hi guys i'm messing around with leds again.. ::)
heres what i want to do..5 leds, mono/guitar input..
o o < o > o o
centre on , 2 left/2 right...that react to louder strum..
i'm looking for a tiny circuit (for use with guitar input) preferably transistor..no ic, (it needs to be as small as possible.. ;)
any ideas?..
http://www.techlib.com/electronics/bargraph.htm (http://www.techlib.com/electronics/bargraph.htm) you could also use a 4049 but be aware of the different pin out.
Rob you'd love LM3914.
Quote from: frequencycentral on July 01, 2012, 12:14:58 PM
Rob you'd love LM3914.
Rick-Would R4 in this example be used to calibrate the circuit? For example, in a given application, I might want LED #8 to light up when the audio signal reaches a point that it would begin to cause undesirable distortion. So would I calibrate it by playing the audio signal at the level where it starts to sound "bad" and adjust R4 to where the 8th LED just starts to turn on? Sorry if the question doesn't make sense. :)
(http://i1160.photobucket.com/albums/q485/jdansti/e8a18a5a.jpg)
Hey Rob,
I didn't understand if you need LEDs couples (2-4, 1-5) lighting simultaneously or if they are 5 independent LEDs, anyway, you may split/adapt these comparators
(http://www.circuitstoday.com/wp-content/uploads/2008/03/led-volt-meter.jpg)
I think doing it with transistors would take more parts or PCB room, even subbing trimmers with fixed resistors...
(http://4.bp.blogspot.com/-5aSpXpZCZ0Y/TudxWVk40mI/AAAAAAAAAQk/QYheyT0Gr7E/s1600/LED+Music+Light+Circuit+Diagram%252C+Image.jpg)
BTW
Quote from: deadastronaut on July 01, 2012, 11:09:16 AM
hi guys i'm messing around with leds again.. ::)
LEDs are amazing....
ever think put one under those lovely footswitch white washers?
:icon_mrgreen:
The LM3914 simplifies the LED driving considerably, but you'll need some sort of rectification or envelope extraction for any of these. That could be as simple as a single diode and resistor though.
My vote would be for a AN6884...
http://www.e-ele.net/DataSheet/AN6884.pdf
(it's about as 'low parts count' that you can get for VU meter)
It only needs 2 caps, one resistor & a trimpot (for sensitivity) .....connect up 5 your leds, feed it a signal & you're off to the races (though you'll need a buffer if feeding a raw guitar signal as its inpunt impedance is quite low)
Not the easiest of parts to source nowadays, but available here...
http://www.cricklewoodelectronics.com/Cricklewood/product.php?productid=10017&cat=0&page=1
It's what I used in my LED sustainer driver...
http://www.youtube.com/watch?v=xXB92cSQi8E
About a year ago, I coded up a VU meter in software (a PIC)....for a mock LED pickup (6 LEDs) that has about 8 patterns (sound to light, chaser patterns such as knight Rider etc!) though going this way is enough to make the sanest of souls totally barking mad.....never again.
Edit: Doh.....just re-read that you want it to move from the centre outwards (that ain't much resolution ....2 LEDs either side of centre!) ...but rather than delete my input, I'll leave it here for others who might want a more traditional VU meter & find this thread via a search!
If you end up going with the LM391x ICs, it is worth noting that the 3914 is linear, the 3915 is log (3db/oct), and the 3916 is VU.
There are a couple of dedicated calculators out there for these ICs that I can't seem to find, and don't have permission to distribute. I have a couple for the 3914, but wasn't able to find one for the 3915 or 3916. If you really need 'em, I can zip and email.
Mike
(http://dl.dropbox.com/u/85489814/Photo%20Jul%2001%2C%2010%2030%2058%20PM.jpg)
i can't see how that particular circuit would do what rob wants.
i think rob wants the centre led of the 5 to come on fIrst, then the leds either side of centre (as the signal gets larger) & finally the other LEDs (with the signal at its largest).
With VU meters, normally comparators are involved (one needed for each level 'step'), which involves a fair amount of supporting components.
^ yep thats it.. centre on, 2 left/ 2 right...pulsing outwards...(looks like a cool chip, cheers man :icon_cool:)
wow a lot of choice, i do have a 3915...i just thought i may be able to get away with using something smaller/simpler.., but like fender3d said probably end up with more components anyway..
(:fender3d : no way ;) )
i was messing around with the good ol 386 sound to light last night, and nearly got a faux vu...by increasing the left/right resistors..
but i'll defo take a look into those other ways...cheers guys.. :)
edit: i'll dig my 3915 out for now and see how that looks...
oops i have a 3914 , not 3915.... ::)
http://www.eleccircuit.com/wp-content/uploads/2010/11/VU-meter-10-pieces-using-ic-LM3914.jpg
i tried this circuit,with 10 leds for now, but its behaving weird...its lighting up by itself going up n down regardless of guitar input.. ???
does it need an input buffer or something, or shouldit be ok as is?...
edit: i'm guessing what alex said!..
anyhow: i just bought AN6884's, got 10 for £4.00 tayda...free delivery..they look ideal. cheers G. ;)
Just to clarify my above drawing, the "LO" string would contain the LEDs immediately left and right of center, and the "HI" string contains the outermost LEDs. Note the "HI" string contains an extra diode (could be Si or Ge) so that it requires a lower collector voltage to light up.
I was assuming the center LED would only be a status indicator (always on unless the effect is bypassed), so that's why I only used two levels.
