-Projekt-Circuit-864540519 Is the same link as before but I changed the image with this updated version.

 

[_q12x_]

another update:
I made a test for the LM3914, then I made a new test on the workbench and on the wall.
I made a manual switching module with a pot and is working fine.
I was afraid of further interference on the wall, but is normal now with the pot.
I am curious what other sensing modules you can think I should try.
Please enumerate all that you have in mind. I have already mentioned myself a few, in the movie. I don't care for originality but I care for quantity this time. So, go nuts.
Warning, this is a lengthy movie, 23m.

 

[marconi]

Buna dimineata. Greetings from London. Your youTube clip was very clear and confirms all is well when the sensing circuit is disconnected - but I await confirmation that it continues to work 'perfectly' when you remove the metal back-plate - an important check.

You have also confirmed your circuit only draws about 60mA. Does this figure include the current for the two relays? Perhaps you could just tell me the resistance of the coils of these relays and I will work out how much current they draw?

When pin 5 of the LM3914 is not connected to anything it will be at an indeterminate or floating potential with respect to ground - or in other words a random voltage - because there are leakage currents to pin 5 from within the integrated circuit. In electronic circuits one must ensure that input pins are never left floating because such an electrical input is random and will affect how the circuit works. We connect them to 0V or 5V.(VDD/VCC).

LED1 is so bright compared to LEDs 2 to 10 because the LED current is set by resistor R1 and R2 at pin 7 - see figure 1 of the datasheet which says the LED current is 12.5/R1. Pin 1 only has one LED connected to it whereas the others have three LEDs; thus LEDs 2-10 have a third of the current flowing through them of LED1. We can adjust the brightness of LED1 to match that to LEDs 2-10 by adding a suitable resistor in series with it - you can work out what resistance value is required or I can help you with that.

https://www.ti.com/lit/ds/symlink/lm3914.pdf

I must express some mild irritation with you. I have asked several times if you would check that the leads of the MOSFET 2N7002 are actually connected correctly in the sensing circuit. It should be connected as in my attached diagram. If it is wired in wrongly that could explain why in one of your youtube clips the potentiometer had no effect on the performance of the sensor circuit.

I will construct your sensing circuit to see how it performs. We can work together to see if we can make it work reliably. If we cannot I have a sensor idea which uses infra red reflection of the hand. My components for your sensor and mine were ordered last Saturday so they should arrive soon.

Regards

Marconi

 

[_q12x_]

Buna dimineata de asemeni. Your romanian is perfect. Good morning from Romania as well. I didn't slept all night, and now im a bit tired.
I am happy you watched that last video and seen the updates so far.
I already explained the relay part:
"When all is Off, is measuring 20mA. When all is On, is 60mA. But when I keep my hand over the sensing circuit to really keep everything ON including relay1, it goes to 100mA, and after I raise my hand, it goes back to 60mA."
I also have the data about the relays, no need for calculations. Works at 5V, draws 30-40mA, and coil resistance is 128R. But in my wings circuit they draw around 30mA. Im not sure why... probably they are limited by the transistors in the relay driver circuit(the little ones with orange and blue leds on them). Is my best guess.

In electronic circuits one must ensure that input pins are never left floating because such an electrical input is random and will affect how the circuit works. We connect them to 0V or 5V.(VDD/VCC).

That is a very interesting piece of information. It is true for PIC's as well? where you have many inputs/outputs pins? The effect is only visible when I touch pin5 on lm3914, and not when is free "in the air' as I call it. But I get your point, to avoid stupid contacts of any kinds, you link it to a rail. Im not sure is a general truth, but it might be fine for many IC's.

Led 1 and 10 are the least of my concerns at this point. They will be dealt with in the very end. As you probably feel me and observed me, I dont like to do simple things, but the complex ones that I am attracted. So, in my mind, I must clear the general fog and then smell the flowers.

Yes 2n7002 is mounted correctly. I pay special attention and double check when I mount my transistors. Im also very careful for a very simple reason: I don't like to make the circuit again from scratch. So im careful from the start.



