How to shield a live wire at 240V ?

[_q12x_]

I have a electronic board with leds (made by me) that is driving a relay. When that relay is closing it’s contacts, is actually switching the 240V for the light bulb switch in my room. This board is quite long, like 50cm (half a meter). The relay is in the left corner, and the live wires from it goes in behind the board to the hole in the wall for the mains switch. I also have a mild steel sheet behind my board that is grounded. It is shielding the interference of the 50Hz from the live wires from the wall to my sensitive circuit. But even If I have this grounded metal shield behind my board, the live wires from the relay are still affecting my entire circuit board, keeping it ON all the time. If I am disconecting the live wires from the relay, the board is functioning very well. Another IF, is if I disconnect the ground from the metal shield, the circuit board goes nuts. So the shield is doing it's job fine, but only for the live wires inside the wall !!! But not for the wires from the relay to the live switch.
- I want a way to shield these wires !
Thank you !

 

[_q12x_]

But is not finished yet, even though I announce it in the title.
Ill have to go back to the original design of that SCM and add a pot and another 2 caps for filtering that protection for electrostatic. A lot of work and probably a brand new module. But I'm getting there. Ha
I suggest , mister @marconi to continue your experiment with the IR leds and the opamp. Im learning about opamps myself, so it is very beneficial for me to see your design with it... my greatest wish is that you make it intelligible enough for me to understand it right, as you progress.
Also, thank you for the "winner star" though it looks like you're the winner, lool & haha.

A bit out of context resolved issue I had.
Check this out: q20210213-Secure-Wire-Holder
Dont forget to zoom in, by clicking on the image to see it in great rezolution.

 

[marconi]

q12x = you are an inventor that is clear. And someone who repairs an item rather than replaces it. Most laudable. (As an aside BOSCH tend to repair their products because it is 'greener' and more sustainable - or so the man said when he replaced the complete washing drum assembly on our 2 years old washing machine recently.)

I have had a frustrating morning testing my IR array. I found:

1. Two transistors soldered in the wrong way round;

2. Two dry solder joints on the thick 5V bar;

3. A defective pre-made up jump lead.

All 'seems' to work correctly now but I will confirm that this afternoon.

I have bought myself a ruler to measure distance between hand and array. I don't want to report a fisherman's tale! See:

fish tale - https://idioms.thefreedictionary.com/fish+tale

 

[_q12x_]

q12x = you are an inventor that is clear. And someone who repairs an item rather than replaces it.

Aaaah, thank you very much that you like my experiments !
I got in the habit to test and also look up datasheet every time Im handling a transistor that is not new.
I have an ESR meter, very handy to get the pins of some weird --- transistors in my pile of everything.
But for my experiments I tend to use brand new for less surprises, though I risk it sometimes as well.
I am encourage you to keep up. It is frustrating indeed and imagine my frustration over 7months of consecutive failings !!! But when you want it bad enough...you must push the ---- out until is finished. Scuse my french comparation. Haha. But if you can make it with IR,for a longer distance, it will be way much better than mine because it will be much more linear effect. My effect is ...quite ----,I personally dont like it that much. But is working and is all I care for the moment. I'll get used to it I suppose. Thats why Im encourage you to finish yours. I unfortunately can not make any money, but you can, so I suggest you should buy a 1W or even 3W IR led, their price are very close and the power difference is quite big between them.
A single one should do it. I am encourage you, for the sake of this experiment, to buy one. Is 1$ as I showed you before. And you can use whatever IR detector you might have, since at that power, the ilumination will be super intense. It might reflect not only from your hand but from your entire body as well. Is what I predict. But that will be easily lowered and calibrated to whatever intensity/sensing is desired.

 

[_q12x_]

Good morning mister @marconi.
How is the heat in your home now? I hope is good. I am wearing thicker clothes and a jacket without arms, to keep me warm all the time, and thick socks on my legs. I dont get the cold by wearing the socks all the time.
I will not insist on you buying a new 1W or 3W IR led. I will buy one miself because its an intriguing experiment to make and >>I<< want to test this sensitive theory with it. I think it will make the circuit quite sensitive and for an acceptable long distance, using a power light source like that. Its cheap enough after some thought. You know artists, they like to complain, it's their favorite job.

 

[marconi]

I thought you might be interested to see a plot of the voltages Vsx where x: {1,2,3,4} when my hand was placed at a distance d from the array.

The first attachment shows you how I have labelled each photodiode; +, -, L, R.

The second shows the Vsx readings at distance of 30, 25, 20, 10 and 5 cm from the array. Nice to see that each Vsx is very similar for each distance.

These are the readings with no hand in front of the array: 0.69, 0.77, 0.70, 0.71V (mean 0.72V)

These are the readings with a hand at 30cm in front of the array: 0.82, 0.92, 0.89, 0.92V (mean 0.89V)

With a hand at 30 cm the mean voltage increases by 0.89-0.72 = 0.17V or 4 x 0.17 = 0.68V if the outputs were summed together.

