Search found 376 matches

by L. Daniel Rosa
Thu Sep 18, 2008 10:11 am
Forum: General Discussion
Topic: charlieplex buttons caveat
Replies: 18
Views: 5333

Thank you jollyrgr. I patched the image into the first post.
by L. Daniel Rosa
Wed Sep 17, 2008 6:27 pm
Forum: General Discussion
Topic: charlieplex buttons caveat
Replies: 18
Views: 5333

Have a schematic we can take a look at? Oops! I should have included that in my original post, sorry. I'm at the library right now. I'll modify my original post and null this one when I get that appended- or maybe attach it to this one. added: I have it now, but no idea how to upload it to the foru...
by L. Daniel Rosa
Wed Sep 17, 2008 5:21 pm
Forum: General Discussion
Topic: charlieplex buttons caveat
Replies: 18
Views: 5333

charlieplex buttons caveat

I finally got a six button array to read correctly (problems with my code), and came to realize something that wasn't immediately apparent on paper. When two or more buttons are pressed that put the anode of one diode to the cathode of another, then a phantom third is read as well. The way around th...
by L. Daniel Rosa
Wed Jun 11, 2008 1:04 pm
Forum: General Discussion
Topic: logic probes
Replies: 6
Views: 1630

Do you care to expand on that, Dean? CMOS and TTL are 99.97% of the logic levels that I'm aware of. As substandard as the functions may be, it is a tool that may be all that a neophyte can afford. Come to think of it, the frequency counter that I paid good money for isn't much better. Now that I thi...
by L. Daniel Rosa
Mon Jun 09, 2008 5:33 pm
Forum: General Discussion
Topic: logic probes
Replies: 6
Views: 1630

I looked on his website before and all I noticed was the tips and tricks, many of which didn't impress me much. I followed that link and and wow- that's a crescent screw hammer! More than half of what that thing does is degraded only by the fact that the display is limited to four digits. That's one...
by L. Daniel Rosa
Sun Jun 08, 2008 3:29 pm
Forum: General Discussion
Topic: Battery Tab Welder
Replies: 2
Views: 1146

And lastly, are SCR's of the same current rating about equal in other specs? No. First off there is the voltage rating, of which several are available for nearly any package. Then there is the power dissipation capability which is often consistent to the package and current rating, but not always. ...
by L. Daniel Rosa
Tue Jun 03, 2008 3:32 pm
Forum: General Discussion
Topic: a micro sidereal clock?
Replies: 5
Views: 1684

One of the applications is astronomy. Sidereal noon references a point outside the solar system (ideally infinite) so after one sidereal day, we're once again in a good position to view an extrasolar body.
by L. Daniel Rosa
Sat May 31, 2008 6:41 pm
Forum: General Discussion
Topic: Workbench Design-- Ideas?
Replies: 14
Views: 3919

Room available= corner room of basement with freezer and a few boxes, about 7'*17'. Materials available= lumber store about 3 miles away. Using 2 8' 4*4s, 3 8' 2*6s and 1 sheet of 3/4" plywood I built a workbench the full width at the far end of the corner room in the basement. Today's cost, about $...
by L. Daniel Rosa
Mon Apr 21, 2008 3:34 pm
Forum: General Discussion
Topic: Counter Displays
Replies: 15
Views: 3280

Dean, I'll probably do that on one of the later editions. The switchover frequency is the square root of the operating frequency, so below 1kHz (4MHz clock, 1MIPs) I'll get better resolution as an intervalometer.
by L. Daniel Rosa
Sun Apr 20, 2008 1:39 pm
Forum: General Discussion
Topic: Counter Displays
Replies: 15
Views: 3280

Funny you should mention this. One of the (many) projects on my list is a frequency counter. I plan on making mine as a "backpack" to use a 2*16 LCD. It would be limited to 50MHz due to the nature of the microcontroller's input, but could use a prescaler. The primary function would be simple enough....
by L. Daniel Rosa
Sat Apr 19, 2008 11:51 am
Forum: General Discussion
Topic: Blue transfer paper
Replies: 21
Views: 3895

Surface preparation is _everything_. Wash the sink thoroughly. Use dish detergent with no moisturizers or lotions, preferably no perfumes either. Use hot water and a new scotch pad, with no sponge/cleanser/powdery junk attached- just a plain scrubby. Lightly scrub lengthwise, then crosswise. You're ...
by L. Daniel Rosa
Thu Mar 13, 2008 5:49 am
Forum: General Discussion
Topic: Dim LCD
Replies: 2
Views: 906

I have, but only when the supply voltage was low. I'm lazy and run off 4*AA (NiMH) without regulation.
by L. Daniel Rosa
Tue Mar 04, 2008 11:00 am
Forum: General Discussion
Topic: cell batteries
Replies: 4
Views: 1552

Sorry Hacklesup, spare batteries are considered weapons (explosive devices) on airplanes.
by L. Daniel Rosa
Tue Mar 04, 2008 10:56 am
Forum: General Discussion
Topic: Dual intensity LED
Replies: 13
Views: 2619

Not nust cadillac. I see it on bmw and volkswagen. I think I saw LED lights on a lincoln, judging from the way it lit up but I didn't see it flicker. What's with this lousy engineering anyways? How hard is it to feed the array with DC? Maybe the bean counters pulling out unnecessary components are c...
by L. Daniel Rosa
Fri Nov 30, 2007 8:34 pm
Forum: Up For Grabs
Topic: does anyone still use reostats ??
Replies: 4
Views: 3118

Wow! Imagine the uses- L-pad, active current control selector, or just plain ol' dimmer for a low voltage lamp.

What values ya' got, I think I'm interested in a few- but I don't want to hog them all.