Here's another using the same principle (diode breakpoints), but for 3 levels. This one doesn't require a bias pot.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=47629&g2_serialNumber=2)
[edit: the above doesn't work quite right in the simulation. Still needs peak detection.]
ttp://www.spelektroniikka.fi/kuvat/vumittar.pdf (http://www.spelektroniikka.fi/kuvat/vumittar.pdf) there is small pcb layout for that other chip if someone needs
Quote from: Nasse on July 02, 2012, 01:08:02 PM
ttp://www.spelektroniikka.fi/kuvat/vumittar.pdf (http://www.spelektroniikka.fi/kuvat/vumittar.pdf) there is small pcb layout for that other chip if someone needs
That circuit uses the IC (AN6884), which I recommended a couple of posts back, but then re-read Rob's initial post & realised that the leds won't react how Rob want's them to. That said, the AN6884's supporting circuit could fairly easily be adapted (just use the first three LEDs - centre LED would be LED1 - & a little bit of extra circuitry to 'duplicate' LEDs 2 & 3)
Buffered Peak detector:
simulation (http://falstad.com/circuit/#%24+4+5.0E-6+16.817414165184545+50+5.0+43%0A162+592+336+592+432+1+2.1024259+0.0+1.0+0.0%0A162+752+336+752+432+1+2.1024259+1.0+1.0+0.0%0A162+672+336+672+432+1+2.1024259+0.0+1.0+0.0%0Ar+592+336+592+288+0+100.0%0Ar+672+336+672+288+0+100.0%0Ar+752+336+752+288+0+100.0%0Ad+752+224+752+288+1+0.805904783%0Ad+672+224+672+288+1+0.805904783%0Ad+672+224+752+224+1+0.805904783%0Aw+672+432+592+432+0%0Aw+592+224+592+288+0%0Aw+752+432+672+432+0%0Ag+592+432+592+464+0%0AR+368+176+320+176+0+1+80.0+5.0+0.0+0.0+0.5%0Aw+512+432+432+432+0%0Ad+512+224+432+224+1+0.805904783%0Ad+512+224+512+288+1+0.805904783%0Ad+432+224+432+288+1+0.805904783%0Ar+432+336+432+288+0+100.0%0Ar+512+336+512+288+0+100.0%0A162+432+336+432+432+1+2.1024259+1.0+1.0+0.0%0Aw+512+224+592+224+0%0Aw+512+432+592+432+0%0A162+512+336+512+432+1+2.1024259+0.0+1.0+0.0%0A174+368+176+384+240+0+1000.0+0.1337+Resistance%0Ag+368+240+368+256+0%0Aw+384+208+400+208+0%0Aw+400+208+400+80+0%0Aw+672+224+592+224+0%0Ar+544+80+672+80+0+100.0%0Ac+672+80+672+128+0+4.7000000000000005E-7+3.6225771446095134%0Ag+672+128+672+144+0%0Aa+736+64+832+64+0+15.0+-15.0+1000000.0%0Aw+672+80+736+80+0%0Aw+736+48+736+32+0%0Aw+736+32+832+32+0%0Aw+832+32+832+64+0%0Aw+832+64+832+176+0%0Aw+832+176+592+176+0%0Aw+592+176+592+224+0%0Ar+736+80+736+128+0+50000.0%0Aw+736+128+672+128+0%0Ad+400+80+544+80+1+0.805904783%0A)
...Vary the attenuation to see how it reacts to different signal levels.
I like it ;D , just a couple of thoughts....
1. The voltage follower is biased to ground (i.e. no AC signal= 0V at the output of the buffer)....I think such biasing will result in a 'dead region', where after a period of no AC signal, once the AC signal then arrives it will need to charge up that cap from 0V to near the LED's approximate forward voltage beforethe LED will even illuminate. Probably Better to bias the input to the voltage follower to somewhere below the diode's forward voltage.
2. You might struggle to find an opamp that'll deliver the current that 5 LEDS will sink.
Quote from: Gurner on July 02, 2012, 02:48:24 PM
centre LED would be LED1 - & a little bit of extra circuitry to 'duplicate' LEDs 2 & 3...
2. You might struggle to find an opamp that'll deliver the current that 5 LEDS will sink.
Just put each outer pair of LEDs in series. That way you technically only need enough current for 3 LEDs, or about 3mA, which any opamp will do.
nice one alex: i'll give that a go later...looks ideal on the sim... :icon_cool:
@merlin: yep i'll try them in series too..
cheers guys.. :)
edit: tried it with an 072 and using 1n4148, and 1-3 leds for now...didn' get any fluctuation in light when playing guitar though!..
correct diode?
Sorry I cant add more tech info on this. About a year or so ago I was playing around with an LM3916 and was able to get it to work with a very simple setup.
Ill have to look for the pics i took of my breadboard when I had it working. I started moving it over to vero to slap inside a sonic maximizer clone I had built.
Still on the back burner but it did work with 10 leds and worked very nice or so it seemed. I could get the leds to react with a dry passive guitar signal into it alone and it would peak the leds out if i strummed really hard or subtle led reaction on light picking.
If i recall I used one low value resistor at the input pin and no buffers just very simple low parts count. Haha now I remember I accidentally knocked the circuit into a glass of coca cola and left it off to the side to dry and never went back to finish the vero.
I did test it on bread board on the output of the sonic maximizer and it worked really well. I was less knowledgeable then as I am now and I'm not very knowledgeable so ill have to revisit this. I was trying to read my way thru the schematics on the datasheet for the lm3916 and when I would try to feed the chip with the buffers they suggested I didn't get any signal or not what i hoped for(one led staying on others not lighting up or weak signal) . I think I used a 60-70r resistor and thats about it before input.
I know the info I gave is remedial just hoping it might help some one at some time. And if any of you can give correct info on using the lm3916 for guitar that would be awesome :D
Quote from: deadastronaut on July 03, 2012, 04:35:24 AM
edit: tried it with an 072 and using 1n4148, and 1-3 leds for now...didn' get any fluctuation in light when playing guitar though!..
correct diode?
When you say no fluctuation....you mean they're all lit or all unlit?
LED colour will be important (especially if using in series)..what colour LEDs are you using?
yep light up...i'm using 3mm yellow brights...
i'll try some 5mm standard leds...
ive had it setup with just the one led and then 5 in parallel too......i thought i'd be able to see a glimmer of reaction but they are full on......
i tried using a 072, 5532, 358.....same..