I must also share this old sketch of mine:

It means the area of effect of the sensor, how I imagine it should work. That is a crude representation, but it tells the idea well. Of course I want gradual opening of the leds, and also a considerable distance. Ideally the distance to be customized. That is done from the antena alone, from my discoveries so far, with this sensing circuit in particular.
As I said in the movie, I will use IR for a remote control. So I will not interfere it with my sensor. Or should I? If I am making an IR sensing sensor? But as how much -------- I got from this sensing circuit, the IR one should be easy in comparison. I already have a very interesting module I will most probably use. At least I will test it first then I will consider to use. We'll see. I'll wait for your ideas first.
Thank you for your reply. Have a nice day, today.

 

[marconi]

The reason why you have an increasingly small distance between illumination of the LEDs as the hand approaches the sensor is that the sensor has a variation in voltage output (V5) with d as I have shown in my first diagram. However, the LM3914 has a linear relationship between V5 and LED illumination interval because all the voltage steps along the resistor ladder (the 3 resistors R across the 3Volts Zener diode) to the comparators (second image) are the same - 1V in my example.

I could not buy LM3914 ics so I have bought discrete comparator chips which means I can adjust the voltages to each of them to correct for the Voltage/distance output of the sensor circuit to achieve the 'customisation' of wing illumination you mentioned in one of your earlier youtube clips.

 

[_q12x_]

What opamp are you using for your comparator? I have myself a bunch of uA741 in my stock. Unfortunatly I dont have the newest models with rail to rail options. I may try to get in sinc with your tests, using my opamp, if you also have uA741. i'm also curious how you will use it with only +5v and 0V. Usually an opamp uses +5V,0V and -5V.

 

[marconi]

https://www.ti.com/lit/ds/symlink/lm339.pdf?ts=1611642239603&ref_url=https%3A%2F%2Fwww.google.com%2F

I will look in my drawers to see if I have some 741s too so we can use the same opamps.

 

[marconi]

Buna seara la un sicriu roman! Just a quick message - because as usual I am cooking and sitting down with my wife for an evening in front of the television - my electronic components have arrived! I will start to construct your sensing circuit tomorrow morning.

I think we should add a peak detector and low pass filter between the sensing circuit and pin 5 of the LM3914. Something like the circuit I have sketched in the attachment. Most of the 'reliable' pick up by the antenna of of signals from the hand will be due to the mains wiring since it is energised all the time, so a low pass filter which reduces other signals which are picked up beyond 50/60Hz (what is Romanian mains frequency?) will make a difference. No sums done yet by me on component values. You could make a start if you wish. Assume the frequencies beyond 1/2piCR.....

https://www.electronics-tutorials.ws/filter/filter_2.html

 

[marconi]

We will reverse the order of the two circuits I mentioned ie low pass filter and then peak detector.....so that we only find the peak of the 50/60Hz signal. You understand why I have reversed the two circuits?

 

[_q12x_]

Buna seara la un sicriu roman!

Did I offend you in any way so far? Then don't do it to me either. If you dont think im at your level and im just a joke, please dont speak to me and I will also stop writing here. Your intentions are many from what I can see. Why do you call me a romanian coffin ? It is not funny and you deserve plenty of my negative response right now. I will abstain though. Your "familiarity" is starting to become insulting. Please think before you write anything to me. Im not here to dick around. If your romanians friends there are not respecting their compatriots, then that should not be a lesson for you to follow. Usually ignorance is a good remedy for that. I'll give you one more chance to be normal. If you will still continue to "be funny", then I will have to say goodby to individuals like you.
Now... to respond to your question, I am not that familiar with low pass filters or peak detectors. I never use them or feel the use of them.

 

[marconi]

I entered 'good evening to a Romanian boffin' in to google translate from English to Romanian:

https://translate.google.com/?sl=auto&tl=ro&text=good evening to a romanian boffin&op=translate&hl=en

and what I copied and pasted in my message #48 is what appeared: 'buna seara la un sicriu roman'.

Try it yourself please.

I leave it to you, to do the research in order to comprehend what I as someone speaking English in a technical forum intended to say but clearly and mistakenly did not say in Romanian: I intended to address you in a most complimentary way in comparing you to a boffin.

