How to shield a live wire at 240V ?

[_q12x_]

The use of 8 trimmer pots to provide the 8 reference voltages should allow me to cause the LEDs to illuminate in equal distance steps As the hand approaches the sensor. Not yet calibrated - work for tomorrow.

Very interesting indeed - I want to see how had you think it. Make me a circuit diagram please.
I know is boring to draw, but you must do it for me because i find it very interesting.

 

[marconi]

Of course I will draw for you. It will not be tonight though.

 

[_q12x_]

Of course I will draw for you. It will not be tonight though.

When you have time of course and thank you ! I have a couple of uA741 opamps, and I am thinking to reproduce your circuit that you just built. I know, I should buy more newer opamps but these I already got in considerable number so why not use them. I will learn about opamps a bit more in this way. I think you just made a very cool project right now. And Ive also mentioned using opamps at some point, for the scm and yours here is just my wish come thru.

 

[_q12x_]

How is the drawing and the pot calibration going, mister @marconi ?
If I will manage to built it after your draw, I might assist you. Haha, jocking of course, since im not that good with opamps.

 

[marconi]

I have had a frustrating day. I bought some pre-wired jumper leads in different colours and lengths. I have discovered that some of them have no continuity between ends and others only intermittent continuity. Even the ones which do have reliable continuity do not make a reliable connection in the contact holes of the breadboards I use. I will go back to using solid bell wire which I have never had any problems with ( illustrated below the yellow jumper lead).

So not much progress today because I have had to track down defective leads and connections. I will draw op amp circuits tomorrow.

 

[marconi]

Are you about to start work on an infra red sensor circuit module like me?

741 are good and reliable. You can use them as comparators. You can use them as voltage summers, amplifiers and inverters and for many other useful circuits.

Operating an op amp using a 0 to 5V single sided supply is very limiting. How do you plan to produce a double sided supply of at least 12, 0, -12V? My second prototype is using 12, 0, -15V supplies and 0, 5V for the logic circuitry. The 741 can operate on +/- 22V but the recommended upper limits are +/-18V.

The higher supply voltage enables more Volts per mm from the sensor which in turn increases the voltage steps between each Vref for each comparator and led.

Once I have a way of adjusting the Vref for each red led on my ruler I plan to experiment with a few led/photodiode arrays to see how closely they meet your requirement. You have seen a picture of the first one already.

 

[_q12x_]

Thank you for your response my friend mister @marconi.
I had numerous problems with my breadboard contacts and wires as well. I do not have the money for fancy wires like yours. I made some multiwires wire like you have, using simple scrap wires, pins from dead components, especially leds, which have that nice square leg profile, solder and heatshrink rubber. I build 2 black and 2 red like that for more than 5 years and I had using them extensively. Never broke ! I also have a kit of pre-bended solid wires for breadboards, in which I trust very much, but is a bit harder to use them on too much agglomerated circuits. Because these limitations, I learned to build on modules. You heard of them? Haha. Me and my humor, ei?

I got surprised I can not find the exact model colors I have. These are very diferent color coded. I think mine are prettier. Or I am just simply too used to them. But this type of wires I use. Very secure very robust. The breadboard is giving signs of unsure connections in some specific spots that i didnt find yet. I put some larger diameter wire for sure and that widened the little clamp inside some holes. But is a little percentage damaged and I can live with it though I have an eye on it all the time when something goes south and it shouldn't.
I didnt do much as well. I just happily use it. Im telling to myself this is a usage test so... it already passed probably 1 week of usage the entire board. And is working more than fine. Excellent. I'll have to play with the remote control for the next module. That part is easy since I have some already made modules from mister ebay. I will try them first and if something goes south, ill go into more experimental remotes. I hope not.
Now...I have a quest for you. It is purely a... design problem. Or connection problem. I want to hear a "tick" from a 5V buzzer. There are 2 types and I have both. The passive ad active buzzers. I was stupid to take the passive ones first and then discovered the active ones existed. But now Im thinking to add a tick sound for each 1-10 pin activation and using a passive buzzer that only make a "tick" when is getting voltage on it. Is how I am planning at this point but I must make tests. Maybe the active buzzers are the solution. We will see. SO your quest is to tell me how you will link another 10 wires on the already finished board as it is. Draw on top of it or just explain, just make me understand your solution. So, understand me well, im asking you not the circuit how should be, but the wiring. Because if the wiring goes to hell, and becomes too complicated, then I will not build anything about sound, indiferent of how much I would love to hear it. This is plan A. If plan A succeeds, plan B is to create, built and test the sound circuit.
Thank you for your understanding and help, mister @marconi .

