2mm pinhole LED's for 1.5v pedals

[LucifersTrip]

I've been using the red 2mm "pinhole" led's for all my 1.5v fuzzes



...but a 1.5v battery will not light the other colors I've tried (yellow, blue, green) since they all need a minimum of 1.6v - 1.8v

Does anyone know of another color (not white) or maybe another type of led that can be lit with a 1.5v battery? If so, where can I find em?

thanx

[smallbearelec]

I have a perfboard layout done for an FZ1-A project and am working on the build-it-this-way article. On R. G. Keen's suggestion, I chose to power the thing with a 9-volt battery and stick in a diode regulator that drops the voltage to the board. The basic idea is in the lower right of the schem in here:

http://www.smallbearelec.com/Projects/FZ-1A/FZ-1A.htm

I have fleshed this out in the version on my bench--It's NPN, added a schottky diode on the input for reverse power protection and powered the LED driver from the 9 volts. Works, and the voltage will be stable as the battery ages. I hope this is some help.

SD

[LucifersTrip]

I have a perfboard layout done for an FZ1-A project and am working on the build-it-this-way article. On R. G. Keen's suggestion, I chose to power the thing with a 9-volt battery and stick in a diode regulator that drops the voltage to the board. The basic idea is in the lower right of the schem in here:

http://www.smallbearelec.com/Projects/FZ-1A/FZ-1A.htm

I have fleshed this out in the version on my bench--It's NPN, added a schottky diode on the input for reverse power protection and powered the LED driver from the 9 volts. Works, and the voltage will be stable as the battery ages. I hope this is some help.

SD

Thanx much for the info. I have definitely considered doing something like that for some projects, but I have to admit that the fun is in actually using a 1.5v battery...It also takes up less space in the enclosure...and similar to possible cool sounds you'd get from a dying battery with a normal 9v fuzz, I enjoy the same with the 1.5v ones. My Sunn Buzz is still the same with a 1.2v that's been in there about a year. I'm waiting for it to sputter...

thanx again

[defaced]

Thinking out loud here, could you stack two 1.5v batteries in series, and pull the circuit voltage from the junction of the two, but light the LED off of the 3v supplied by the two batteries in series?

[LucifersTrip]

Thinking out loud here, could you stack two 1.5v batteries in series, and pull the circuit voltage from the junction of the two, but light the LED off of the 3v supplied by the two batteries in series?

That  would defeat the purpose of using a single 1.5v battery...There will always be a way of lighting any color 2mm pinhole led if you use a power supply 1.6-1.8v or greater,

[gmoon]

You could try the "joule thief" circuit, that clever little voltage booster...

Although it's an oscillator, so that might be a problem.

[defaced]

Just looked at Mouser, you shouldn't even be able to light the red LEDs you have if I'm searching right - all of their LEDs have an operating voltage of 1.6v or higher.  Can you post a part number or link to the datasheet of the devices you're using? Also, what is the actual voltage of a new 1.5v battery?  I bet it's a touch higher which is helping you out. 

[earthtonesaudio]

You need a DC-DC converter to put out a higher voltage.  The "joule thief" is one way, but there are many others.  http://www.muzique.com/news/not-a-joule-thief/

[LucifersTrip]

You need a DC-DC converter to put out a higher voltage.  The "joule thief" is one way, but there are many others.  http://www.muzique.com/news/not-a-joule-thief/

Thanx...that looks like a cool alternative. Now if I could only find a place that sells em in quantities less than 3000. Do you have have any idea
what size* that inductor is? .....or what the battery drain is...

*brown, black, brown, gold = 100uh?
http://www.pronine.ca/indcode.htm

thanx much

[LucifersTrip]

Just looked at Mouser, you shouldn't even be able to light the red LEDs you have if I'm searching right - all of their LEDs have an operating voltage of 1.6v or higher.  Can you post a part number or link to the datasheet of the devices you're using? Also, what is the actual voltage of a new 1.5v battery?  I bet it's a touch higher which is helping you out. 

http://www.futurlec.com/LED/Red_2mm_LED.shtml

It's still lighting in my Sunn Buzz for nearly a year, but I haven't checked the battery recently...

[jasperoosthoek]

I've been using the red 2mm "pinhole" led's for all my 1.5v fuzzes



...but a 1.5v battery will not light the other colors I've tried (yellow, blue, green) since they all need a minimum of 1.6v - 1.8v

Does anyone know of another color (not white) or maybe another type of led that can be lit with a 1.5v battery? If so, where can I find em?

thanx

The physics doesn't allow it. Only red LEDs have a band gap low enough to emit at 1.5V. The voltage is directly related to the band gap. Higher band gap takes you towards the other side on the visible light spectrum. There is nothing 'before' red, well nothing...

