zgeniez Posted September 20, 2005 Report Share Posted September 20, 2005 Regarding the LED Pulser:http://www.electronics-lab.com/projects/motor_light/020/ C1 is a 1µF 63V Polyester Capacitor. Can someone tell me what makes this cap significant in terms of the material (polyester), and voltage? Does it need to be polyester? Why such a high voltage, can that vary significantly? Thanks! zac Quote Link to comment Share on other sites More sharing options...
Staigen Posted September 20, 2005 Report Share Posted September 20, 2005 Hi there zgeniez, velcome to this boardAny lowleakage , nonpolarized cap will work here! ;DThe voltage rating should be at least the supply voltage for safety! ;D ;DWhy such a high voltageHigher voltage usally means lower leakage(at low voltage)(not always)//Staigen Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 20, 2005 Report Share Posted September 20, 2005 I made LED fading projects something like this one.I use red, green and blue ultra-brite LEDs, each with their own fading circuit and each circuit has a slightly different rate. When shining on a white ceiling they combine to make all colours of a rainbow with the colours and their brightness continuously changing slowly.Instead of driving the LEDs with a voltage ramp through a current-limiting resistor, my circuits sense each LED's current and drive it with a ramping current for better brightness control at very low currents.Instead of a linear ramp, my circuits use a logarithmic ramp for a very wide smooth brightness range.I'll post it as a project after I reverse engineer one (I lost my schematic).Now Wal-Mart has a cheap Chinese one. It makes the ramps digitally, with about 32 obvious jerky steps of brightness for its LEDs. It even has many patterns to select, or you can let it sequence through all its patterns. I keep its volume very low because I don't like its sound of birds and surf. ;D Quote Link to comment Share on other sites More sharing options...
zgeniez Posted September 20, 2005 Author Report Share Posted September 20, 2005 Awsome thank you very much! So, I'm assuming a polyester cap is the same thing as a mylar? The polyester is just the insulator correct? Another question...is it possible to modify this circuit so the fade time will vary randomly? With the addition of a couple more caps, or would you need to add something more like a 555 timer circuit? Thanks again! Quote Link to comment Share on other sites More sharing options...
Staigen Posted September 20, 2005 Report Share Posted September 20, 2005 Hi there zgeniezThe polyester is just the insulator correct?Correct, but i dont think it is same as mylar!Another questionWait for Audiogurus project, to find out how he have done it!//Staigen Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 21, 2005 Report Share Posted September 21, 2005 I use 1uF polyester caps in other projects. In my LED fader project I used a cheap electrolytic since it is charged and discharged with a single polarity.It would be very difficult to make a fader so the fade time varies randomly. Quote Link to comment Share on other sites More sharing options...
zgeniez Posted September 22, 2005 Author Report Share Posted September 22, 2005 Hey thanks to both of you. Time to start soldering! I'll keep checking back to see this new, old circuit. I am actually a glass worker who has always had a facination with electronics. I've wanted to make some magic aquarium creatures...things that glow and pulsate. It's taken a couple years to learn the skills for the glass. Now it's time to work on the magic....breathe life into the little zombies! On this same path of pulsating light, and looking down the road a bit...how do you think this circuit would convert over to smt? I like the low part count, i just know i am going to want an even smaller package and less power in the long run. Any thoughts? ~Zac~ Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 22, 2005 Report Share Posted September 22, 2005 Hi Zac,I tried to sell my blinking projects at my city's "midnight street party" for 20 bucks.There were Chinese people there selling by the thousands brightly blinking buttons similar to my big ones for only 2 bucks! They used surface mount parts and a main microcontroller IC. Their small button battery cells won't last long. Replacement cells cost much more than their whole product!They had bouncing translucent balls with blinking LEDs inside. They had a gadjet that spun around a display of multi-coloured LEDs in changing patterns, very cheap.I bought some solar-charged garden lights on sale. They have real glass spheres (not plastic) with the surface of the glass shattered in many lines. Inside is an RGB ultra-bright LED that slowly fades the brightness from one colour to the next. They have a microcontroller making them work, and old-fashioned Ni-Cads as their battery.They are so bright that they shine on the ceiling of my bedroom, off-axis and pretty far away. If the sun charges them all day, they work all night long. When it is cloudy, they work only an hour.If you are good at drilling holes in glass to mount LEDs (I had a hard time drilling CDs) then you could make some of my "6V Ultra-bright LED Chaser" projects http://www.electronics-lab.com/projects/games/004/index.html Quote Link to comment Share on other sites More sharing options...
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