 

[marconi]

Here are two circuit diagrams. The quad comparator ics I used can only sink an output to -15V. This is what the drawing top right of the second attachment is attempting to show.

The summer circuit sums the Vsx inputs but also inverts. So if the Vsx inputs where 1, 2, 2, 4V the output would be -9V. The unity gain inverter changes the -9V to +9V.

One has to be careful not to saturate the output of the op amps ie: the output must swing between +10V and -13V if they are supplied by +12, 0, -15V rails. Probably could go closer but I like margins in this case of 2V.

The VR1 pot on the summer is to adjust the peak output of the summer so it does not saturate nor send a signal to the inverter which would saturate it.

I made a mistake in ordering the voltage regulators because I meant to buy a +15V positive regulator but clicked on +12V. This explains why why comparators are operating using a negative going signal because the -15V side of the supply gives me a wider voltage range ie 0 to -13V whereas the other side only provides 0 to +10V.

The 741 has a complementary pair of output transistors and so can sink to the negative rail or source to the positive rail. Worth studying the data sheet for a 741 and to note the tips on circuit layout.

https://www.ti.com/lit/ds/symlink/ua741.pdf

The 741 can be used a a comparator and its output can drive directly a small led (via a series resistor to limit the diode current.). Thus with several 741s and a trimmer pot providing a Vref to each you can produce something similar to me. Also provide a test pot to generate a Vs to confirm you comparators light their LEDs dependent on the Vs and Vref.

I hope this helps.

 

[marconi]

I will reply to your #207 later when I have time to read it carefully. I have to go out now.

 

[_q12x_]

Thank you very much for your circuit drawing ! I know it was hard to make it. There are some little notations that I am not used to, but I think I figure them out already. I read all your text very carefully and also read both schematics. So far, i can't say anything, but I will say a lot after I built it. Unfortunately I only have 5V power supplies. (7V I just look from the transformer). Hmmm, from my earlier tests I know the 741 is capable of working in 0-5V quite fine. Ofcourse I am not that efficient with opamps. I hope 5V will not be a problem. If it is, then I will try to find another higher power supply. Until then, I will use what I have. Thats all I can say until now.
Referring to your 12V regulators mistake instead of 15V, I think it is possible to create a custom regulator from components at what value we desire and how strong we want it to be. Hopefully. But this is another project to make with opamps that is put in plan/future to make. I think is a very interesting project.

For your practical reasons, I think your project is complicated enough and my solution here will complicate it even more than it is , so ignore it if you think is too much, and take it as a possible/alternative solution when in need, like you are now. My google search input is "build a regulator using an op-amp" and I switch to images to get a plethora of similar circuits like the example I put here.

 

[marconi]

To check my understanding of your request- you wish for a short tick each time one of the 10 outputs of the LM3914 goes low to 0V? A tick not a buzz?

Do you obtain a tick sound now if you energise the buzzer? I guess this will be from the passive buzzer. Is there another tick when it is de-energised?

And if you energise the active buzzer it buzzes until de-energised?

 

[_q12x_]

To check my understanding of your request- you wish for a short tick each time one of the 10 outputs of the LM3914 goes low to 0V? A tick not a buzz?

Do you obtain a tick sound now if you energise the buzzer? I guess this will be from the passive buzzer. Is there another tick when it is de-energised?

And if you energise the active buzzer it buzzes until de-energised?

Yes, A single beep/tick. Not a long sound. Like a keypad from a telephone, the duration. Even shorter duration. Blip, and thats it. For each pin a blip. So it will be 10 consecutive blips when I activate fully from 1 to 10.
I didnt test anything yet. I might have to make an amplifier for that buzzer alone.
But please concentrate on how to make the connections first. I know is a bit contraintuitive but it is really what I need the most.

 

[stevethesparks]

I've always found these publications useful.

