Alt-BEAM Archive
Message #09243
To: beam@sgiblab.sgi.com
From: Bumper314@aol.com
Date: Sat, 15 Jan 2000 23:36:36 EST
Subject: [alt-beam] Re: cutting LEDs
In a message dated 1/15/00 7:57:02 PM Mountain Standard Time,
dave@solarbotics.com writes:
> You bet! Use a sanding disk - it works very well in getting it pretty flat.
> Then use a sheet of regular paper to give it a bit of extra polish.
>
What about just sand paper?
Steve
9244 Sat, 15 Jan 2000 23:39:04 EST [alt-beam] Re: D1 beam@sgiblab.sgi.com Bumper314@aol.com In a message dated 1/15/00 8:26:15 PM Mountain Standard Time, rigter@cafe.net
writes:
> You did not mention a resistor in series with the LED. Your first report
was :
> It
> works! A 74HC14 with a +4V power supply driving a LED without current
> limiting
> can probably source 50mA so the LED would be very bright for a short
time.
> Do
> you observe such a change in brightness? Have you tried a different LED?.
> Without
> a series resistor it is possible that the LED was damaged after which it
> became
> dim. A normal resistor value for that 4V supply voltage and a high
> effiiciency
> (2mA) LEDs is 470-1000ohm. For less efficient LEDs use 100ohm which will
> result
> in about 15-20mA initial current.
The LED was never bright so I didnt think it needed a resistor. And the whole
thing is VERY sensative to me. If i get within and inch of it the thing will
either get dim or turn off...VERY weird
Steve
9245 Sat, 15 Jan 2000 23:42:58 EST [alt-beam] Re: D1 beam@sgiblab.sgi.com Bumper314@aol.com In a message dated 1/15/00 8:28:12 PM Mountain Standard Time, rigter@cafe.net
writes:
> Blue LEDs have a 4V forward voltage drop! No wonder it glowed dimly. I
will
> send
> you a schematic for a D1 with a voltage doubler which will drive this kind
> of LED
> from a low voltage solar cell.
Oh....i was just trying variety...most of my LEDs I tried were red, they have
the lowest voltage drop correct? I have had this thing running on one of
those Solarbotics SMD red LEDs for about 2 hours now, but dim and like I said
in the other e-mail, I cant hardly move it. I have it in a box with the solar
cell down, and im in a low light room, but even moving the box makes the
thing freak out. I know its not due to any loose connections since the 5
other times it was doing this and on the breadboard....I just dont know
Steve
9246 Sat, 15 Jan 2000 20:48:14 -0800 [alt-beam] Re: cutting LEDs beam@sgiblab.sgi.com Bruce Robinson David Perry wrote:
>
> you can use toothpaste (i think) to polish the face, there are
> also special polishes for plastic that help with this.
A little-known secret for removing fine scratches in plastic -- brass
polish. Works far better than toothpaste. Follow the instructions just
as you would for brass. Don't try to take out deep scratches with this
method, however. You'll get tendonitis from all the rubbing.
Bruce
9247 Sat, 15 Jan 2000 23:48:37 EST [alt-beam] Re: D1 beam@sgiblab.sgi.com Bumper314@aol.com In a message dated 1/15/00 9:44:51 PM Mountain Standard Time,
Bumper314@aol.com writes:
> Oh....i was just trying variety...most of my LEDs I tried were red, they
have
>
> the lowest voltage drop correct? I have had this thing running on one of
> those Solarbotics SMD red LEDs for about 2 hours now, but dim and like I
> said
> in the other e-mail, I cant hardly move it. I have it in a box with the
> solar
> cell down, and im in a low light room, but even moving the box makes the
> thing freak out. I know its not due to any loose connections since the 5
> other times it was doing this and on the breadboard....I just dont know
But that's not to say I don't want this new circuit. I appreciate the time
you are spending on this. I am curious if I should run all the remaining
input/outputs of the 74HC14 to ground or V+. They are just floating right now
and I think that might be causing this weird behavior ...just a thought though
9248 Sat, 15 Jan 2000 20:52:09 -0700 [alt-beam] Re: cutting LEDs beam@sgiblab.sgi.com Senior That will work too if you keep everything squared up.
