3V LED Chaser project

[Ante]

Audioguru,

I think many here in the community expect a video clip soon, at least I do!

[audioguru]

Hi Guys,
It works perfectly!
My "6V" green ultra-bright LED Chaser is brighter than before and draws only 250uA from the battery between flashes and with the brightness turned down.

I replaced the 74HC14 hex Schmitt inverters IC that draws too much current at 4V to 6V with a 4584 (same as a 74C14) ordinary Cmos IC. Instead of using another transistor to boost its output current, I used a "mickey mouse" diode as a gate so the 30ms pulses from the master "speed" oscillator gates the PWM "brightness" oscillator.

I changed the brightness pot wiring to an "Ante's Special " type of wiring with diodes at each end and the inverter's output feeding the slider. Now the PWM brightness range is from almost zero (with all my lights off I could barely see the skinny pulses on my 'scope) to very close to 100%.

I'll modify my last remaining blue ultra-bright chaser the same way then MAKE A MOVIE for you guys to see and hear me singing (croak!) and all my blinkin' LEDs all around!

[audioguru]

Hi Guys,
Correction: A 4584 IC isn't the same as a 74C14, and neither are the same for an oscillator's timing as a 74HC14 that is used in the 3V LED Chaser project.

Since the 74HC14 drew too much supply current for the oscillators with a 6V supply, I wanted to use an ordinary Cmos hex Schmitt trigger IC that draws much less current. The 4584 IC that I tried made the speed oscillator run too fast, so I increased its timing capacitors, C3 and C4, from the original total value of 800nF to 1.47uF, and it is still rather fast. I don't want to make the caps even bigger 'cause those metalized-film ones are big and expensive.

So I researched  the hysteresis for all the Cmos hex Schmitt trigger ICs with a 5V supply:
- 74HC14  0.6V to 1.7V (original)
- 4584      0.25 to 1.0V (much less)
- 74C14      1.0 to 3.6V (much more)
- 40106      0.3 to 2.0V (too much variation)

The 74C14 is a good choice and the caps can be reduced to just one 330nF or 470nF one. The 4584 can be used, like I did, but the caps should be increased to a total of about 2uF.

I might post a separate project for a "6V Ultra-Bright LED Chaser".    
 

[Ante]

Hi Audioguru,

This is a lot or info, maybe it

[audioguru]

Hi Ante,
My original 3V LED Chaser project works fine.
I made a number of changes so it could use 3.2V to 3.5V ultra-bright green, blue or white LEDs, and a 6V battery. The changes are numerous so I'll post it as a new project.

I modified a 3V circuit with all the changes for the 6V circuit except it kept the original timing caps and the 74HC14 that works well with a supply down to 2V or less. I have it running beside an original one right now and they look and operate the same.  

[audioguru]

Hi Guys,
I was wondering why my original 3V LED Chaser project looks as bright as the new circuit I designed for ultra-bright LEDs and a 6V battery. The original circuit produces 15mA current pulses in its LEDs but the effective current is reduced to about 10.5mA by the max duty-cycle limit of 70 percent by its PWM brightness control. The new circuit has an effective LED current of 15mA because its "Ante's Special" PWM control can reach 100 percent duty cycle.

My first "6V" ultra-bright chaser had 24mA current pulses that were reduced to about 17mA by its original PWM circuit. The improved PWM control allows the full 24mA and it looks much brighter.

I tried reducing yhe value of the LED current limiting resistor in the original and modified 3V chasers to make them brighter and the LED current didn't increase! The 74HC4017 must be at its current limit with a supply of only 3V and must be current-limiting.

The 3V chaser's LED current (and brightness intensity) increase from 10.5mA to 15mA is a 43 percent increase which must be negligible since our vision's response to brightness is logarithmic. But the 6V ultra-bright chaser's same percentage increase in current probably overloaded my vision and created a sensation of increased brightness. They are extremely bright.

