I just made a search now on youtube afte you guys and i find you there as well. I just subscribed and I will tell you my opinion in time after watching a couple.

I didn't realize my content on YouTube could be found. I only have a half dozen videos posted and I made all of them private. They're just videos demonstrating something. I won't speak on them because I don't particularly like to hear my own voice or how it sounds to others.

So what now? What i can do? You think for me because you have more experience than me with these devices and phenomenas, and as you said, think on the worst case scenarios, and give me a solution to upgrade its sensing power.

I don't use MOSFETs much as amplifiers. I tried breadboarding your circuit using an AO3400 I had handy, but the typical transconductance of that device is 2 orders of magnitude greater than the 2N7000/2 (33 vs 0.32 siemens). I need to try with some 2N7000 so I get something more comparable to what you're using.

 

Sorry, i dont mean You- dl324, but you the website allaboutcircuits >
https://www.youtube.com/channel/UCYTq2bhe5pim45pAEU-gDjw
and now that you mention it, i did give a search after your name and this is what i get: (only 3 movies)

And apropos about voices, do you think i like my voice? Do you? Huh? Ofcourse not, i sound like an idiot. But i dont give a sh*t. Not when i have to make what i plan to make. When the future of humanity lies in my circuit board there. (I'm joking)

 

To boost the sensibility:
- Im thinking to add more sensing circuits in parallel. One is in middle now. So another one in the left of it and then another 1 in the right. So 3 will be in total. Its a thought.
- Another idea is to make a darlington from 2 x 2N7002, or 1x2n7002 and some pnp.
What i tried already, I took the same diameter wire (0.25mm) but longer as 40 cm probably. I didnt measure it yet. The effect is that the sensing is stronger when its closed loop, like a circle or oval. But is still too narrow the sensing activation- the leds are opening too fast from one to another, is what i mean. If its just an open wire it is weaker, like 3 or 4 times; if i remember right. I did the test some weeks ago.

 

Any results/ideas ?

 

Any results/ideas ?

Nothing yet.

 

You

A schematic will be easier to follow than this:
View attachment 225133

I agree, so I made the entire skematic as it is until this point.
It is made on a A4 paper (210x290mm) and scanned.
I can ink it in Photoshop, to clearly get rid of any ambiguity lines that are plenty because i erase a lot and they show from beneath.
My plan is to ink it in the very end, when all is working optimal and mounted. You tell me if its helpful in this form and if not, ill ink it for you. Also tell me if something is dubious or can't read clear enough.
I hope it will help you seeing it as a schematic and not as component placement as i originally show you.
All the resistors values are checked on board, as it is working right now for all modules/circuits. I also specify the leds color since they are working at diferent voltages by color. It should not make big difference in my opinion. I didnt specify the wings led colors though. Only the ones from surrounding circuits, because they influence (in my mind) the proper circuit functionality.

- Here is my account link image uploaded, if you can't see it here at its full rezolution, there is at its maximum for real:
https://www.deviantart.com/q12a/art/IMG-20201219-221439-SCAN-Image-864540519

 

Oh... and if you see any mistake in any of the circuits modules, please correct them, point to them, draw over them, whatever you can just to make this thing work properly and not at half as it is right now. Make it the proper way, and not as weird as I did it. I know for sure i did some extreme mistakes there, I can see them now, but not at the time I was working on it, since i was preocupied to be happy that "it works".

 

I was able to switch a relay with this circuit:
View attachment 225013

It stuck with me your simple and efficient way of thinking. And I realized that i made a grave mistake in the [sensing circuit]. It's not that i was mindless when i build it, but I was happy it worked as it was. So I stopped any further experimentation. Your way is the correct way, and it hit me, that i am not doing it right all the time. I should learn from you that i should rely on the absolute working functionality when it comes to small components arrangements. Like there are already standard configurations that are working without any doubt. In my defense, I dont know all configurations there are, so thats why im a bit wild with experimentation, because nobody will tell me anything, so i have to be wild. Ok, back to my problem:
Here is how i am thinking to correct it next:


I'll probably have to add a resistor in the Collector of the red transistor, to provide a smaller current to pin 5. But not too low. I'll have to check what is max voltage drop on pin5 of LM3914 and also its current. I dont remember if 5V is fine or not.
I remember that if I take the signal from the transistor with the led, the signal is way too weak. Probably 10-20mA that is after the LED, is too low.
Anyway, that's the plan so far.

 

I just checked in the datasheet and its between 0 and 12V.
"High input impedance" means very low current, so that is good.
Im not sure how signal can be 0V, only in OFF mode or logical 0, I presume.

 

Aah, Failure. It does not work with the red transistor.
It only likes the signal from the Drain of the 2n7002, directly. I also took the signal from before and after the led of the npn transistor, but only the #1 and #10 leds were open All the time, in sign or error.