The size of LED shouldn't matter...and yellow LEDS should be fine for in series.
Can you confirm which circuit you are using (it should be one in the java applet)
What happens with no input to the circuit? (with no input, the ouput of the opamp should be 0V, therefore the LEDS should not be lit) ...you might want to put a high value cap in series with the input (before the pot) becuase if there's DC on the input signal, then that would cause the results you're seeing.
hi G:
yep using the java applet circuit...
no difference with input connected or not...leds on all the time..using 072
just tried with 5mm standard yellows, same....no fluctuation..
072 readings
1 2.25
2 2.25
3 0.75
4 0.00
5 3.08
6 3.31
7 5.75
8 9.08
with no input the voltage is the same 2.25...
just to confirm how i have it wired at the mo...i know i haven't the other diodes on there but i thought i'd still get a glimmer of reaction as is..
note, when i put my finger on the input (trim) it does dim...
(https://dl.dropbox.com/u/7464107/ledvu1.jpg)
which of the two opamps within the TL072 are you using here? (is pin 1 your output to the LEDS or pin 7?)
I'll assume it's pin 1 that's your output.....
Pin 3 should be at 0V with no input....so there's one problem
pin 2 & pin 3 should be exactly the same voltage as pin 3....so there's another problem. I reckon that something else could be affecting this ....so disconnect any wires feeding the LEDs from pin 1 (so the only connection that pin 3 has is back to pin 2) & re-measure.
Edit: You updated you post with your layout after I asked the above....
Re pin 3 not being 0V....what voltage reading have you on either side of that input diode?
Also lift that long black wire from pin 1 (to the LEDs) & retake your reading for pins 1,2 & 3.
diode = 0.00- 0.75
lifted wire:
1 2.32
2 2.32
3 0.78
Quote from: deadastronaut on July 04, 2012, 04:42:40 AM
diode = 0.00- 0.75
lifted wire:
1 2.32
2 2.32
3 0.78
Ok, I've just had a doh moment - the TL072 is not rail to rail (I'm so used to working with rail to rail opamps, I overlooked this). the TL072's pin 1 output
can't get down as low as 0V for a single supply configuration (i.e. when you're using 0V on pin 4) . The fwd voltage of a yellow LED is about 2V.....so therefore since the TL072 ouput can swing below 2.32V, the LEDs will
always be on.
I don't think there should be 0.78V on pin 3 though (though this is probably due to the TL072 not being 'rail to rai'l again)....if you pull the green wire into pin 3 & it's still 0.78V, then that's the problem
....you need a rail to rail opamp - both on the input & ouput side, (or a bipolar supply...to get you away for now, you could connect -9V to pin 4)
One other option is to use blue LEDs...they need 3.3V, which means they'll be biased off & might work (though then I'd be suspiscious about the other end of the swing ...ie the TL072 can't swing to 9V either!)
Like I said a few posts ago...some opamps might have a few hurdles driving the LEDs here.
pulled the green wire, measures 0.78...hmmmm...
erm...isn't -9v ground?.... ???
Quote from: deadastronaut on July 04, 2012, 04:58:52 AM
pulled the green wire, measures 0.78...hmmmm...
Then the problem here is solely the TL072 not being rail to rail.
With respect to a quick n' dirty workaround (bipolar supply)....
Quote from: deadastronaut on July 04, 2012, 04:58:52 AM
erm...isn't -9v ground?.... ???
No. Ground is 0V and -9V is erhm -9V ;D ...to get a quick -9V, find yourself another 9V battery, connect the RED wire to your circuit 0V line (your blue line on your breadboard) & the black wire to the TL072's pin 4 (but remember to remove the link you have to 0V on pin 4 at present!) ....voila instant -9V (& your opamp pinout voltages will be likely be correct then)
.ok :icon_redface: :D
edit: your editing is too quick.. ;D
tried that, led goes off now...no fluctuation...
Quote from: deadastronaut on July 04, 2012, 05:10:47 AM
.ok :icon_redface: :D
done it, no difference.. :)
if you mean you have put -9V on pin 4 (vs the former 0V you had on pin 4) ...can you now post all the pin voltage readings (just pins 1,2,3,4 & 8 )
Quote from: deadastronaut on July 04, 2012, 05:10:47 AM
tried that, led goes off now...no fluctuation...
Ok, this is correct. The LEDs are off becuase in the absence of an AC input signal...the output of the TL)72 is 0V. I touched upon this earlier, there'll be a dead region, between the AC signal arriving & the LEDs turning on (for the LEDS to run on the input cap has to charge up from 0V to near 2V...but that'll take a short while in which time the input signal might cease ...end reult - not lightage!). The reason your LEDs are not turning on is probably because you input signal is not large enough...it needs a large signal at the input (& Na low impedance one too!)
okey dokey, with battery attached as per...
1 0.00
2 0.00
3 0.00
4 -5.68
5 2.18
6 2.63
7 1.88
8 9.10
Quote from: deadastronaut on July 04, 2012, 05:18:43 AM
okey dokey, with battery attached as per...
1 0.00
2 0.00
3 0.00
4 -5.68
5 2.18
6 2.63
7 1.88
8 9.10
Pins 1,2 & 3 are correct now (it's why I don't always trust simulations!) & the reasons your LEDS are off (& not turning on) are mentioned in my post above. Rather than short pin 2 back to pin 3 (which is unity gain), you could arrange it to give you some gain (have a look at Alex's the earlier post ...the one he made immediately before his sim post....that'll amplify your voltage) The other thing that you could do is what I mentioned yesterday, arrange it so that in the absence of a signal, that it's not 0V on pin, but rather just below the LED's fwd voltage...so for yellow LEDs, rather than have 0V on pin 3 in the absence of a signal, have something like 1.7V ...then there'd be no dead region. I'm also not convinced that the brightness steps between your centre & outer LEDs are going to be that distinct, but that's for a later post!
hmmmmm....... :-\ cheers anyway...
i just found a vu circuit for lm324...but if i'm going with that i might as well persevere with the lm3914...hmmmm..
or stick with my faux/fake 386 vu...for tinyness...anyway i have ordered some of those AN6884'S, so i'll guess i'll just have to wait on them for now..
bloody simulators.. ;). :icon_mrgreen:
ooh ooh...what about this...using 1 string of leds?..and npn?
http://www.eleccircuit.com/led-vu-meter-increase/
edit:just simmed it...all come on at the same time..not vu... :)
Quote from: deadastronaut on July 04, 2012, 05:29:53 AM
but if i'm going with that i might as well persevere with the lm3914...hmmmm..