There is one type of LED that would emit 'light' at that voltage which is an infrared emitter but you'd need night vision goggles or a CCD camera to see it.



In theory it would be possible to power convertor to get a higher voltage. But what runs on a 1.5 volts battery nowadays that would need it? Maybe something like a pocket calculator. The only thing I got is a '50s pensil size signal generator (injector/circuit fault seeker) with two germanium transistors .

[LucifersTrip]

Does anyone know of another color (not white) or maybe another type of led that can be lit with a 1.5v battery? If so, where can I find em?

The physics doesn't allow it. Only red LEDs have a band gap low enough to emit at 1.5V. The voltage is directly related to the band gap. Higher band gap takes you towards the other side on the visible light spectrum. There is nothing 'before' red, well nothing...



In theory it would be possible to power convertor to get a higher voltage. But what runs on a 1.5 volts battery nowadays that would need it? Maybe something like a pocket calculator. The only thing I got is a '50s pensil size signal generator (injector/circuit fault seeker) with two germanium transistors .

...and that explains why I'm stuck with red. Thanx much for the logical answer.

I like the solution that earthtonesaudio gave. I just need to find that chip in reasonable quantities.

Another way I found was this:
http://www.metacafe.com/watch/943296/one_aa_battery_led_lamp/

but that uses a ferrite coil

thanx again

[R.G.]

Too bad CMOS doesn't run on 1.5V. A  CMOS pump to pump 1.5V to 3V would be perfect.

As noted, the semiconductor physics do not allow LEDs to run on less than about 1.5V. There were a very few early IR and dim red LEDs that got down to 1.2V, but I don't know if they're even made any more in that style. Certainly not in your preferred package.

In any case, you're stuck with an up-verter if you demand that the battery itself be 1.5V. Whether the up-verter is a capacitor charge pump or an inductor current pump, it will have to convert 1.5V to enough to power the LED.

Here's a thought - use two 1.5V batteries and use the *LED* as the voltage regulator to run the circuit at 1.5-1.6V.   

[LucifersTrip]

In any case, you're stuck with an up-verter if you demand that the battery itself be 1.5V. Whether the up-verter is a capacitor charge pump or an inductor current pump, it will have to convert 1.5V to enough to power the LED.

Does the inductor current pump mentioned above & pictured below,

drain the 1.5v battery much quicker?  I've never worked with inductors...Is that 100uH?

Here's a thought - use two 1.5V batteries and use the *LED* as the voltage regulator to run the circuit at 1.5-1.6V.   

A cool idea...tho, not as much fun with 2 and both will not fit in my enclosure...

thanx

[LucifersTrip]

Too bad CMOS doesn't run on 1.5V. A  CMOS pump to pump 1.5V to 3V would be perfect.

Unless I misunderstood, there is actually a use for CMOS for this application:
http://www.discovercircuits.com/H-Corner/led-flasher.htm

"This electronic circuit uses only a single inexpensive C-MOS IC and flashes the LED for a full year on a single 1.5 volt AA alkaline battery cell. "

The author who linked to that article said that you can make the LED flash fast enough that it can be used as an indicator.

...and yet another method the same author mentioned, and said was a better solution is called a "Switched Capacitor Voltage Converter"
http://www.national.com/mpf/LM/LMC7660.html#Overview

But this is starting to go over my head...haha...I'll stick with a few old ge transistors.

[R.G.]

Unless I misunderstood, there is actually a use for CMOS for this application:
http://www.discovercircuits.com/H-Corner/led-flasher.htm
"This electronic circuit uses only a single inexpensive C-MOS IC and flashes the LED for a full year on a single 1.5 volt AA alkaline battery cell. "

Nope, you understand. I just remembered the old CD4000 series minimum voltage. Fairchild says their 74AC line works down to 2.0V on the datasheet, and the author of that article apparently got it to work down to 1.5V.

Kewl. That'll do nicely. You may have to select the CMOS, but if it works, great.

...and yet another method the same author mentioned, and said was a better solution is called a "Switched Capacitor Voltage Converter"
http://www.national.com/mpf/LM/LMC7660.html#Overview

And once again, s'wat I get for just remembering datasheets instead of looking them up. The 7660 does indeed say it works down to 1.5V. Again, kewl, that'll do it.

[alparent]

Does the inductor current pump mentioned above & pictured below,

drain the 1.5v battery much quicker?  I've never worked with inductors...Is that 100uH?

http://www.google.ca/url?sa=t&source=web&cd=1&ved=0CBYQFjAA&url=http%3A%2F%2Fwww.diodes.com%2Fdatasheets%2FZXSC380.pdf&ei=n2mTTe25FYuutwfG95xz&usg=AFQjCNG2JdFvx4yZX7ZfsEeCYZH0usizDw

Look at page 6