 

Your schematic shows an NPN bipolar transistor but it is labelled a 2N7002 Mosfet. Its collector (maybe you call its drain) is connected to +5V. Its emitter (maybe you call its source) has a positive-going signal that the pin 5 input of the lM3914 needs.

Then recently you show connecting the collector of the BC547 LED driver transistor to the pin 5 input of the LM3914 but this signal is negative-going which is wrong.

 

Deleted double post. I should never use the "go back one page" on this website.

 

The maximum allowed input voltage and its tiny input current are shown in the datasheet of the LM3914.

 

Your schematic shows an NPN bipolar transistor but it is labelled a 2N7002 Mosfet.

Yes, you are right, now is modified.

 

And, the project is finished.
But I want 2 more addons to it. A laser and a remote control.
Watch the movie. I am not 100% satisfied but in general I am happy with it. It is fine as it is.

 

@dl324 you remember when we spoke about the oscilloscope and you suggested me a small one, and I actually go and buy it?
The order date was on Oct. 01 2020. Now it is cancelled because it did not arrived at destination. It arrived in my country after 1 to 3 weeks, but it just stay and not got moved just because they can. Im so upset. I also had to fight for my money with Aliexpress website refund, for 2 weeks because if I get at 3 months, they will close the refunding option, and I have a lot of money to loose and i did it on the latest expiration time period possible. Today, I received my money, after 2 weeks of almost daily writing to the seller there, who was very conveniently slowly and lazy responding. Aliexpress is a very bad market , at least for me, especially when they have to refund you. They forget that part and make it elusive even in their official form. I'm complaining i know, but is good to others to know my experience. I know you dont believe me on my words so i have a screenshot of the experience, here: (its a bit low rezolution but is readable)

After I clicked the [NO] checkbox, the [Next] or [proceed] button just simply dissapeared and I could not continue to finalization. WOW ! Right?
Trust me, on ebay they are waaaaaaaay more responsive when it comes to refunds. It is troublesome there as well, but they will not f**k you in the face like these proverbial c**ts. Im so upset on all the transaction all together. I really wanted to have that tool. Aaaah, oh well. We move on I suppose. Im happy that I got my money back, i was swearing I will never see them again.

 

We move on I suppose. Im happy that I got my money back, i was swearing I will never see them again.

That's the thing with Ali Express. Some Sellers are flakes and whatever Ali Express uses for feedback is bogus. I had a Seller claim they couldn't sell me a 5MHz DSO (battery operated) due to the coronavirus and asked me to cancel my order. I made them do it. I got one from another Seller, but it cost me around $10 more because I missed out on a sale and items had gone up in the months that I wasted waiting.

I see that scope listed on eBay and on Amazon. It might cost a little more, but you might have a better chance of actually getting what you order.

I keep after flaky sellers. It's more a matter of principle and trying to help someone else avoid disreputable sellers.

I have a thread about bad Ali Express sellers here.

 

Thank you for your feedback !!! I will look on ebay then.
I wish I could get a better tool that that. A second hand , is good enough for me.
A very old and very cheap is all im after, with milions of options if possible!!! Those are the best, in my opinion.

 

A second hand , is good enough for me.

Too bad postage to Romania is so high. I don't have much use for my DSO138 since I have the 5MHz battery operated follow on. A member on AAC who wanted to get rid of his parts gave me a kit for a DSO 150. I assembled and tested, but the battery operated one is much more convenient.

DSO 150 kit:

 

The postage in Romania and I presume is the same everywhere else... is that they literally hate the free postage. Because they put accent on pay postage, the higher the better. So everything coming through free mail, is intentionally neglected, sometimes you have the surprise of robbing its contents or parts of it, just to make your life and experience as miserable as possible, because... they point to the pay postage, "see? there is safe". So this is going on in reality. BUT... there are ways of bypassing them. I am not that well informed, and I should at some point in my life learn the entire list, I am still postpone it, but there are little things that are making the package faster and safer even with free postage. Little denominations, like express or recomanded , I didnt check their full terminology but if I ask at the postal office, the lady (hopefully older and more experienced) will tell me what is what. Usually I proceed like that when I had to send or receive something important. For example, a very good one, I took in 2014 a 4Tb hard disk from mister ebay. My hearth was in my neck the entire waiting period, but it come fast and safe, because the dude who send it was from germany, from a little company there, that they sell on ebay as well, and they "recomanded" or some specific postage word, that means its to be treated more serious than the rest. I did not retain the exact word name, but the postage lady told me with a curious nuance in her voice what it was. Because that is rare, from ebay to come like that, probably. Or from any other parts. I also remember I talk with the sender and warning him about throwing packages in normal mail and to assure it was well packaged and well shielded with foam, and he did indeed put me a very high and large quality foam inside. I still use that hdd today and is an awesome thing still. And at an extremely cheap price back then, I was really win this hdd than buying it. :] Haha.
- The real question, is how much you want for this oscilloscope? (I can make you an illustration, as an artist, you know? ) Hahaha.