Search found 98 matches

by gadgeteer
Fri Apr 04, 2003 1:54 am
Forum: General Discussion
Topic: Digital Tv by '03
Replies: 11
Views: 1980

Re: Digital Tv by '03

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>I have seen it compared to standard NTSC and really don't see that great of a difference in picture quality.<hr></blockquote>There isn't ANY difference! You can SEE the difference if: 1. Your vision is 20/15 or better ...
by gadgeteer
Fri Mar 28, 2003 9:29 pm
Forum: General Discussion
Topic: Electronic Supplier
Replies: 5
Views: 1143

Re: Electronic Supplier

I love my flyswatter. I "juiced" by adding a capacitor to the output. When I'm messing with the car (changing oil or somethin'), a cloud of mosquitoes swarms around me (live next to a creek). BUT--- really there are only a dozen or so; the swatter takes them all out. Each dead biter kills the high v...
by gadgeteer
Fri Mar 28, 2003 2:57 am
Forum: General Discussion
Topic: Voice Recognition
Replies: 8
Views: 1450

Re: Voice Recognition

Radio SHack had a voice-recognition chip ten years or more ago, speaker independent. Only had commands like "stop", "go", "turn left", "right turn", etc. I bought two of the chips. Know anyone with real old RS stock???
by gadgeteer
Fri Mar 28, 2003 2:20 am
Forum: General Discussion
Topic: LEXPRO RE:- - -ANALOG TO DIGITAL
Replies: 4
Views: 799

Re: LEXPRO RE:- - -ANALOG TO DIGITAL

Why can't you just use a 7107 voltmeter chip, with direct-drive LED outputs? Tie a pot into your tuning dial to drive the meter input, and calibrate the meter to display the correct numbers (it's made to display up to 1.999). The numbers should be very stable and repeatable. And with the 7107 (or 71...
by gadgeteer
Fri Mar 28, 2003 1:40 am
Forum: General Discussion
Topic: Simulated Candle Flame
Replies: 5
Views: 1038

Re: Simulated Candle Flame

I bought a Hallmark Christmas ornament a few years ago, something about the "Bearenstein Bears". It had a nice fireplace, with living-room-floor and mantle etc. (you had to buy the bears extra). But their FIRE! Ugh! They thought a FIRE could be simulated with a fast-flashing red LED! Their fire was ...
by gadgeteer
Fri Mar 28, 2003 1:03 am
Forum: General Discussion
Topic: Electronic Supplier
Replies: 5
Views: 1143

Re: Electronic Supplier

www.mpja.com www.goldmine-elect.com www.sciplus.com <p>Do an internet search on "surplus electronics"...<p>PS: sciplus has gadgets, toys, hardware; I bought everyone an "electric flyswatter", $10, for Christmas once. Knocks flies silly *they smoke and die if they stay on the grid for a few seconds)...
by gadgeteer
Wed Mar 26, 2003 11:06 am
Forum: General Discussion
Topic: led flasher
Replies: 14
Views: 2407

Re: led flasher

lm3909 makes an excellent flasher. It will flash a super-bright LED from an alkaline "D" cell for 3 years. Excellent car alarm simulator.<p>NS applications handbook has dozens of 3909 circuits, from alarms to dual-color-flashers to a radio.<p>I'm not sure how you're gonna control the speed, but plac...
by gadgeteer
Wed Mar 26, 2003 2:34 am
Forum: General Discussion
Topic: Timer off
Replies: 2
Views: 753

Re: Timer off

4038/4538 is a dual timer; it is edge triggered, so it should work for you (make certain the other trigger is tied toits idle rail...). HOWEVER---you can tie pin 2 of 555 high with a 100k, and trigger through a .01µF cap--should work fine...<p>(a 555 of course triggers on LOW...)
by gadgeteer
Wed Mar 26, 2003 2:02 am
Forum: General Discussion
Topic: Schematic
Replies: 15
Views: 2401

Re: Schematic

I wouldn't go much over-voltage-ratinged with an electrolytic; they have a bad habit of changing values if you severely under-drive them.<p>Drive a 20µF 110V at 6 volts, you may find it has changed to 5µF after a while...
by gadgeteer
Wed Mar 26, 2003 1:48 am
Forum: General Discussion
Topic: Looking For Cheap Crossover w/o any coils
Replies: 25
Views: 3663

Re: Looking For Cheap Crossover w/o any coils

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by mikea1962375: OK, I am lost. If th coil is 0.000212 henries, how much will the diameter, turns and wire length be? Does anybody know? Also, what gauge wire muct I use? Or what would be the best? <h...
by gadgeteer
Sat Mar 22, 2003 11:44 pm
Forum: General Discussion
Topic: Looking For Cheap Crossover w/o any coils
Replies: 25
Views: 3663

Re: Looking For Cheap Crossover w/o any coils

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by mikea1962375: First, what does the comma mean between 0,43 in one of your equasions. Also, how do I solve it? there are four variables, and I only know two of them. Thanks <hr></blockquote><p> You ...
by gadgeteer
Tue Mar 18, 2003 11:14 am
Forum: General Discussion
Topic: Looking For Cheap Crossover w/o any coils
Replies: 25
Views: 3663

Re: Looking For Cheap Crossover w/o any coils

BTW, the symbol "^2" is generally SQUARED. So: L=(D*N^2)/(l/D+0,43) (l/d + 0.43)(L) = (D)(N^2) (l/d + 0.43)(L/D) = N^2<p>Thus N is the quare root of the quantity [(l/d = 0.43)(L/D)]<p>You might start off GUESSING "l" at an inch, and see if you can wind it tighter; then recalculate with the REAL valu...
by gadgeteer
Tue Mar 18, 2003 11:05 am
Forum: General Discussion
Topic: Looking For Cheap Crossover w/o any coils
Replies: 25
Views: 3663

Re: Looking For Cheap Crossover w/o any coils

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by mikea1962375: I'm confused with what you told me. I have never made a coil before, except for small 5-turn ones that said in the book to do 5-turns. If I wanted a crossover for a sub, which I do, I...
by gadgeteer
Mon Mar 17, 2003 11:28 pm
Forum: General Discussion
Topic: Microphone to Amplifier to Speaker
Replies: 6
Views: 1436

Re: Microphone to Amplifier to Speaker

Buy an LM386 amplifier chip. $2 from Radio Shack, <$1 elsewhere. Works from 4 volts to about 15 (6 or 9 is ideal). Very simple---no extra parts (except for the 200µF speaker capacitor), it has a gain of 20. Add one more capacitor, it has a gain of 200. An additional capacitor + resistor for bias, on...
by gadgeteer
Mon Mar 17, 2003 11:12 pm
Forum: General Discussion
Topic: Looking For Cheap Crossover w/o any coils
Replies: 25
Views: 3663

Re: Looking For Cheap Crossover w/o any coils

What's wrong with making an air-cored-coil? Just a few turns will do it, and it's easy to wind one. You can use a bobbin, or a simple cardboard tube. A bottle of nail polish and a couple of bread ties will finish it up just right...<p>You can probably use the "X(l) = 2 · ¶ · f · L", ...