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691  Using Arduino / LEDs and Multiplexing / Re: Getting the Teensy to recongize the LED's on: October 14, 2013, 10:53:56 pm
oh yeah, you meant reading the voltage duh....

hook one up and measure the voltage....
692  Using Arduino / LEDs and Multiplexing / Re: Getting the Teensy to recongize the LED's on: October 14, 2013, 10:53:11 pm
wow, i've not seen one of them since 1988 lol, age 7 at the top of the stairs my dad gave me a 9v battery and an LED, thinking back the 9v battery was pretty dead (he got me to taste it, very very mild) but yeah i connected the LED both ways until it lit up glowed almost changing color (obviously, too much voltage) but as the battery went dead , the LED was this type!

digitalWrite(pin,HIGH);

use a 300 ohm resistor in series to keep the current down on these old things...
693  Using Arduino / LEDs and Multiplexing / Re: Getting the Teensy to recongize the LED's on: October 14, 2013, 02:33:39 am
Each wavelength / band gap - has a certain forward voltage drop, so that's what you'd be measuring...  curious project I might have a play see what results i get...

694  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 11:38:59 pm


That's the method i'd use to amplify (via a darlington)

there are many ways of doing this job using just a few discrete components, but demanding someone build one!
695  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 11:28:52 pm
Am i to understand correctly, you have no "voltage" to be amplified?   (what's the opamp for then?)
696  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 09:39:07 pm
First stage amplifies the tiny signal from the ir detector, this gets amplified via the transistor attached image 1.

Second stage (providing a square wave is applied) and some extra (maybe) components to filter it, then lastly extending the pulse.

Pretty straight forward by the looks of it...


Moderator edit: Non-technical comment removed, <sigh> (Nick Gammon)
697  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 05:42:12 pm
I wonder Cjdelphi... If you have ANY IDEA of the photodiode current available in that circuit or the gain of the Op-Amp?.
Stretching the pulse is trivial.. A half monostable from a 40106 or a 4584 will serve nicely..
It is possible too, to use a 4069UB to do all of it with 3 sections connected as a linear amplifier 40 DB of gain can be easily realized and the remaining 3 sections can clean up and delay the pulse. The down side is that the 4069 isn't very fast because it is unbuffered..
I would suggest that in the future you supply schematics to back up your rather unusual? claims.

Doc

Amazing ignorance.

Saying this can't be done without using an ic ... and then like a pack of starving dogs attack me for suggesting otherwise lmao... i say wild more like an annoying poodle.

698  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 10:03:13 am
mike, point is you read what I say as literal, I do not mean Literal if i did i'd be listing components, they're just thoughts and yes it's possible to use just transistors to extend a pull... never made one, have you? so don't rule it out.

You ought to present your "concept" with a circuit sketch, not verbally.


I shall then.....I amplify the signal, clean it and extend the pulse, which gets fed into the IC... yup i'll have a think about it and design a circuit,
699  Using Arduino / LEDs and Multiplexing / Re: WS2811 Led strip - how many amps? on: October 12, 2013, 10:00:14 am
50 arrived yesterday ws2811, if you look closely the wafer is exposed and you can see all the colors of the spectrum (since the epoxy protects them)

but yeah 20ma per R G B 60ma per LED * 120 = 7200ma (7.2amps) or  5v *  7.2amps  36watts.

Aim for a 50watt power supply or it will run on the hot side. 5v 10amps .
700  Using Arduino / General Electronics / Re: Circuit Debounce on: October 12, 2013, 09:50:10 am
With all due respect, cjdelphi, I think you should hold off trying to answer questions until you learn a bit more about basic electricity, circuits, and current flow.

Those circuits you simulated are nothing like any of the circuits posted here.


With all due respect, stfu.
701  Using Arduino / General Electronics / Re: Circuit Debounce on: October 12, 2013, 09:47:42 am
I'm concerned with the rate of charge discharge.

Let's say you dis charge the cap by shorting, just how much current will i draw from the arduino pin? I see no resistor?

What does the capacitor have to do with the current from the Arduino pin? It is the pushbutton that is shorting the capacitor, and the Arduino is not part of that path.

Using the internal pullup, which is 20k, current is limited to 5V/20k = 250uA maximum. That only flows when the button is being pressed, and for a short time after you stop pressing it, that current decays exponentially. So what is the problem? An external capacitor will cause more current through the switch or pushbutton, not the Arduino.

Might I suggest Electronic Principles by Malvino? Or Basic Electronics by Grob?

I'm concerned with your lack of understanding my confusion, in the circuit there was no "Pull up" resistor.

Because if you had have read posts prior, you'd have seen that, now stop with the petty bullying and grow up.
702  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 09:44:32 am
Another way might be to use a dalington transistor pair or 2 transistors biased to amplify the signal then feed it through a schmitt trigger to clean the waveform up .
Sigh! - No it would not.

if biased properly so the sits off via the voltage divider, it will amplify the signal, why not? passed that 5v high (not low side of the transistor) to a not gate, or simply a buffer, and it will give a low and high edge or bypass it completey and design the  schmitt trigger..

mike, point is you read what I say as literal, I do not mean Literal if i did i'd be listing components, they're just thoughts and yes it's possible to use just transistors to extend a pull... never made one, have you? so don't rule it out.
703  Using Arduino / General Electronics / Re: Extend Pulse from Op-Amp/Photodiode combo? on: October 12, 2013, 07:09:04 am
Another way might be to use a dalington transistor pair or 2 transistors biased to amplify the signal then feed it through a schmitt trigger to clean the waveform up .

Oh yes of course using a capacitor to "extend" your pulses ill design a circuit should be simple.
704  Using Arduino / General Electronics / Re: Loud speaker under 1 inch in diameter on: October 12, 2013, 07:03:06 am
I was playing with magnet wire sometime ago and placing them on the floorboards in certsin places i was able to get the whole house to become the base speaker....

But how about a low pass filter on a resonance speaker (magnet coil rolled up against object with magnet below or above providing it all made good contact.  And a 2nd high pass to feed to  tiny tweeter even a piezo?
705  Using Arduino / General Electronics / Re: Circuit Debounce on: October 12, 2013, 04:14:20 am
http://www.gammon.com.au/images/Arduino/SwitchesTutorial/switch_tutorial6.png

Ohhh at last it's done vis a pull up resistor!

Makes sense now
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