You boys sure are making a meal of this... ;)
Anyway, in case it interests you, here is a proven LM3914/3916 circuit for 9V guitar operation:
(http://dl.dropbox.com/u/57831278/LEDbargraph.jpg)
In this case it uses 10 LEDs, but you could just use the lower three steps, and put your outer LED pairs in series. To get the right sensitivity you might then want to replace R23 with a pot so you can dial down the input level.
BTW: An LED bar graph is just a bunch of LEDs in one plastic block; there's nothing clever inside.
I'm not making a meal of anything.... it wasn't even my circuit (or suggestions), I was simply helping Rob to establishing why the sim'ed cct that Alex provided gave unexpected results.
There are heaps of ways of cracking this particular nut (I went the way of my coding my own bespoke PIC because I wanted total control over the LEDs sequences & response ), but if you remember Rob's original requirement, it was low part count...& towards that, I've already suggested a solution which has only about 5 components in total..
ha ha...thats nice and tiny... ;)...its me who makes a meal of things as a confirmed dumbass ha ha ha...
but seriously, cheers merlin, ...but i'm going to wait for my AN6884'S now as they are suited for just 5 leds..it'll be nice and small too...(as suggested by Gurner)
btw OT a bit.., ive just been messing around with this circuit...i breadboarded it and it works fine with 2 parallel leds on each part too...its obviously not a vu...but its a cool and above all easy
led (chaser) effect none the less..i might use this for my project instead for now
till my chips arrive.. ::)
i used 22k's and 47uf's and 3904's...to suit my speed requirements... :)
http://www.youtube.com/watch?v=YDxLG0hWXMQ
edit this is a cool one too..
http://www.elektronik-labor.de/Lernpakete/Osterei.html
Sorry it took me so long to respond. The reason the simulation doesn't work at 9V with a TL07x is because the default power supply is +/- 15V bipolar. Just like the power supplies in op-amp appnotes are usually implied.
The ground reference in that sim is therefore the midpoint of the supplies, not the lowest point. If you swap all the GND points for 4.5V it works, even with a TL07x.
But, since there's no gain it needs a whopper signal. Here's a tweaked version that works with millivolt signals (although still should be driven by a buffered source for best results) - you could use a dual op-amp's other half for that.
sim (http://falstad.com/circuit/#%24+4+4.9999999999999996E-5+15.472767971186109+50+5.0+43%0A162+592+384+592+480+1+2.1024259+0.0+1.0+0.0%0A162+752+384+752+480+1+2.1024259+1.0+1.0+0.0%0A162+672+384+672+480+1+2.1024259+0.0+1.0+0.0%0Ar+592+384+592+336+0+100.0%0Ar+672+384+672+336+0+100.0%0Ar+752+384+752+336+0+100.0%0Ad+752+272+752+336+1+0.805904783%0Ad+672+272+672+336+1+0.805904783%0Ad+672+272+752+272+1+0.805904783%0Aw+672+480+592+480+0%0Aw+592+272+592+336+0%0Aw+752+480+672+480+0%0AR+368+224+320+224+0+1+80.0+0.2+4.5+0.0+0.5%0Aw+512+480+432+480+0%0Ad+512+272+432+272+1+0.805904783%0Ad+512+272+512+336+1+0.805904783%0Ad+432+272+432+336+1+0.805904783%0Ar+432+384+432+336+0+100.0%0Ar+512+384+512+336+0+100.0%0A162+432+384+432+480+1+2.1024259+1.0+1.0+0.0%0Aw+512+272+592+272+0%0Aw+512+480+592+480+0%0A162+512+384+512+480+1+2.1024259+0.0+1.0+0.0%0A174+368+224+384+288+0+1000.0+0.797+Resistance%0Aw+384+256+400+256+0%0Aw+400+256+400+128+0%0Aw+672+272+592+272+0%0Ar+544+128+672+128+0+1000.0%0Ac+768+80+672+80+0+4.7000000000000005E-7+1.1394944777989604%0Aa+672+144+768+144+0+15.0+0.0+1000000.0%0Aw+768+144+768+80+0%0Aw+672+48+672+80+0%0Aw+768+48+768+80+0%0Aw+768+144+768+224+0%0Aw+768+224+592+224+0%0Aw+592+224+592+272+0%0Ar+768+48+672+48+0+100000.0%0Aw+672+160+672+176+0%0Ad+544+128+400+128+1+0.805904783%0AR+368+288+272+288+0+0+40.0+4.5+0.0+0.0+0.5%0Aw+368+288+368+480+0%0Aw+432+480+368+480+0%0Aw+416+176+416+288+0%0Aw+416+288+368+288+0%0Aw+672+80+672+128+0%0Aw+512+176+672+176+0%0Aw+752+480+800+480+0%0Aw+768+144+800+144+0%0Ap+800+144+800+480+0%0Ad+512+176+416+176+1+0.805904783%0Ar+512+176+512+224+0+270000.0%0AR+512+224+560+224+0+0+40.0+9.0+0.0+0.0+0.5%0Ao+48+64+0+34+10.0+9.765625E-5+0+-1%0A)
Quote from: artifus on July 01, 2012, 12:06:30 PM
http://www.techlib.com/electronics/bargraph.htm (http://www.techlib.com/electronics/bargraph.htm) you could also use a 4049 but be aware of the different pin out.
this is worth considering if you have a 49 or 69 knocking about. the first stage can be treated as a tube sound fuzz (http://www.freeinfosociety.com/electronics/schematics/audio/pictures/craigandertontubesoundfuzz.gif) - simply add input cap, swap input r from 1m to 100k and feedback 1m r for sensitivity pot. maybe play with feedback caps to tailor sensitvity too. could even take an audio out.