 

[DPG]

I've always found these publications useful.

I've got about 30 of the Babani range of books from many years ago. Good for basic reference and circuit ideas.

In fact I've got a well thumbed copy of How to Use Op Amps.

 

[_q12x_]

I've always found these publications useful.

I've got about 30 of the Babani range of books from many years ago. Good for basic reference and circuit ideas.

In fact I've got a well thumbed copy of How to Use Op Amps.

Thank you, I am a rookie in the experimentation/practical sector. I have already a ton of data/pdf's collected, also time I spent read all I could find about them and watched tons of video material from youtube. I have a good idea what they are and what can do. I have a very limited experience so far with them. I am still uncertain on using them, because i need greater and more profound experiments circuits, to be able to actually design with them. SO that is what im in search actually.
But everything you can give me (as pdf's) is well received. Again, the practice interesting and practical circuits is what im after and I lack experience. I best learn from practical use.

 

[marconi]

What I recommend is that you take your voltmeter set to dc and measure the voltage change on each of the output pins of the Lm3914 to find out what are the high and low states. And then draw a graph showing how each output changes with the proximity of your hand to the SCM.

Studying this graph you will discover that the outputs cannot be used directly to create a tick sound - another circuit is required between these outputs and the Tick Module TM. Or you might decide to include this circuit in the TM.

It will be the ten outputs which you will use to drive your tick module. The question is whether to use these outputs directly or to buffer them first in order that your tick module does not load and thereby disturb the brightness of the LEDs. I leave it to you to determine the best place to connect to the ten LM3914 outputs.

If you send me details of the two types of buzzer I will take a look at their specification.

 

[_q12x_]

I said already, that I plan to make a separate amplifier for the buzzer and the 10 inputs to it.
My biggest problem is how to wire it. That's it. Doesn't matter then, I will find a solution myself.
This sound thing is a distraction for both at this moment. I only put it in perspective.
At this moment I am playing with the transmitter and receiver boards. Im figure them out.

This is what I have.
I am not sure what is that DATA voltage. Im supplying them at 5V both on my breadboard. I put a led and 10k on the receiver DATA and when I touch with my finger the DATA from transmitter, the led turn on. Thats cool so far. Now I need a minimum and a maximum DATA voltages that I cant find anywhere. Hmmm. I assume is 5V. What you think?

Further: I put a 1M,then 100k ,then 10k between +5V and DATA and the led is only lit when the contact is made but it is immediately turned off. That suggest I need a variation on the DATA pin. Hmmm. That sucks a bit. To be able to mentain that led On all the time.

 

[stevethesparks]

I said already, that I plan to make a separate amplifier for the buzzer and the 10 inputs to it.
My biggest problem is how to wire it. That's it. Doesn't matter then, I will find a solution myself.
This sound thing is a distraction for both at this moment. I only put it in perspective.
At this moment I am playing with the transmitter and receiver boards. Im figure them out.

View attachment 64975
This is what I have.
I am not sure what is that DATA voltage. Im supplying them at 5V both on my breadboard. I put a led and 10k on the receiver DATA and when I touch with my finger the DATA from transmitter, the led turn on. Thats cool so far. Now I need a minimum and a maximum DATA voltages that I cant find anywhere. Hmmm. I assume is 5V. What you think?

Google AZ-delivery. You should find the information you require there.

 

[_q12x_]

I start to make the Remote Control test and with a little success.
I made a short movie(6min) in which I present what I did so far:

 

[DPG]

I said already, that I plan to make a separate amplifier for the buzzer and the 10 inputs to it.
My biggest problem is how to wire it. That's it. Doesn't matter then, I will find a solution myself.
This sound thing is a distraction for both at this moment. I only put it in perspective.
At this moment I am playing with the transmitter and receiver boards. Im figure them out.

View attachment 64975
This is what I have.
I am not sure what is that DATA voltage. Im supplying them at 5V both on my breadboard. I put a led and 10k on the receiver DATA and when I touch with my finger the DATA from transmitter, the led turn on. Thats cool so far. Now I need a minimum and a maximum DATA voltages that I cant find anywhere. Hmmm. I assume is 5V. What you think?

