rg@sisd.kodak.com (Rich Gortatowsky) (09/30/90)
Hi all... I'm no whiz at electronics, so's I need some assistance.
I am a auto modeler and wish to add blinking lights (ie: turn signals)
to a model. I have the LED's all set and working for running lights etc.
How... preytel... does one make a "flasher". I'm basically using only
2 volts er so imput current. I assume there is a simple (cheap?) way?
Does it require a relay? If so... well... A simple? diagram of such a
circuit would be most appreciated!
THanks!
--
Jeff Gortatowsky {seismo,allegra}!rochester!kodak!elmgate!jdg
Eastman Kodak Company
These comments are mine alone and not Eastman Kodak's. How's that for a
simple and complete disclaimer? lamb@brahms.udel.edu (Richard E Lamb) (10/01/90)
Best recommendation is to use an LM 3909 LED flasher chip. It's a little 8 pin guy and works great. Best of all, you can get one at the Radio Snack for a buck, and one of the RS "HOW TO" books shows how to hook it up.
gz@pta.oz.au (Electric Blue) (10/02/90)
In article <1990Sep30.043045.22757@sisd.kodak.com>, rg@sisd.kodak.com (Rich Gortatowsky) writes: > > I am a auto modeler and wish to add blinking lights (ie: turn signals) > to a model. I have the LED's all set and working for running lights etc. > How... preytel... does one make a "flasher". I'm basically using only Just use a flashing led. They look just like a normal led and are available for under $1. Looking at the Radio Spares catalogue they are available in red, green or dual colour. Just connect power and flash away. > 2 volts er so imput current. I assume there is a simple (cheap?) way? > Does it require a relay? If so... well... A simple? diagram of such a > circuit would be most appreciated! If you really want to build your own cct you can use an LM3909N led flasher ic made by National Semiconductors. These retail for about $1.50 and run on 1.5 to 3V. the cct is as follows: +------------------+ | ________ | LED +-----|1 8|-----+---|<---+ +-||--|2 7| | C1 |3 6|--------------+ +---|4 5|---+ | -------- | | | | V- V+ | +--- ---+ C1 is 300 uf for a flash rate of 1HZ. To have a faster rate simply decrease the value of C1. LED can be any normal led. The cct uses the voltage across the timing capacitor C1 as a boost voltage so it can flash green leds from a supply voltage of as low as 1.5V. > > THanks! > Hope the above helps. > > -- Login name: gz In real life: George Zisis +61 2 415 0515 (RTC, CSC, RTOC, or any other acronym you care to think of..) -m---------- Pyramid Technology Australia ----mmm-------- -------mmmmmm----- ----------mmmmmmmmm--
cgordon@vpnet.chi.il.us (Gordon Hlavenka) (10/03/90)
>... I have the LED's all set and working for running lights etc. >How... preytel... does one make a "flasher". I'm basically using only >2 volts er so imput current. I assume there is a simple (cheap?) way? > Best recommendation is to use an LM 3909 LED flasher chip. If you're going to the Shack, you might as well just buy flashing LEDs. They come in Green (PN 276-030) or Red (PN 276-036) and the catalog lists them at $1.29 each. You can't get much simpler (electrically) than 2 wires. From the modelling perspective, if you built the whole thing around the LEDs you might be better off with a flasher chip. Another advantage of this is the fact that all your flashers would be synchronized. Personally, I'm partial to the 555; take your pick. (Personal philosophy note-- The 555 and 324 are the peanut butter and ketchup of electronics: If you have enough of them you can build anything.) ----------------------------------------------------- Gordon S. Hlavenka cgordon@vpnet.chi.il.us Disclaimer: Yeah, I said it. So what?
lamb@brahms.udel.edu (Richard E Lamb) (10/06/90)
I'd still go with the LM3909. It does wonderful things to battery life. I used to build display model aircraft. The first was a B52 (yep, da BUFF) that used 555's to run the strobes. A 9v battery lasted about 2 hours. The last one was a large Tomcat - with 2 seperate beacons, INCANDESCENT strobes (they look GREAT!), cockpit lighting - the works. Two D cells in the tailpipes lasted over a year (using LM3909's and CMOS logic chips). One idea (not yet implemented) was to make _WORKING_ _SCALE_ radar display screens! Can anybody guess how? Richard