Quote from: earthtonesaudio on July 04, 2012, 08:41:33 AM
The reason the simulation doesn't work at 9V with a TL07x is because the default power supply is +/- 15V bipolar. Just like the power supplies in op-amp appnotes are usually implied.
The ground reference in that sim is therefore the midpoint of the supplies, not the lowest point. If you swap all the GND points for 4.5V it works, even with a TL07x.
I'm not sure it would because if you used 4.5V as the bias for the +ve pin, then you'd have 4.5V DC on the ouput pin of the opamp = LEDs on all the time (even in series if yellow LEDs used).
I think the only solution here (ie if wanting to use a single supply opamp), is to use a rail to rail input & ouput opamp & keep the bias arrangement as is (in fact even better, tweak the +ve pin bias up a tad to be just below the fwd voltage of the LEDS in play)
ALL the ground points. Meaning the LED cathodes would go to 4.5V as well.
Quote from: deadastronaut on July 04, 2012, 08:26:24 AM
but seriously, cheers merlin, ...but i'm going to wait for my AN6884'S now as they are suited for just 5 leds..it'll be nice and small too...(as suggested by Gurner)
I have a pair of AN6884's... I'll have to keep an eye on this. I was going to use mine for IN/OUT 5-bar graphs (6, with "on" status bottom LED, if the bottom of the 5 doesn't stay lit constant). I need some kind of visual as to what I'm feeding my amp out of my chain compared to the straight signal. If it pegs the OUT, I probably bumped a volume on the BF. :icon_redface:
Quote from: artifus on July 05, 2012, 02:44:58 PM
Quote from: artifus on July 01, 2012, 12:06:30 PM
http://www.techlib.com/electronics/bargraph.htm (http://www.techlib.com/electronics/bargraph.htm) you could also use a 4049 but be aware of the different pin out.
this is worth considering if you have a 49 or 69 knocking about. the first stage can be treated as a tube sound fuzz (http://www.freeinfosociety.com/electronics/schematics/audio/pictures/craigandertontubesoundfuzz.gif) - simply add input cap, swap input r from 1m to 100k and feedback 1m r for sensitivity pot. maybe play with feedback caps to tailor sensitvity too. could even take an audio out.
i have a 4049 :)..i'll try it when i get time ;), busy busy busy...changing pups+setting up a les paul (old antoria copy, nice though) .pc fresh install for a mate, decorating, wiring lights...barrelling home brew beer...arghhhhh not enough hours in the @#$%ing day... :P
Quote from: earthtonesaudio on July 05, 2012, 09:01:30 PM
ALL the ground points. Meaning the LED cathodes would go to 4.5V as well.
the problem then is that the 4.5V 'reference' as connected to the cathodes needs to be low impedance (vs a modest impedance when used as a modest impedance Vref for input biasing for an opamp)....a low impedance 4.5V reference means a slightly higher component count (vs using good 'ole ground & a rail to rai opamp instead)
Quote from: Gurner on July 06, 2012, 03:22:54 AM
..a low impedance 4.5V reference means a slightly higher component count (vs using good 'ole ground & a rail to rai opamp instead)
How does a rail-to-rail opamp help? A TL07x can swing its output down to around 1.5 to 2V, so as long as the LEDs threshold voltage is a bit more than that, they'll turn off. You can always increase the threshold voltage further by adding an extra diode/zener in series with the output of the opamp.
Quote from: merlinb on July 06, 2012, 04:09:43 AM
Quote from: Gurner on July 06, 2012, 03:22:54 AM
..a low impedance 4.5V reference means a slightly higher component count (vs using good 'ole ground & a rail to rai opamp instead)
How does a rail-to-rail opamp help? A TL07x can swing its output down to around 1.5 to 2V, so as long as the LEDs threshold voltage is a bit more than that, they'll turn off. You can always increase the threshold voltage further by adding an extra diode/zener in series with the output of the opamp.
For a single supply opamp, we've just seen from Rob's earlier DC voltage readings with the no AC signal present, the TL072 input pin sits quiescently at 0.75V & the output pin only swung down as low as 2.2V ...this isn't low enough if you've a Red or Yellow LED connected to the opamp output. (cos the LED will always be on) a rail to rail opamp helps, becuase with no input the output can swing down to 0V = LED off.
Sure, as you've pointed out, you can work around this with a non 'rail to rail' opamp like a TL072 by *adding* stuff to compensate for the lack of rail to rail swing ability but remember.....the requirement was low component count!
righto, ive recieved my AN6884'S today....yay..
@Gurner: so i can just bread the example on page 4 of the pdf with 9v yes?....with guitar straight in?...
http://pdf1.alldatasheet.com/datasheet-pdf/view/13421/PANASONIC/AN6884.html
Quote from: deadastronaut on July 16, 2012, 11:28:38 AM
righto, ive recieved my AN6884'S today....yay..
@Gurner: so i can just bread the example on page 4 of the pdf with 9v yes?....with guitar straight in?...
http://pdf1.alldatasheet.com/datasheet-pdf/view/13421/PANASONIC/AN6884.html
this will be the point where I go oops, I've just gone back to your first post...
Quote from: deadastronaut
i'm looking for a tiny circuit (for use with guitar input) preferably transistor..no ic, (it needs to be as small as possible.. ;)
I'd overlooked the bit in bold imagined this was going to be T'ing off your guitar signal from another circuit.
unfortunately, the datasheet doesn't say what the input impedance is for the AN6884, but the cct as shown on page 4 (with the 10k pot at the input) will almost certainly load your guitar signal down ....you could try a higher value pot & hope, but if that doesn't work then it will need a simple buffer in front.