Further: I put a 1M,then 100k ,then 10k between +5V and DATA and the led is only lit when the contact is made but it is immediately turned off. That suggest I need a variation on the DATA pin. Hmmm. That sucks a bit. To be able to mentain that led On all the time.

I think those modules are for transmitting digital data over radio. So the data pin is not expecting a varying voltage or resistance, but actual 0s and 1s.

 

[_q12x_]

I think those modules are for transmitting digital data over radio. So the data pin is not expecting a varying voltage or resistance, but actual 0s and 1s.

I sincerely have no idea what those DATA pins supposed to do. If you can find me some good information about them, it will be nice. I think, in my opinion, if im adding a microphone to the DATA transmiter, on data receiver I will get the sound, analogue. And probably digital as well. I really have no clue. I only play around until I make it work.

 

[DPG]

I sincerely have no idea what those DATA pins supposed to do. If you can find me some good information about them, it will be nice. I think, in my opinion, if im adding a microphone to the DATA transmiter, on data receiver I will get the sound, analogue. And probably digital as well. I really have no clue. I only play around until I make it work.

Have you got a model number or any data for the modules? I don't think they are intended to work with audio signals.

 

[_q12x_]

Have you got a model number or any data for the modules? I don't think they are intended to work with audio signals.

This all the information I could grab from the ebay seller I buy from, and put it in this word document.

 

[marconi]

A little bit further forward.....

The same behaviour can be obtained with the hand.

By no means finished yet.

 

[DPG]

A little bit further forward.....

The same behaviour can be obtained with the hand.

By no means finished yet.

That is a great result. Looks nice and linear and stable.

 

[marconi]

I said already, that I plan to make a separate amplifier for the buzzer and the 10 inputs to it.
My biggest problem is how to wire it. That's it. Doesn't matter then, I will find a solution myself.
This sound thing is a distraction for both at this moment. I only put it in perspective.
At this moment I am playing with the transmitter and receiver boards. Im figure them out.

View attachment 64975
This is what I have.
I am not sure what is that DATA voltage. Im supplying them at 5V both on my breadboard. I put a led and 10k on the receiver DATA and when I touch with my finger the DATA from transmitter, the led turn on. Thats cool so far. Now I need a minimum and a maximum DATA voltages that I cant find anywhere. Hmmm. I assume is 5V. What you think?

Further: I put a 1M,then 100k ,then 10k between +5V and DATA and the led is only lit when the contact is made but it is immediately turned off. That suggest I need a variation on the DATA pin. Hmmm. That sucks a bit. To be able to mentain that led On all the time.

q12x Sorry I have not properly answered or responded to your query but I will try to over the next few days. Ok?

 

[_q12x_]

to mister @marconi

 

[_q12x_]

q12x Sorry I have not properly answered or responded to your query but I will try to over the next few days. Ok?

Dont worry, now i am challenged in making the remote plastic or metal box and is very hard. I hope I can make it.

 

[marconi]

I need to hire a new cameraman.....

 

[_q12x_]

I need to hire a new cameraman.....

Yes now I could see it and thank you for re-uploading it.
Interesting results. Again, I was ON to it before you making the video. Very cool that the calibration worked out (if you indeed re-calibrated). But I think you did.

 

[marconi]

(Yes I did calibrate the comparators)

Attached is a marked up circuit diagram of how to connect the Tick Module to the LM3914.

You will need a circuit which will create a short pulse (0V to 5V to 0V) each time an LED output changes state from 5V to 0V ie when the LED illuminates but not when the LED turns off. And then another circuit to combine these pulses in a logical OR gate. The output of this gate is a short pulse as before each time any one of the 6 LEDs turns on.

The output of the OR gate 'tells' the Tick Module to sound a tick.

This will produce a tick for each LED illumination as the hand approaches the sensor but not as the hand is withdrawn and the LEDs extinguish. You could if you wish have a tick as the LEDs extinguish but I understand this is not what you want to happen.

Is this the level of advice you wanted? I am being careful to leave you the interest and challenge of designing the circuitry - but am ready to help if you wish.

 

[marconi]

Using the 433MHz RF Transmitter and Receiver with Arduino - Electronics-Lab.com - https://www.electronics-lab.com/project/using-433mhz-rf-transmitter-receiver-arduino/


The 433 MHz Tx/Rx is an Amplitude Shift Keyed data link designed to exchange data as 0s and 1s by 'no transmission' and 'transmission' respectively. There are two identical data outputs on the receiver.

