[Elecraft] [MM] The W1 LED Experiment

[Bill Johnson]

Joel,

Do you have the part #'s as I note there are a couple different in each
color?  I note these are round versions and I wonder if these are difficult
to line up in the display due to any manufacturing differences.  Do you have
a Picture of your finished product?

73,

Bill
K9YEQ
K2 #35; KX1 #35; K3 #1744; mini mods


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joel Curneal
Sent: Thursday, March 05, 2009 4:22 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] [MM] The W1 LED Experiment

Has anyone else tried high intensity leds in their W1?  I replaced the leds
in my W1 with high intensity red,  yellow (amber), and green leds from
Sparkfun Electronics.  A pic can drive them to a much higher light output
without any other changes to the W1 circuit board.  The light output from
the different colors is almost the same on a stock W1 board.

Joel,  N1JEO

----- Original Message ----- 


> I apologize for taking so long to conduct the LED experiment and get
> back with everyone interested. I had some lead times on parts I ordered
> not to mention getting some time to run everything through. I must
> mention first that I had to do numerous swaps of different LEDs and
> resistor packs and this simply would not have been possible to do in a
> timely manner without using my new Hakko 808 desoldering tool. I'm sure
> I would have damaged the W1 PCB trying to do it manually over and over
> again. That thing was worth every penny I paid for it.
>
> The slight differences in forward voltages of the various LEDs played no
> appreciable role in current consumption. So I'll just list the 3
> resistor pack values I used. I did look up the LM78L05 regulator spec
> sheet and found out it will produce up to 100ma output current. The
> current W1 design operates at far less than that. The LEDs are probably
> pulse width modulated (or simply polled) by the PIC also so the current
> draw per LED seems to be about half of what you would calculate with a
> voltage of around 3v and the resistor pack value.
>
> Here is some of the data:
>
> W1 idle current: 13.8 ma
>
> Current draw regardless of LED type per resistor pack value (18 out of
> 20 LEDs lit):
>
> 2.0k - 27.5ma
> 1.0k - 39.3ma
> 470  - 63.0ma
>
> I wanted to try an 810 or 680 ohm resistor pack, but could not get them
> in time from Digi-Key. As I personally wanted to stay within the 50ma
> range, the 1.0k value works for me. Like I said, to my eyes in a well
> lit environment, this value seemed to work fine with the Lumex LEDs
> although the Avago red LEDs were a hair brighter.
>
> Part numbers:
> My configuration:
>
> All Digi-Key part #'s
>
> Lumex Red 2x5mm LED    - 67-1047-ND
> Lumex Yellow 2x5mm LED - 67-1050-ND
> Lumex Green 2x5mm LED  - 67-1046-ND
>
> 
>
> 73,
> Dave W8FGU
>