In the third attachment one can clearly see the relationship between Vsx and distance as the hand approaches the array.

I will need more dynamic voltage range than is currently available from a 5V power supply since 4 x 4V = 16V. I have ordered some components to make a dual polarity supply 12V, 0V, -12V. I will need this as well to power the op amps.

 

[marconi]

Good morning mister @marconi.
How is the heat in your home now? I hope is good. I am wearing thicker clothes and a jacket without arms, to keep me warm all the time, and thick socks on my legs. I dont get the cold by wearing the socks all the time.
I will not insist on you buying a new 1W or 3W IR led. I will buy one miself because its an intriguing experiment to make and >>I<< want to test this sensitive theory with it. I think it will make the circuit quite sensitive and for an acceptable long distance, using a power light source like that. Its cheap enough after some thought. You know artists, they like to complain, it's their favorite job.

Good morning to you too. The boiler was fixed on Saturday and the snow has gone. Now we have the rain instead.

I was testing the array yesterday and exploring the variation in output voltage Vsx with distance. I have posted my results in the previous post.

I can increase the power output from my four IR LEDs. At the moment they only have a forward current through them of 21mA. The specification says this current can be 100mA continuous at 25C, a five-fold increase.

Power output of one IR LED assuming 100% efficiency electricity to IR = 0.1 x 1.6 (forward Volt drop) = 0.16W

4 x IR LEDs = 4 x 0.16 = 0.64W (ok - not 1W but quite a bit more than at the moment).

 

[_q12x_]

check out my experiments with the double power supply:

q20200928 Double Power Supply (+Vs 0V -Vs) by q12a on DeviantArt

www.deviantart.com

If you pay attention to the transformers, you will notice for sure, they are from england ! I have a friend who I asked to send me all his transformers that he wanted to throw away. Some were bad, but others were good. He misused them probably and thought they are bad or weak. The funny thing, even if I explain to him how to properly use a transformer, he still will throw it away. The transformer that is powering my wings projekt, is also an UK one, stripped of its legs and reshaped to suit my needs.
If you have friends like that, use their transformers! A good advice from romania right here. Haha.
My sensor curve is more steep, but in a big percentage, is pretty much like yours. I've already discussed the liniarity of the sensors. There are some dedicated IC that do just that ... but is an old conversation and I am only remembering it now. In principle, we must work with what we have, how shitty it is, must be glad it works.

 

[marconi]

I am impressed by your knowledge of electronics, so much so, I cannot understand why you are not employed in this field. In the UK there is a shortage of engineers and technicians although this is changing now as more and more young men and women decide on a career in science, technology and engineering.

What stops you working as an electronics technician in Romania? If you prefer not to say I will respect this.

 

[_q12x_]

Ah, thank you for believing me and remembering !
Well, im an artist and that is written on my forehead as "looser". And my society respects these rules very much. So I have no chance in hell. I asked people that work in electricity/electronics domain but they ignored me, because is my best guess, its too much incompetence and job fight already on some fixed positions, like it is everywhere else. THe same was (and is) in school, if you want a teacher position. Now is full of old women and I as a man... just pushed away very conveniently and easy. Its my experience. So... thanks god to this epidemic and good doctors who find the problem lighting fast these days, because making money is impossible. Im staying home for 8 years doing my digital art and only 1 american priest pay me from his pocket for some work i did and that sums up to the glorious 200$ in total 8 years. A single teacher salary in 8 years. Eh... what we can do? Partly is my decision to stay home, so I wanted the quiet and free time. But is time ...well, im saying it for 2 years now, to get serious and look for work more insistent. I will see. But the bottom line is that from online, I could not get anything from what I do best, my art. Im also a good programmer but unfortunatly in C# and not C++ and that is an eternal regret. But im quite good. And again, no chance in hell as a programmer as well. That is a job for the young people, not old farts like me. Haha. Again, eh well, what I can do? Wait to hear and weap on my try to phisically reach the games companies here in romania, what a bad joke it is there. I thought is a good idea to try my art skills to them, but wait, 1000 young people on the gates... and I could clearly see there is no chance in hell. Overpopulation... what can you do? Haha. At least I have left a good humor sense to lough on others trying to make money. Too much history, but you poke a fragile spot for me. I made it as short as I could but is more complex and detailed and tragic than I barely expose it here. Eh... shait (capitalistic) life.