[I'll get me coat]
i'll get it for ya....and ya hat....ok i'm breading it now anyways... ;)
Quote from: deadastronaut on July 16, 2012, 11:58:13 AM
i'll get it for ya....and ya hat....ok i'm breading it now anyways... ;)
Actually, I'm off the hook (so my coat stays on it!)....becuase the AN6884 block diagram on page 1 of the datasheet, shows the 1st stage is a non inverting opamp....that'll be high impedance (therefore no loading of your signal), so all you'll need to do is have a high value input pot (vs their 10k pot...preferably 1M or 500k)
righto....
got a 500k pot on it, its not acting as a vu though, its just raising and lowering the leds as i turn the pot up/down....no fluctuation with guitar!!!
edit:
ooopppsss...had leads backwards..... :P
yayyyyyyyyyy it works.....excellent...cheers G pukka!!!!.... ;)
(https://dl.dropbox.com/u/7464107/5LEDVUMETER.jpg)
here ya go...works a treat!.... :icon_cool: :icon_cool: :icon_cool:
i rigged up 9 leds (para) to get <<<< o >>>> looks great..... :icon_cool:
hi rob, where did you connect the pot? thanks.
edd
hi edd, thats a 1M trim pot on there...
just connect a 1m pot there if you don't have a trimmer...
pin 1 means pin1 of the AN6884.. ;) Its a 9pin SIL...(iirc that terminology is correct)
In case it's not obvious....the trim is set & forget (for your gutar type)....the trim could therefore easily be substituted with two fixed resistors (thereby making the final pcb a little smaller & cheaper) - i.e. once you've got the leds responding to your liking, just measure between the wiper & each of the outer lugs to get the two resistor values you need in lieu of the trimpot
^...cool...i recommend breading it for your guitar signal... :)
a nice little addition to a pedal, board etc..... :icon_cool: :icon_cool: :icon_cool:
note: when it wasn't working properly, it was a good pot level indicator :icon_idea:....just for kicks...
> "led 1 stays on"
It isn't supposed to. Probably if you replace the 500K-1Meg input pot with a 10K, and shield away from all AC or fluorescents, it will go out.
LED 1 is glowing because the "high impedance" internal gain-stage is not so very high impedance. It weeps a DC current, up to 1uA. In a 1Meg pot that would make 1V even without signal! Which would light LEDs 1-4! Obviously your perticular chip does not weep a whole uA, because even at 500K that would light a bunch of LEDs.
Still, the number of lit-on-silence LEDs will vary with chip, temperature, pot value and setting.
This is where a buffer would be good.
OTOH, one on-LED is no big deal.
An ebay search on KA2284 brings up some prebuilt modules less than $4 shipped. Bargain!
wheres the fun in that!... ;D
that is cheap :icon_cool:, i have 9 super brights though.. :icon_eek: <<<< o>>>>
@prr i quite like the centre one on anyway...but thanks for the info.. :)
I ended up trying to make my very first pcb layout from this thread with the an6884. Used expressPCB and did 10 leds total like how you had mentioned earlier dead. I gotta say it works really nice I dont have any issues with any leds staying on or not triggering well. Its pretty much great and very responsive! love it! :icon_biggrin:
(http://i1053.photobucket.com/albums/s479/MCMustachio/IMAG2149.jpg?t=1344172213)
and heres pre assembly its the board on the right.
I will say the traces and pads where very small, didnt realise till I went to drill it after etch. I went back and fixed in expressPCB for the next time I etch one. If you want the layouts let me know. Thanks for all the info on this was awesome I love leds and vu meters!
(http://i1053.photobucket.com/albums/s479/MCMustachio/IMAG2148.jpg?t=1344172173)
Also I never had any luck bread boarding the lm3916 with an opamp in front of the input. Ive only gotten it to work with guitar straight in with a very small limiting resistor . Ill work on that more later. Thanks again for all the info guys !
^ COOL.... thats a neat little ic eh!....cheers to gurner too!... ;) :icon_cool:
Yeah its awesome I think I picked up 4 or 5 gonna have to get more, been seeing a few different circuits for it online I think one was a spec analyzer. I love these led circuits I just picked up some of those 5 meter flexible led strips now I wanna try to make a vu circuit for that!
Here's the PCB and layout images. 300 DPI should do it
(http://i1053.photobucket.com/albums/s479/MCMustachio/10LEDSplitVUOverlay.jpg)
(http://i1053.photobucket.com/albums/s479/MCMustachio/10LEDSplitVU.jpg)
5 metre strips?....nice!!!...ive got to see that... :icon_cool:
Ah if you havent seen them , they make a few diff kind the ones I got are 5050 type rgb non water proof they look like this and come on a reel at 5 meters
(http://www.led-luz.com/wp-content/uploads/2010/05/5050RGB-S-011.jpg)
they make others that have an IC every led and you can control each led separately they are called dream color some times if you wanna look for those their more expensive but look for the led strips called 6803
the 5050 are on off or fade because of the way their made and no ic controller per led.
They come in water proof too and look great behind crown molding!
usually a 5m strip takes about 2-3 amps so I'm going to try to figure out a route to control R/G/B separately from audio input .
cheers jim, looks great, keep us posted with this...i'm an led junkie too... ;D nice one!.
in my missus's infinite wisdom ::) ...we are having an 'end of the world/sci fi '' themed party on the 21st dec..
my task for this is to make a ''big'' (i mean full size 7-8 foot robot. :icon_eek: ) cheesey made from cardboard and silver foil really, to stand in my hall , ive collected various bits n bobs and boxes to make him already..
anyway to the point, using the an6884 vu meter setup, which is brilliant btw... i would like it to be sound to light, (for his mouth or eyes) (i'll diffuse the leds behind a strip of sanded perspex..)
i have a small electret mic,
http://hades.mech.northwestern.edu/index.php/Microphones
would this circuit be fine going into it?......and able to be audio sensitivity adjustable. the more sensitive and simpler the better really..(its not going to be a permanent fixture.....erm.....well maybe ;D )
2nd circuit down...
http://www.head-fi.org/t/547933/q-how-to-modify-mic-pre-amp-to-higher-gain
Quote from: deadastronaut on November 02, 2012, 08:31:46 AM
in my missus's infinite wisdom ::) ...we are having an 'end of the world/sci fi '' themed party on the 21st dec..