Data is represented as 0s and 1s. Or Off = 0 and On = 1. You have demonstrated this already.

The Tx and Tx are meant for two state data signals.

I have found a project in which your Tx and Rx modules have been connected to two Arduino computers. This indicates to me (I have no experience of Arduinos) that the input and output logic levels of the Arduino are compatible with the input and output logic levels/states of the Tx and Rx modules.

If you read this next link you will see a figure showing the voltage ranges for logic states 0 and 1 depending on whether they are for inputs or outputs. The reason that they are not the same for input and output is to ensure 0s are output and interpreted as 0s and similarly 1s are output and interpreted as 1s in the presence of interfering noise and pickup. There is a 'no-man's land' between the voltage regions for 0 and 1 in which it is undecidable whether a 0 or 1 is meant. The width of this no-man's land is different for input and output signals to maximise reliable data communication. The Arduino logic levels are included as a figure.

Logic Levels - learn.sparkfun.com - https://learn.sparkfun.com/tutorials/logic-levels

I would not directly touch the data input to the transmitter because it may be damaged by static electricity. Use a button/switch or have a (sacrificial) buffer transistor circuit whose input has the electrostatic protection afforded by the two reversed biased diodes.

It is also good practice before handling semiconductors and circuit boards to touch something which is earthed to discharge any body/clothing static electricity. Even if static does not immediately damage the semiconductors it can weaken their fragile junctions.

PS: Note the 4mA quiescent current of the Tx module.
PS2: I reckon I am now up-to-date on responding to your earlier posts.

 

[_q12x_]

Yes, you are up-to-date on responding to my earlier posts. Haha.
I am after a more elegant wiring for those 10 pins. Your idea I didnt think on it so its a new way, and I put it in the box of ideas for now. I am imagining to make some holes and wire through the back of it. THats an idea. Another one is to add it on top, next to the scm. This way, all the wires will go straight up and not diagonally like in your case. But your idea is good enough, because now im thinking that up or down on the same side of the 2-10 pins of the IC (it's right side). Thats why I engage people in idea comunications, because sh*t surface more easily. Haha. You like my analogies,right. More ideas ,let's consume all variants first, as stupid they may look at the first look, i dont care. All i care is to be practical and hopefully, easy to assemble. I am also thinking on a wire, like those old PC HDD data cables wires, all in a single cable IDE ATA they were called. I still have some in my boxes.
example here:

Oh, and thank you for the in depth documentation for the remote. I already built a case for the bateries, wait to see my "3d printer" resolve. I have the same problem as before. On the breadboard, is working in a way, but when I assemble everything, is working in completely other way. Lucky me, is not that far away.
I will provide img or movie until tonight. I have already like 7h of constructing that little sh*t and im just taking a break to steam off, by writing here to you guys. Man, is very hard work, I tell you. Especially the cases. Terrible work. But they must be done, because I can and want and know how.
You, think on more ideas to connect those 10 pins outside the IC area, please. I couldn't imagine everything from the start. I imagine from the start until I am right at this moment, with it on the wall, and in perfect working state (which im very impressed, it didnt sh*t itself even after 1 week of routine usage.
Oh, and very good observation about electrostatic defence on the data pins of the transmitter ! I will add those diodes to it as well. Good idea !

 

[marconi]

1/12 Streets Ahead Dolls House 50ft Double Flex Lighting wire DE086 | eBay - https://www.ebay.co.uk/itm/1-12-Streets-Ahead-Dolls-House-50ft-Double-Flex-Lighting-wire-DE086/362653072264?_trkparms=aid%3D1110009%26algo%3DSPLICE.COMPLISTINGS%26ao%3D1%26asc%3D230925%26meid%3Db034dc6f9bb844d482acfca49ae2978f%26pid%3D101196%26rk%3D5%26rkt%3D12%26mehot%3Dpf%26sd%3D193877709939%26itm%3D362653072264%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DItemStripV101HighAdFee&_trksid=p2047675.c101196.m2219

I have used this very thin white twin flex to wire the doll’s houses my wife constructs. Might this be discreet enough to make connections ? It is less than 2mm wide and less than 1mm deep. If you search hard enough you will find there is even thinner wire available from doll’s house electrics suppliers almost like cotton thread. You need to be a vascular surgeon to use it!