-Kyle
Bumper314@aol.com wrote:
>
> In a message dated 1/15/00 7:57:02 PM Mountain Standard Time,
> dave@solarbotics.com writes:
>
> > You bet! Use a sanding disk - it works very well in getting it pretty flat.
> > Then use a sheet of regular paper to give it a bit of extra polish.
> >
>
> What about just sand paper?
>
> Steve
9249 Sat, 15 Jan 2000 21:50:43 -0700 [alt-beam] Re: cutting LEDs beam@sgiblab.sgi.com Dave Hrynkiw At 09:36 PM 1/15/00 , Bumper314@aol.com wrote:
> > You bet! Use a sanding disk - it works very well in getting it pretty
> flat.
> > Then use a sheet of regular paper to give it a bit of extra polish.
>
>What about just sand paper?
Just sand paper for the whole process? Sure, if you have the patience to
grind away that much plastic. But the paper is pretty efficient at making
the surface very nice and smooth.
-Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com
9250 Sat, 15 Jan 2000 21:59:00 PST [alt-beam] Re: cutting LEDs beam@sgiblab.sgi.com "Timothy Flytcher" First of your problem is from cutting... you don't cut plastic... I start
with making a jig... take two small blocks of hard wood (anything will work
just not pine) about 2inches X 1/2 inch X 1/4 inch ... clamp them together
and drill a whole between them that is one size smaller than the LED and a
second one coaxially to a depth that allows the LED to protrude out the
amount you want to remove... clamp the LED in place using wood screws or
bolts with wing nuts...use a medle file remove the crown(using a file will
help keep it square)... almost to the wood then use 280# sandpaper(black
wet dry paper with water and soap) to remove the deep scratches then 320#
and then baking powder and a cloth with water (flannel)... then just the wet
cloth the if you still don't like the surface texture then hit it with a
heat gun to "fire glaze" the surface... DON'T USE FIRE or you will burn the
plastic and darken the surface with soot... the end product will be smother
and shinier than original ... most plastic products come coated with
non-petroleum based oil the hide the scratches... you can duplicate this
too... simply lay your finger along side your nose and then rub the
surface... finest oil around...
this sounds complicated but it is really easy ...
Timothy...
>How do you cut an LED to make the lens completely flat and still shinny? I
>keep trying but they just crack or are scratched so bad the light is barely
>visible. Anyone know
>
>Steve
______________________________________________________
9251 Sun, 16 Jan 2000 14:39:45 +0100 Re: cutting LEDs Timothy Flytcher
> >How do you cut an LED to make the lens completely flat and still shinny?
I
> >keep trying but they just crack or are scratched so bad the light is
barely
> >visible. Anyone know
> >
> >Steve
>
> ______________________________________________________
>
9252 Sun, 16 Jan 2000 14:48:48 +0100 [alt-beam] Are these caps any good? "Beam Mailing List" "Thomas Pilgaard" Hi all
I've found some large(r) caps in a danish webstore, and I'd like you to
comment on some questions I've got on their usability.
There's a 1F cap with the following specs:
1) Distcharce at 5,5V at 1mA is 3000 secs
2) Leakage is 315uA (I'm not sure how to translate so bare with me).
3) The specs says "Internal resistance (1khz) : 30" (don't know what to make
of it)
4) Physical dimensions are Height : 8mm; Diameter : 21,5mm
The same points 1 throug 4 for a .047F cap are:
1) 190 secs
2) 69uA
3) 120
4) Height 7,5; 13,5
Would you please be so kind as to enlighten me?
Cheers,
Thomas
---
"You haven't had enough coffee until you can thread a moving sewing
machine."
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