Cool! Thanks for letting us know! Please tell your "better half" that we'll all be there!!! ;D
That will work.
Change the 10K biasing the capsule to a 10K pot, wiper to capacitor, for sensitivity. (Scratch is OK.)
Suggestions:
Use a Darlington, change 100K to 10Meg.
Should I bring a casserole?
@jon: ok, i told her, she said she would put out some bowls of chips to nibble on then...... ;D
@paul: cheers, i used a darlington mpsa13 and 330k...2x 5 3mm blue leds......it works and looks great and is very sensitive...however, it flashes when putting a sine wave into it rather than just holding at that level..... ???
how can i smooth that out...?
re: casserole: yes please...and lots of beer!. ;)
heres the schematic i drew up..
(https://dl.dropbox.com/u/7464107/micvumeter1.jpg)
Quote from: deadastronaut on November 04, 2012, 09:02:42 AM
re: casserole: yes please...and lots of beer!. ;)
heres the schematic i drew up..
Since Paul has the casserole, I'll supply some Shiner Bock beer from central Texas. ;)
No schem shown, Rob...
As long as we're having a pot-luck supper, how about I bring dessert? Mississippi Mud Pie, anyone?
@mike:
hi mike, scheme shows up for me?...anyone else not see it?
https://dl.dropbox.com/u/7464107/micvumeter1.jpg
> it flashes
I suspect this will be acceptable for the purpose.
But let's think "why?" anyway. Put in signal. LED(s) light up, draw current. Power source sags suddenly. Q1's bias changes suddenly, it doesn't work until it self-corrects. Meanwhile loss of signal through Q1 has turned-off the LED, the current, the sag.
Mike preamps should generally have decoupling in the power line. 1K and 100uFd might be ample here.
> hi mike, scheme shows up for me?...anyone else not see it?
Bizarre... it's there, now.
> Mike preamps should generally have decoupling in the power line. 1K and 100uFd might be ample here.
?? Did you mean "Rob"? All I wanted to know was if anyone wanted Mississippi Mud Pie for afters 8)
> Did you mean "Rob"?
"Microphone preamps bla-bla". Wasn't calling you. Sorry. Too much chocolate.
Quotethey make others that have an IC every led and you can control each led separately they are called dream color some times if you wanna look for those
You mean they make those in more colors than just 'information kiosk white'?
tried the cap/resistor...no joy...
its ok for drums, it picks out the kick nice, but its quite annoying when music is playing that it just flashes constantly at a regular freq..
i tried tweaking the AN6884 10uf/10k..and the 2.2uf.....well all of it really... ::)
...i'll try a few more tweaks.......heres my plans anyway... ;)
i made it modular so i can use the bits later...no cuts either whooohooo ;)
(https://dl.dropbox.com/u/7464107/micvuMETER2.jpg)
Extra points for no cuts! ;)
BTW- Don't you think you're robot needs a voice? Maybe rig up one of those voice recorder/players from a greeting card to a motion sensor so that when someone enters, the robot greets them? When he talks, his "voice" will also activate your LED circuit which will flash as he speaks. You'll have to run your voice through one of your DIY filters when you record it to give it a "robotty" accent.
ha ha cool idea, but i don't think you'd be able to hear it above the carcass, slayer, opeth, kreator, negura bunget type thrash... :icon_twisted:
Good point. You wouldn't want your robot shouting at your guests. ;)
ok, in my quest to find a good 'responsive' vu meter i found this russian guys version of the AN6884 VU METER..
1st vid is straight an6884 circuit...
2nd vid is with opamp added...(better peak and trough)
http://translate.google.com/translate?sl=ru&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fcxem.net%2Fsound%2Flight%2Flight60.php
i'll add that to my breadboard, but i'll still need the electret mic amp too though right... :)
ive given up on the AN6884 with electret mic....just couldn't get it stable..
soooooooooooooo....
ive dug out my lm3914 vu ic....running on 9v
http://www.ti.com/lit/ds/symlink/lm3914.pdf
ive tried adding the mic preamp to it, but i really have to tap the mic to get it to respond!!!...i upped the gain to 4.7M....still weak. ???
2nd scheme down..
http://www.head-fi.org/t/547933/q-how-to-modify-mic-pre-amp-to-higher-gain
any suggestions for an electret mic input to the 3914...running on 9v..?
Power your mic with this:
(http://i1160.photobucket.com/albums/q485/jdansti/474E5030-5914-4859-B294-ADBAE81CC4AD-5929-0000059D4EA06CA6.jpg)
Then run it through an LM386 with the output to your VU?
cheers jon, ive tried various preamps to no avail....
i found a guy who did it on video, but the his link to the schematic was dead...arghhhhhhh... ::)
i just tried an opamp version and that didn't have it either...hmmmm....
i'll give that a go... ;)
edit: nope!...i can't believe a mic on a 3914 isn't more popular...unless nobody ever got it going of course. ::)...
looks like the last resort is i may have to just use the good old 386 on its own just to flash lights (sound 2 light...bummer)...i fancied a nice proper one.. :'(
Rob, the 3194 wants rather high input voltages - the first datasheet example wants 5V for full LEDs. Line level is also quite easily achieved ( Minimum Vref is stated at 1.2V so you have some overshoot over 0dB which is 0.7V, or you are aiming at Pro line level (+4dBu) which is a neat 1.2V).