Ultra thin insulated connecting wire | Component-Shop - https://www.componentshop.co.uk/cable/ultra-thin-connecting-wire.html

 

[_q12x_]

I have used this very thin white twin flex to wire the doll’s houses my wife constructs. Might this be discreet enough to make connections ? It is less than 2mm wide and less than 1mm deep. If you search hard enough you will find there is even thinner wire available from doll’s house electrics suppliers almost like cotton thread. You need to be a vascular surgeon to use it!

WOW you really did a great job. I have no idea about your type of wire. But I do have some very thin enamailed copper 0.12mm, 0.17mm, and 0.25 that you know it already that i use it extensively. If you have a micrometer or a caliper, measure it for me and give me it's exact diameter. It is interesting what you thought. Again, an idea for the box with ideas. Again, I know is strange how you find me thinking but im gathering ideas like these in my virtual box of ideas for years, and I have many wonderful boxes - it's all in my head ofcourse.

Thinking about your find....its not too much about the thickness. Thickness is important of course but to a point. Im more interested in the [strategical and smart] signal steal from those pins.

 

[_q12x_]

[Remote Control Transmitter and Batteries Built in one day]
Here is 1 day of very hard work and very good results.
I apologize for a very long movie 21min.
But you will see in it how it behaves on the breadboard and how is in my hand. Also some photos of how was built, and also my "3d printing" method I used. I hope I keep you interested in it to actually watch it.

Thank you for your help so far.

 

[marconi]

I will look later. Looks interesting. I cook a meal and then take it to my in-laws every Tuesday evening so cannot pay enough attention right now.

 

[marconi]

Switch - Wikipedia - https://en.wikipedia.org/wiki/Switch

A brief response on something which is probably at play with your remote control battery switch - contact chatter and contact bounce. A mechanical electrical contact especially at low currents rarely establishes contact - and sometimes even when it breaks contact - without a spate of on, off, on, off, on, off... This can be fixed.

I assume you know why the closest led gradually brightens and dims and why the furthest one is either on or off?

Those coin batteries will not have the same ability to deliver power/current and maintain their terminal voltage as your lab power supply. Internal resistance and emf fade/recovery. I have an unreliability problem with a similar technology we use at home to remotely unlock the front door wirelessly using remote control ‘zappers’ More later.
Got to go.

 

[_q12x_]

I think I can add a 555 IC multivibrator circuit to the DATA pin for transmitter. That will create a smooth data for what he needs to react and transmit. Or a simple flip-flop I think will do the trick.
I am suggesting a couple of possible motifs for the smooth operation of the transmiter on the breadboard inside the movie. 1-that i am the antena and it picks up some signal from me. 2- the close circuit everything on the breadboard is powered. 3- the breadboard itself, its construction with all its metalic armature inside, might influence the result. I was partially didnt expect it in hand, to work as on breadboard as I experience it before with the SCM itself.
But I highly desire the same function to have "in hand" as on the breadboard for that led from the receiver!
If I can manage that, it will be great.
It is great so far, that is working, even with bumps, I am extenuated, more psichologically than phisically. And happy in the same time. Its a weird feeling.
Immediate next step I will make, is to integrate that receiver module on the board and see all the thing in action, and I really hope, without any interference of any kind or color.
We will see, soon enough.

 

[marconi]

Well done with producing not only the Tx design but also the interesting video. I admire your dexterity and imagination to use simple materials in both a fine and robust way eg: the matchstick and cardboard enclosure.

Three recommendations on what to test and confirm for the Tx:

1. pressing the button produces a reliable on action to connect 6V to the Tx chip.

2. Touching the data contact wire reliably produces a pulse of radio frequency.

3. When you stop touching the data contact wire the transmission ends Cleanly.

4. Measure the battery terminal voltage when not transmitting and when transmitting and then immediately at the end of a transmission. How does the battery behave? Does it need a little while to recover? The radio transmitters we use need a short time to recover after each transmission which gets longer as the batteries become more and more exhausted.