I will build all chasers from now on with the new circuit. I have a new idea of using a spare inverter to gate the chaser off for a short sleep after a few revolutions. It will double the battery's life and look more interesting. I will post my 6V ultra-bright circuit as a new project with a parts list and description. Its schematic is here:

[audioguru]

You will notice that a new capacitor has been added at the transistor. It is used to attenuate extremely narrow PWM pulses at minimum brightness. Both the original 3V circuit and the new 6V circuit need it when using ultra-bright LEDs, because they are so bright.
You should see the new 1.8V orange ultra-bright LEDs I found!  

[Ante]

Thanks for the new 6-volts schematic Audioguru, nice work!

[ibernez]

Hey everyone. Im 17 and new to electronics and this is going to be my first real project.  I play guitar in a band and I want to install this project in my guitar under the strings, and between the pickups for a little added stage wowing. Here is a picture of a guitar similar to the one I want ot put this in.--> As I said I want to put it between the two pickups(2" gap), under the strings. I planned on making a back cavity (for those who don't know what that is, it's this)--> to house the project, and drill holes for the LEDs and pots. Question #1 is, Where can I get all the parts to make this project? #2 Will the project make a hum or buzz in my sound? #3 Any advice? Thanks to any and all responses.

[audioguru]

Hi Ibernez,
Welcome to our forum.
I have been making lots of these chasers. I have made some with Ultra-Bright LEDs, and they are really bright, probably more suitable for your guitar project. The Ultra-Bright LEDs need more than 3V so I modified the circuit a bit and use 4 AA alkaline battery cells. I'll post the modified circuit soon as an 6V Ultra-Bright LED Chaser project.
You might have a whine and a buzz in the guitar's sound if the project is mounted so close to the strings and pickups. I suggest mounting the circuit and its LEDs around the bottom edge of the guitar, to avoid interference with its sound and the LEDs would be seen better away from your "strumming" hand anyway.

Since you have AOL you are probably in North America, like me. I buy my stuff on-line from www.newarkinone.com or www.digikey.com since they have almost everything in stock and have pretty good prices. You pay online with a credit card and delivery is by courier the next day.

[ibernez]

Thanks for the advice. Im looking forward to the 6V Ultra-Bright LED Chaser. I figured the LEDs would make some kind of hum. The thing is is this is what us guitarists call a "project guitar". It's all hot-rodded with special pickups and stuff. I have broken pieces of mirror all over it and the only parts that aren't covered are the area under the strings and below the two pickups. So I guess I'll put it on the lower horn. Also, I forgot to ask, I'd like to put a on/off push switch in to turn it on and off. Maybe when you make the new mod circuit, you could tell what kind and where to put that in? Thanks.

[audioguru]

Hi Ibernez,
I just finished another 3V LED Chaser. This time I used orange Ultra-Bright low-voltage LEDs and they are really bright on-axis. I also used most of the changes that are in my 6V chasers.
I added another trick to this one and probably all future chasers: the LEDs chase around and around a few times then they go dark for a few seconds, saving the battery power, then start chasing again.  

A chaser would look cool in your guitar. Maybe it won't cause interference if you mounted the circuit and LEDs inside a metal box positioned under the strings.

An on-off switch can be wired in series with one of the battery's wires.

[ibernez]

So I can use Ultrabright Low voltage LEDs? that would be great because the smaller the cavity the better. I can get copper shielding tape like this to put in the cavity. Do you think it could work under the strings with that? I think ill use the regular chaser project you made before. So can I use the "3V LED Chaser" project and just substitute with ultrabright low voltage LEDs?

[audioguru]

Hi Ibernez,
The low-voltage orange Ultra-Bright LEDs I found were in a bag marked "RED" and are "no-name-brand" from China or India. They measure about 1.8V at 20mA. They have a clear package and make a blinding light beam about 20 degrees narrow. Red and orange Ultra-Bright LEDs are usually 1.8V to 2.2V and will work fine in my original 3V Chaser project.
Blue, green and white Ultra-Bright LEDs are usually 3.2V to 5V and need a 6V circuit.

You have a good idea to use copper tape for a shield. Make sure to electrically join the pieces together and connect it with a wire to the negative battery terminal on the circuit board (ground). Maybe you can wrap the circuit inside the shield with insulating heavy plastic film to keep it from shorting to the copper tape. The battery doesn't need shielding.