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marconi

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I have now watched 5 and 6. Only when I have watched all your video clips will I reply.

I have some 2N7002 making there way to me in the post for me to replicate your sensing circuit 🙂.

What a wonderful experimenter you are!
 
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I have now watched 5 and 6. Only when I have watched all your video clips will I reply.

I have some 2N7002 making there way to me in the post for me to replicate your sensing circuit 🙂.

What a wonderful experimenter you are!
I am very pleased you like it, really, but im a bit... sick of it. So many failures, one after another, literally. Please read my last reply, I put some modifications in it. My biggest problem is that I used the cardboard, and that is gathering some elecrostatic charge on it, i am aware, but i trade it for the maneuvrability and manufacturing ease I can achieve with it. Also very fast experimentation as you already are fascinated by it. Heh. It works for a large majority of circuits, but with this kind of sensing circuits, i suppose I push the limits with it. Eh well, I tried, right? :)
 
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I am not allowed to edit my previous posts? What an imbecility.
I just tested on the breadboard the same circuit for LM3914. And I got the exact same results as with my mounted IC, except the led1 and 10 are staying off when pin5 is in air. That is the only fault I have on my board, and I bet it is some sort of interference for those leds/pins.
Pin5 on 0V, nothing happens, all leds are off.
Pin5 on 5V, again, nothing happens, all leds are off.
But, when pin5 is in air, and touch it with my hand, some leds are on, but barely, very dim.
 

marconi

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I cannot spend much more time tonight because I am starting to cook. I would appreciate it very much if you did what I asked in my post from first thing this morning in order to establish which sub-systems do indeed function as desired. I suggested we first checked that everything from pin 5 to of LM3914 to the relay which switched the room lamp was operating as you wanted it to. If it does then we concentrate on the sensing circuit.

But it may well be that the sub-systems I have asked you to check are also subject to interference or disturbances which disrupts their reliable function.

To give you some idea of one of my lines of investigation you have 50 leds each of which consumes between 10 and 20mA say or in total between 0.5 and 1 Amp. The PURE power supply you showed in one of your YouTube clips outputs 5.5V and its rated output current is 1A. What current is required to operate the two relays which is extra to that for the leds? How well regulated or stable is the pure ‘s voltage output as the current supplied approaches its rated value - at the moment neither you or I know. Why does the voltage output of the pure matter? Because it may be affecting the operation of the sensing circuit.............
 
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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.
1611606636302.png
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.
 
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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

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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
 

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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.

IMG_20210126_095833 copy 1.jpg

I must also share this old sketch of mine:
1611648824713.png
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

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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.
 

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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

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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

 

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