5. Must you leave the end of Tx uncovered by you hand and does the orientation of the Tx matter eg up and down or level with the floor. Our remotes work best level because the 5 cm wire Rx aerial happens to be horizontal. (polarisation of radio waves)

Do some thinking before constructing a pulse generator circuit on what remote control functionality you want beyond remotely controlled on and off.

got to take my wife to an appointment now.

Basics of Wave Polarization Explained - https://www.rfvenue.com/blog/2014/12/15/wave-polarization-explained

 

[marconi]

I have ordered some 940nm ir LEDs and photodiodes to make some longer wavelength arrays. So far they have been 850nm ones.

I found this scientific paper to learn more about how human skin reflects and absorbs ir rays. Do not worry about the mathematics just read the words if you are interested.

https://www.osapublishing.org/Direc...4-35-10559.pdf?da=1&id=333549&seq=0&mobile=no

 

[_q12x_]

I have ordered some 940nm ir LEDs and photodiodes to make some longer wavelength arrays. So far they have been 850nm ones.

I found this scientific paper to learn more about how human skin reflects and absorbs ir rays. Do not worry about the mathematics just read the words if you are interested.

https://www.osapublishing.org/Direc...4-35-10559.pdf?da=1&id=333549&seq=0&mobile=no

your link is giving me an error:

Always check the links you send ,if they first work in your side.

 

[marconi]

These are the items my links should have shown you.

My ir sensor has the predictable problem of variable ambient ir radiation pick up. Worse of course during the day. One of the reasons for trying 950nm ir is it less reflective off skin which may reduce pick up of ambient ir reflected off it and thereby emphasise the ir from the led illuminators. We will see.

I also thought I could pulse the illuminators which would create pulsed reflections I can build a circuit to distinguish from the ambient ones. As ever work in progress and most interesting.

I bought a sounder too to tick.

 

[_q12x_]

I was waiting for you to send me back that link that didn't work. When you send the link, make a test if its working in your side, immediately after you send the message. Then you can press the "edit" to change the link if is still not working.
Officially they are called buzzers and not sounders. Is a keyword that works in google and on ebay or any other online market. I am using the correct one because I learned to respect these keywords over the years and they just work. So get in habit to use them correctly as well. Its how I do things and it helped me.
I already find the solution for IR problem. You need much more bigger wattage IR leds to be able to reflect from your skin or any other opaque material. Just try it my way and we (both) will see if is true or not. I didnt test it but I think it might work. THese little 5mm are good if the receiver and emiter leds are pointing at each other, and not reflected like you are trying there.

 

[_q12x_]

I made a "quick" (10min) movie describing and showing the problem with Rx Data pin (its output).

 

[marconi]

I will take a look later but more likely tomorrow morning when I get up.

Could you clarify something for me please? Have you actually done a 1W IR led shining on your hand and then reflected back to a photodiode? I know you did a beam interrupter system using visible light LED and PD. If you did how did you arrange the IR led and photodiode at one place? Also please tell me what wavelength you used. Such experience would save me some effort and time.

Regards M

 

[_q12x_]

I will take a look later but more likely tomorrow morning when I get up.

Could you clarify something for me please? Have you actually done a 1W IR led shining on your hand and then reflected back to a photodiode? I know you did a beam interrupter system using visible light LED and PD. If you did how did you arrange the IR led and photodiode at one place? Also please tell me what wavelength use used. Such experience would save me some effort and time.

Regards M

It was a theory I had some couple of reply ago. But you didnt read all I wrote before. I did not made any attempt before. It just crossed my mind (while discussing it with you here in forum) to use 1W IR led and also there are 100W IR leds as well and it is a good idea to try it.

 

[marconi]

It was a theory I had some couple of reply ago. But you didnt read all I wrote before. I did not made any attempt before. It just crossed my mind (while discussing it with you here in forum) to use 1W IR led and also there are 100W IR leds as well and it is a good idea to try it.

How do you know I did not? In your #244 you wrote 'I already find the solution for IR problem.' You have not then found the solution: you have an idea on what the solution might be.

