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 ----- From: "Dave Van Wallaghen" <w8...@comcast.net> To: "Bill Johnson" <b...@creeksidecomputing.com> Cc: "'Jack Smith'" <jack.sm...@cliftonlaboratories.com>; "'Ken Kopp'" <k...@rfwave.net>; <elecraft@mailman.qth.net> Sent: Thursday, March 05, 2009 2:51 PM Subject: [Elecraft] [MM] The W1 LED Experiment > 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. > > In the end, as others have pointed out here, even though I used LEDs > with similar specs as used in the existing W1 design, there are vast > differences in brightness when placed side by side with each other. I > was looking for the right combination of LEDs and resistor packs to > obtain a good level of illumination as well as balanced brightness among > all of the LEDs and keep the current consumption as low as possible. All > of the LED part numbers and current measurements will be listed at the > end of this message. > > I did order the Avago LED from Digi-Key specified by Elecraft just to > make sure the it was in fact the same and it was indeed the same LED > used in the current W1. Despite the spec sheet, it is much brighter than > any of the other LEDs I tested. Anyway, I went down the same road that > Doug Joyce did and ordered a green, yellow and red set of similar LEDs > from Lumex. I then ordered a number of different resistor packs to > replace RP1 & RP1 with values of 2.0k, 1.0k and 470. These LEDs were > much too dim with the existing 2.0k resistor packs installed. > > I did manage to come up with the combination Lumes LEDs and 1.0k > resistor packs that satisfied my requirements. They are still a bit > dimmer than the existing red LEDs but when placed side by side, I could > not really see that much of a difference with my eyes. I did drop the > resistor packs down to 470 ohm and they were certainly bright enough, > but the current consumption increased by more than double of the > designed consumption. > > Still somewhat confused, I did manage to find similarly spec'd Avago > LEDs from Mouser that had part numbers similar to the red ones used in > the W1. So I ordered those and installed them (along with the original > 2.0k resistor packs) and much to my dismay, the green and yellow LEDs > were much dimmer than the red. > > My test setup consisted of using my K2 into a coiled wire antenna to get > a > 5:1 SWR when putting 1 watt into it through the W1. This got 18 of > the 20 LEDs lit (trying for all 20 often switched the W1 up to the next > power scale). I used a 13.5v bench supply and put a DMM in line to > measure the current consumption during each iteration. > > 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 > > 1k resistor pak 10 pin - 770-103-R1KP-ND > > Other values tried: > 1.5k resistor pak 10 pin - 770-103-R1.5KP-ND > 1.2k resistor pak 10 pin - 770-103-R1.2KP-ND > 470 ohm resistor pack 10 pin - 770-103-R470P-ND > > Avago red LED used in W1 - 516-1281-ND > > Avago green and yellow LED's - Mouser Part #'s: > Avago Green 2.5mm LED - 630-HLMP-S501 > Avago Yellow 2.5mm LED - 630-HLMP-S301 > > I hope this helps anyone looking to put a colored SWR scale on their W1. > This is certainly not a sanctioned change by Elecraft, in fact, I don't > know if anyone has even talked to them about it. So all of the usual > disclaimers about destroying your equipment apply ;-) > > 73, > Dave W8FGU > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