 

[_q12x_]

Thank you for your response and reparation. You see how a single word matters? The translator is not perfect. I checked your link and indeed it translates wrong as you write to me. I was on the point to ignore you for that. But now is ok. I can see you tried something but it come out something totally different. Mistakes happen and I can understand that. It is no problem now.
Have a good night and I will take a more close look over the things you told me.
Also, as I already mentioned already, we also have the same mains as you in England. Also the same coloring codes for the wires. We , as you there, use 240VAC, at 50Hz, and brown and blue for live wires and yellow+green for the ground wire. And is the same for all europe, but i didnt check per say. I think is the same in germany, france, italy, etc. Even in Russia is not that different. I know in china they use 220Vac, so 20V under our new rectifications, but we had 220 also until 2010 i guess. I dont remember when the rectifications took place. Its an entire story about this subject alone, but you have a better idea now.
The only major difference between countries are the power plugs !
This page is very good, at the begining of the page you can find very good sumarized information of our system : Romania Power Cords | Romania Power Cords and AC Cables - http://internationalconfig.com/power-cords-for-romania-ac-power-cords.asp

 

[DPG]

That escalated rapidly!

 

[_q12x_]

We will reverse the order of the two circuits I mentioned ie low pass filter and then peak detector.....so that we only find the peak of the 50/60Hz signal. You understand why I have reversed the two circuits?

Not very well... because I didnt work before with such things. But I can imagine what you are referring to. You want to filter the 50Hz , instead of shielding it. That is a briliant idea and I hope it will work, I really do.
- Again, I bring the discution about IR, I leave IR to the remote control. But I just receive,phenomenally fast this time, my DTMF module, another interesting suggestion from another forum. MT8870 DTMF
I intend to use it for remote control. I have several options for remote control. I never worked with IR so I am expecting 50 IR leds and their receivers. I also already got this 433 Mhz RF Transmitter & Receiver.
also for remote control.
This is a paralel subject to the main discution, and I leave it for the last part, but im telling you about it now, because it is influencing our new option for the sensing circuit.

 

[_q12x_]

Mister @marconi, how is the whether in London now?

 

[marconi]

From left to right:

5V/2A dc regulated PSU...0-5V in 0.55V intervals LED analogue to digital voltmeter (ADVM) - test vernier potentiometer providing 0-5V voltage to DVM.

Tomorrow morning - 3 threshold peak voltage detector - for want of a better descriptor - to filter out spurious maximum voltage signal from ADVM caused by noise and interference.

 

[_q12x_]

From left to right:

5V/2A dc regulated PSU...0-5V in 0.55V intervals LED analogue to digital voltmeter (ADVM) - test vernier potentiometer providing 0-5V voltage to DVM.

Tomorrow morning - 3 threshold peak voltage detector - for want of a better descriptor - to filter out spurious maximum voltage signal from ADVM caused by noise and interference.

It's good that you are back, mister @marconi ! Now I am a bit happy.
It's a bit cryptic for me what you write there. I understand that you use a power source (PSU) for the circuit at 5V and probably set the maximum current at 2A. Mine I set it to 1A and it was more than enough and more safe. But the rest ?!? Again, i am not that familiar with the peak detectors or low pass filters that you are going to test. I have an idea about their existence but never worked with them.
I really hope your idea will succeed and that you will be able to teach me how to make it work in my side after that.
I thought on your idea and I can not make any logical connections between peak detectors and low pass filter and how to stop the 50Hz interference and allow only my hand interference to be "seen". I really hope you can make it. Probably you have far more better instrumentation than I have, and that will guide you probably straight in the hearth of the problem and resolve it. But is my guess. Im very curious what you can do ! Good luck !
I've also watched your movie, and then mister David movie from EEVBlog about peak detectors, link here:

and he is explaining them very well. But even such briliant explanation I still cant find in my mind the links to actually filter only the 50hz and leave my hand interference open to sensor. I dont have that kind of experience and knowledge and thats why i can't link anything in my head.
But is a fascinating idea that you have here, and for sure, like I said, with very good instrumentation you can find some sort of weak spot that can be used.

 

[marconi]

We decided to have a take away so while we waited I ‘stabbed’ the breadboard a little more to make the three level detector (TLD) for testing tomorrow morning. The three red LEDs at a slant indicate when each of three three levels have been crossed. The final output will be fed to an edge detector which will then toggle a relay on and off to control a lamp. Or something along these lines.

 

[_q12x_]

All I understand is that tomorrow morning you will do some testing. But nobody knows on what. We'll see what you get, after. Good luck there.

 

[marconi]

Output signal from three level detector passes to leading edge detector whose output is the input to a JK flip flop Toggle switch which operates single red Led to the top left.

Next step is to connect Toggle switch to relay to control mains lamp......