 

[_q12x_]

Don't be so easily impressed my dear friend @marconi, because I only know a limited side of things and I can build less than what I know. I learned myself electronics, in 30 years, sporadically, when I had the time and being unstressed (like I am right now at home). Ive also learn it in paralel with other disciplines and also perfecting my digital art skill in the same time, which was a mountain of effort and pain to do it. Even home, I have to fight with psichological monsters like constant depression - that is a linked side of being an artist, and an immense ferocious negative internet art feedback, especially from other artists, who are unwilling or unknowing how reality stands, how hard everything is. Well... I had to peace that out as much as I could. Now if im poking my head out.... ill have to re-adapt to the jungle.
You are maybe more impressed by my art skills, because that is really showing off. Haha. More than the thing itself. In reality, im not that good, even my art is presenting it like a wonderful thing.
But im very glad that my art is presenting itself like that, because it was(still is) exactly my intention.

 

[marconi]

Thank you for your two replies. Your artwork is impressive too and prolific. You are in a hyper competitive market which you do not need me to tell you.

We can enjoy working on this project, a creative work of art in itself. Any honest appreciation of what you have done so far shows how close you are to your desired solution.

Would you like me to send you some new electronic components which might be difficult to obtain?

You might want to research why my initial thought of using a non-inverting summing op amp circuit is a poor one; an inverting summing circuit is the right choice. (In my defence I am trying to remember electronics lectures from 40 years ago).

 

[_q12x_]

Thank you for liking my art ! I'm glad you took a look on it. But im really here for the electronics help, more than my art appreciation, so to be clear what are my intentions. I was a bit too open perhaps, in my description, but is the truth.

Would you like me to send you some new electronic components which might be difficult to obtain?

I have what I need, thank you very much for your thought. From curiosity, what you have in mind? Im not phishing for free stuff from anyone I dont know, only from my friends that I really know in reality.

We can enjoy working on this project, a creative work of art in itself. Any honest appreciation of what you have done so far shows how close you are to your desired solution.

I wished I would be closer to what I was originally envision.

Q20201010 - Light Switch Design by q12a on DeviantArt

www.deviantart.com

Do you see those fragmented parts on the wings? Those are intentional there. I originally wanted to add a motorized mechanical assemble. When I get close with my hand to it, to OPEN !!! How cool is it? Right?
You see it?
Also, that white shape should be as PAINT thick, yes, 0.01mm thick. But... the leds and IC thickness, I had to compromise and it looks as it is today.
My next plan for it is to add a buzzer that will "tick" every time each lm3914 Led Pin is activated. I have no idea yet how to implement it over already so much jungle of wires is there already. That will be tricky, and I will have to make probably a separate signal amplifier for that buzzer alone. Pain in my as is what it is. Haha. But it will be glorious. That's what it counts.
Another more easy add on is a remote control. Thats why I asked you to continue with your IR development. Because this was planned from the start, even if you cant possibly believe me, but I tell you, it is true. Im speaking about it in my movies I made.
So ...thats it... of what I want more from it. Not that much really. Right?

You might want to research why my initial thought of using a non-inverting summing op amp circuit is a poor one; an inverting summing circuit is the right choice. (In my defence I am trying to remember electronics lectures from 40 years ago).

I am so rookie with opams ! I barely made a couple of circuits with it and all were tutorials or tests. I still have no practical idea where and how to use them. That is left to cover in detail for another time. Now I have to concentrate on this to finish, at least the remote to add and I can call it done after that.
I am partially, planning to integrate an opamp in this led wings circuit, but I can see it will complicate the hell out of it, and is already complicated as it is. I will see. If the opamp will work from only the positive to gnd rails, excepting the negative positive rail (-5V), then I will very much consider it. But I dont want to concentrate too much on it for the moment. I want to resolve the other problems first.
Thank you for your nice reply! It's a pleasure to talk to you.

 

[marconi]

You do not seem happy with what you have achieved so far which I think is a shame. If you were to start your wings project again, knowing what you know now, what form would it take? The problem with prototypes is that generally they are not meant to become the final product. Or do you just want to complete the construction you first started?

In my experience the lessons learned from making prototypes makes constructing the final product easier but not necessarily easy. The final design is not then what you began with. I want to repeat that what you are attempting to achieve is very difficult. Product design then is the art of the possible and practical with the technology being employed. Compromises are usually necessary. Therein are the clever design decisions on what is good enough. Look up the Pareto principle.

compromises meaning - Google Search - https://www.google.co.uk/search?q=compromises+meaning&ie=UTF-8&oe=UTF-8&hl=en-gb&client=safari

It may not be that that you would start again but would instead reduce your ambition as to what you could reasonably achieve with the technology being employed.

 

[marconi]

Back to work. The components have arrived to make the dual polarity power supplies. Plan for today is to make the 12, 0, -12V supply and then the inverting summer and unity inverter. The diode is to ensure that Vs is only ever a positive voltage to the comparators.

In my first circuit I had a ladder of resistors providing the voltage references to the 8 comparators. For the next version I will have a potentiometer across 0-5V for each comparator referencce input. This way I can make the progress of illumination of the LEDs linear with distance.

 

[_q12x_]

Enumerate me your components that have arrived.