 

[marconi]

[Remote Control Transmitter and Batteries Built in one day]
Here is 1 day of very hard work and very good results.
I apologize for a very long movie 21min.
But you will see in it how it behaves on the breadboard and how is in my hand. Also some photos of how was built, and also my "3d printing" method I used. I hope I keep you interested in it to actually watch it.

Thank you for your help so far.

I refer you back to my #231, 232, 238 and 240.

The data input to the Tx and the data output of the Rx chips are two state signals - logic signals. Being logic signals they have a specification for what voltage range represents a 0 and what voltage range represents a 1. To help you further - the data input and output can be connected to TTL or CMOS logic gates. The currents which flow during a 0 or a 1 between gates are small - mA or lower. This makes them vulnerable to pick up unless care is taken.

Logic gates have rules on how they are to be used. For example inputs should not be left floating and outputs can only sink or source so much current before the voltage goes outside the range for a 0 or 1.

If you connect one electronic circuit to a point in an another electronic circuit operating with small currents you will inevitably have some impact on the operation of either or both circuits - sometimes it will not be noticeable and other times it will to the point of changing one, the other or both circuit's operation. When this happens the signal passing across the interface between the two circuits will not be what you thought it would be. To prevent one circuit disturbing another interfaces have to be carefully studied and often a buffer circuit designed and introduced between them. I mentioned this earlier.

When a mechanical switch or finger as you are using is used to generate a voltage change to represent a 0 or 1 its output is often unsuitable to be directly connected to a logic gate input because of contact bounce.

Finally - for now - data circuitry can be as vulnerable to interference and noise as analogue unless care is taken to have robust voltage levels representing logic states and transitions between states are very quick and without any bouncing between states. The voltages representing a 0 or 1 should not be near the upper threshold for 0 or lower threshold for 1 to avoid interference and noise 'pushing them into the separation band voltage ranges when a 0 or a 1 is undecidable by the logic electronics a situation which will produce random 0s or 1s.

I suggest you use your oscilloscope and examine the nature of the signals you are creating eg: at the data input to the Tx and at the ouput of the Rx. You will then have an image in your mind of their waveform and suitability and what is required to clean them up and make them robust and thence reliable for data transfer without error.

 

[_q12x_]

I refer you back to my #231, 232, 238 and 240.

The data input to the Tx and the data output of the Rx chips are two state signals - logic signals. Being logic signals they have a specification for what voltage range represents a 0 and what voltage range represents a 1. To help you further - the data input and output can be connected to TTL or CMOS logic gates. The currents which flow during a 0 or a 1 between gates are small - mA or lower. This makes them vulnerable to pick up unless care is taken.

Logic gates have rules on how they are to be used. For example inputs should not be left floating and outputs can only sink or source so much current before the voltage goes outside the range for a 0 or 1.

If you connect one electronic circuit to a point in an another electronic circuit operating with small currents you will inevitably have some impact on the operation of either or both circuits - sometimes it will not be noticeable and other times it will to the point of changing one, the other or both circuit's operation. When this happens the signal passing across the interface between the two circuits will not be what you thought it would be. To prevent one circuit disturbing another interfaces have to be carefully studied and often a buffer circuit designed and introduced between them. I mentioned this earlier.

When a mechanical switch or finger as you are using is used to generate a voltage change to represent a 0 or 1 its output is often unsuitable to be directly connected to a logic gate input because of contact bounce.

Finally - for now - data circuitry can be as vulnerable to interference and noise as analogue unless care is taken to have robust voltage levels representing logic states and transitions between states are very quick and without any bouncing between states. The voltages representing a 0 or 1 should not be near the upper threshold for 0 or lower threshold for 1 to avoid interference and noise 'pushing them into the separation band voltage ranges when a 0 or a 1 is undecidable by the logic electronics a situation which will produce random 0s or 1s.

I suggest you use your oscilloscope and examine the nature of the signals you are creating eg: at the data input to the Tx and at the ouput of the Rx. You will then have an image in your mind of their waveform and suitability and what is required to clean them up and make them robust and thence reliable for data transfer without error

Very good explanation and solution making ! I am exactly at this stage right now, modifying the output Rx with a new circuit (like a buffer) to drive normally the wing leds. Big problems so far, but I will take care of them, 1by1. Hopefully. Thank you for your very nice discussion here. Much appreciated.