Led triggered by sound

[rossw]

Spent most of the time trying to figure out the colors on resisters.

RossBot could have helped you!
It will do both, conversion from the colours to the value, and from a value to the colours.

<RossW> !resistor 4k7
<RossBot> 3-band: yellow violet red gold.    (unspecified, assumed 5%)
<RossBot> 4-band: yellow violet black brown brown.    (unspecified, assumed 1%) 

<RossW> !resistor orange white brown gold
<RossBot> 4 bands, 390.000 Ohms 5.00%

<RossW> !resistor brown black black red brown
<RossBot> 5 bands, 10.000 Kilohms 1.00%

[WooferHound]

You could probably reduce the feedback resister (R3) considerably if it seems a bit touchy to adjust.

[Mixerman]

Spent most of the time trying to figure out the colors on resisters.

RossBot could have helped you!
It will do both, conversion from the colours to the value, and from a value to the colours.

<RossW> !resistor 4k7
<RossBot> 3-band: yellow violet red gold.    (unspecified, assumed 5%)
<RossBot> 4-band: yellow violet black brown brown.    (unspecified, assumed 1%) 

<RossW> !resistor orange white brown gold
<RossBot> 4 bands, 390.000 Ohms 5.00%

<RossW> !resistor brown black black red brown
<RossBot> 5 bands, 10.000 Kilohms 1.00%

Do you have a link to this? Cant find it.
Thanks

[WooferHound]

Do you have a link to this? Cant find it.
Thanks

RossBot is available as commands on our AnotherPower IRC Chat channal
irc.anotherpower.com #otherpower
you can click the link on the Top Right-hand corner of any page

Here are the commands that are available there
http://home.albury.net.au/~rossw/irc-converter-help.html

[Mixerman]

You could probably reduce the feedback resister (R3) considerably if it seems a bit touchy to adjust.

OK, I'll give that a try, just have to move the wire and try it!


Now I understand, thanks for the link!!!

[MadScientist267]

Spent most of the time trying to figure out the colors on resisters.

RossBot could have helped you!
It will do both, conversion from the colours to the value, and from a value to the colours.

...

<RossW> !resistor brown black black red brown
<RossBot> 5 bands, 10.000 Kilohms 1.00%

Wow, wish I'd have known about that... I have the 3 + tolerance colors down, but the 4 and 5 band precision resistors irritate the crap out of me!

I really gotta play with more of the features on that thing! Can it solve world hunger? LOL

Steve

[Mixerman]

We went out and tryed it on the wifes car today! It worked!!! I could hear and see the LED light flashing as the injector fired. The LED was not very bright though. I still have the upgrade to do though.

In the video you will see me connect a brass brazing rod to the Piezo pickup. then I will turn it over a try the other side, then back again. Listen close you will hear the injector working.

http://www.flickr.com/photos/18130316@N07/7103516039/in/photostream

[MadScientist267]

You can get one of those insane bright red LEDs from RS that will help with that... They'll blind you if just flat out powered with DC, but for quick flashes, the extra brightness makes 'em show up nicely in sunlight.

Steve

[Mixerman]

Steve, I went down to the local RS and picked two Leds ( 276-0015) Package says Ultra High Brightness 10MM Red !!  Intensity: 400mcd, FW current: 20mA, FW supply: 2.4V (max).

I just swapped them out with what I had, didnt work to well. Am I missing something?

[MadScientist267]

Shouldn't be any issue with it working with the circuit; at that level, an LED is an LED. If it's predecessor worked, this one should. But, when I went and looked up the part number, one of the reviewers said something about the polarity being reversed as opposed to what was listed on the package.

With what you're doing with it, it won't hurt it to flip it around; it will either light up or it won't.

If it still doesn't, you can test the polarity/functionality any number of ways, my personal favorite is just using a CR2032 battery (the type used for CMOS backup in computers) as a power source. A 9V with a 1K resistor works well for tests in a pinch as well. If you use anything besides a lithium coin cell to test, be sure to use a resistor - it doesn't take much to smoke an LED. You don't need a resistor to test with a coin cell because they can't deliver enough current to pop it.

Another way to determine LED polarity that I typically use is usually the "dish" of the LED is negative (where the die sits). This is true most of the time; there are odd exceptions with specialty LEDs (self-blinkers, etc).

Steve

[Mixerman]

I flipped it around and it dosent work! Maybe its just me, when I look directly straight down both LEDS are much brighter. I might be expecting to much!

[rossw]

Steve, I went down to the local RS and picked two Leds ( 276-0015) Package says Ultra High Brightness 10MM Red !!  Intensity: 400mcd, FW current: 20mA, FW supply: 2.4V (max).

I just swapped them out with what I had, didnt work to well. Am I missing something?

I'd say at a guess you're missing about 15 years of technology advances.
In this day and age, nobody would call 400 mcd "ultra high brightness".

Here's a random RED LED specs I just found:
    Luminous Intensity : 12,000 mcd
    Emitted Colour : Red
    Size: Ø5mm
    Lens Color : Water Clear
    Life Rating : 100,000Hours
    Forward Voltage (V) : 1.9-2.1
    Forward Current (mA):<= 30
    View Angle: About 45-55 degree.

And $5/100 including shipping doesn't make them anything special!

[MadScientist267]

I'm not sure exactly what you mean by that... but yes, due to the shape of the package, it forms a tight beam.

One way around that is sandpaper to "cloud up" the lens.

It sounds like they are working, but I can't discern whether there is an issue electronically or not. Looking back on the schematic, it's calling for a bipolar supply (+/- 9V in relation to ground), so polarity of the LED is likely to matter very little. I hadn't spotted that before...

The pulses you're going to get at the LED from an injector are going to be rather short, and so will appear fairly dim simply because your eye can't react as fast as the LED. There are a few tricks for this, but none that are in the "super simple" category.

Did you get rid of the low pass filter that was in the original schematic? Since you're not measuring things that only require low frequency response (like heart beats), this is probably working against you. I'd ditch C4 just as a test to see if this has any effect on the LED's output. Of course, you're going to have to adjust the levels and all of that once the cap is gone; the response of the circuit is going to be much different.

Steve

[Mixerman]

The packaging says 16 degrees viewing angle, I'll try sanding one!

This is the plans free on line! I used these plans because it uses all the parts that come with the kit.

Yes! the sanding helped!!!!!!!!!!!!!!!

[MadScientist267]

Ok, this looks a little more like what you need. The supply here however is single ended, so polarity of the LED will come into play.

You have a full audio range (and then some) amp here, with all the basics to get you the output you're looking for.

The half of the op amp that's driving the LED has a fixed gain of about 30, and the preamp is set up with a gain of anything from unity to approaching infinity (not actually possible, but high enough to get the LED to light up, for sure!). In a nutshell, yes this thing is very sensitive if you need it to be.

You may find that you probably don't even need the 386 at all, since it's primary purpose is to drive the speaker. U1b simply taps off of the output of the 386 as it's input. While it may be providing the extra gain that the LED could need to see useful flashes of light, it's probably not necessary, and U1b (as drawn in the top schematic) can probably be connected to the "volume" pot's wiper directly instead.

If this isn't clear, let me know, I'll see about scribbling up a quick schematic.

Steve