So with R1 = 0 Ohms you have an internal reference of 1.25V. If you bring the mic level (which is something like 10-15mV) up to that level it should work. Amplification 100x.
cheers mike, forgive me for being a dumbass, i'm not too au fait with figures. :icon_redface:
are you saying the preamp will work with the 3914 pdf diagram?...if R1 is 'o' ohms...i.e ground?
i have the 3914 setup as in the pdf diagram (and below), but all leds are on even with or without an input on the 3914 at all.. ???
i must be missing something? ???....wouldn't be the first time.. ::)
(https://dl.dropbox.com/u/7464107/3914bollox.jpg)
They shouldn't be on. At all. The R1 I was referring to was the one as per the datasheet, in your schem it's the 1K connected to pin7.
What's the AC/DC voltage on pin 5? For all LEDs ON, that should be 1.25*(1+(3k3/1k))=5.4V (or more)
There's something wrong, either faulty wiring or components, possibly the preamp is oscillating. It did work before, but didn't have any range, right?
Have a look at the voltage at pin5 (signal in)
Dang! That's what you get for ripping through a datasheet too quickly - I meant R2 so thets the 3k3, not the 1k. If R2 is (close to) 0, then (look at the formula) you'll get 1.25V range.
I'll have to dig deeper to see what R1 needs to be to satisfy the chip (I'm guessing there's limits), dinner time now.
Edit: plus, as was said before I think, I'm not sure if you need some kind of envelope thingy - the datasheet suggests it does it internally though. Now I'm gonne eat ;P
enjoy ya dinner.... :)
i think i may have fried my mic, i reduced the 10k to the mic to 9v by mistake...arghhh and smelt burning. :icon_eek: ;D
it reads 64 ohms , but not sure if it'll still work....(i have another few on order anyway).
does that scheme above i did look ok, thats what i have on my board...?
anyway, i'll post my v's in a bit...cheers!.
pin 5 with nothing connected read 0.27v
all leds on...they go off when measuring...then back on.
> must be missing something?
My '3914 groove was decades back, but doesn't the signal input need a path to ground? Possibly 10K-100K?
Does "color organ" turn up any inneresting ideas? These will not be useful as a Level Indicator, but this is not for measurement. They were specifically designed for party use (in days when electronics were much more expensive (and sometimes rather reckless)).
@prr: its never too late too be groovy.. 8)
you were right, however my mic is definately burnt out...
so i rigged up my guitar (as schematic above, and now have a sound to light vu meter....btw i took pin 9 connection to pin 11, otherwise all led's were just on....hmmm
i put a 2.2k on the input to ground.....it responds nicely...i know ill have to adjust that when i get my new electrets, i'll see how it behaves then......probably tomorrow!.. :icon_cool:..but yep it works!!!..
now to try the 'dot' mode!....
cheers guys!!!!.. :icon_cool:
Quote from: deadastronaut on November 08, 2012, 07:06:01 AM
so i rigged up my guitar (as schematic above, and now have a sound to light vu meter....btw i took pin 9 connection to pin 11, otherwise all led's were just on....hmmm
i put a 2.2k on the input to ground.....it responds nicely...i know ill have to adjust that when i get my new electrets, i'll see how it behaves then......probably tomorrow!.. :icon_cool:..but yep it works!!!..
Glad it's working, but whut?
Pin 9 to pin 11?
pin 11 is a LED port, pin 9 is MODE (9V - graph mode, disconnect - dot mode)
Now I'm confused as to what you did.
ha ha so am i... :D
i found this 3914 'battery monitor' version....which takes 9 to 11...theres heaps of different 3914 configs out there, so its hard to find the 'right' vu one... ::)
http://www.electronics-lab.com/blog/?tag=lm3914
i tried the pin 9 on/off dot mode...no joy...weird eh!.. ???
hmmmm...being the worlds greatest dumbass again..i was looking at the datasheet for the an6884 led vu meter...which is great btw., ::)
there is a high gain amp on the an6884 , pin 8 in, pin 7 out..
http://www.e-ele.net/DataSheet/AN6884.pdf
could this be used for sound too?...in some way?..just curious,...and dumb. ;D
Quote from: deadastronaut on January 31, 2013, 07:13:08 AM
could this be used for sound too?...in some way?..just curious,...and dumb. ;D
Yeah I guess so? You'd just need to work out how to amplify your signal enough to make it register in the right range for detection. (You wouldn't want to use this amplified signal for anything else after though)
Since the datasheet refers to it as a "rectification amp" it probably rectifies and smooths an AC input, causing the output to be more like the signal's envelope than the original signal.
This is just me guessing though; give it a listen and let us know. :)
> could this be used for sound too?...
The way it's biased, it must only amp half the wave. And for smooth bargraph, you also want the cap which now gives the envelope not the waves.
So it isn't a good audio amp.
^ But possibly by adding the cap (and/or other components) and mixing the envelope with clean signal, you get a potentially desirable effect??? (Probably not but it just sounded like something to experiment with). ::)
hmmm...i'll have a poke around then...cheers. :)
meanwhile...heres a vero of the 5 led vu meter, i got rid of the trim, stuck 2 resistors in place instead, great little meter..
(https://dl.dropbox.com/u/7464107/5ledveroDA2013.jpg)
and heres a 9 led version...
(https://dl.dropbox.com/u/7464107/9ledvumeterDA2013.jpg)
and for the perf/pcb guys...
(https://dl.dropbox.com/u/7464107/5ledvumeterpcbDA2013.jpg)
and...
(https://dl.dropbox.com/u/7464107/9ledvumeterPCBDA2013.jpg)
happy retina destroying... 8)
thank you for help. my friend ask me to wind a set of pickups for his guitar and had this crazy idea. i found this thread and did some tinkering:
http://tinyurl.com/otqry24
yes, i know it is stoopid but hey, sometimes you just gotta have some fun.