I'd like to make a series of LEDs flash, then go on steady; I'd also like to use 555(s) to do it, because I think it'd be fun.
This is nothing more than trying to figure things out, but since I'm most familiar with auto and aircraft systems, I've been using 12V to power this:
http://downloads.deusm.com/designnews/352-gadget102504.pdf. I also have a 12V wallwart that works easily with my breadboards, so that plays into the situation as well.
I learned that what I want is called a "Brake flasher," or some variation of that, even though it's not going into a vehicle.
I've tried several of the circuits that I came up with in Google, and the above linked one is the only one I was able to make work...but the ONLY way I was able to make it work was by removing the jumper from U2, pin 8 to +12v.
I played around with C3 and C2 to get a series of flashes that I liked with just a single LED and resistor off of U2, pin 3.
But that's where I ran into a wall.
I figured that if I could get a single LED to blink then be stable on at the press of a button (listed as "Vehicle brake pedal switch," in the link) that it would be a matter of sliding a transistor in place of the LED I had from U2, pin 3 to +12, to drive a larger LED lamp array. When I put anything but an LED/resistor on U2, pin 3, however, all I get is a steady on at button press.
I don't have the exact item called out for in the link for Q2 (called out is "IRF5210"...seems to be a P-chan FET, but an N-channel seems like it should be what's there...) but I've tried a 2222 (NPN), 30N06L(N-chan) and an IRF4905 (P-chan) and the best I can get is for the LED to turn on dim for a few seconds, then bright as long as the button is held.
I don't have an O-scope, so I can't tell what's really going on at U2, pin 3, but my DMM reads 9-ish volts out there after the button is pressed and held, and if I have an LED hooked up between there and +12V, I get a very pleasing flash, then steady at every button press.
It really seems like at that voltage output on U2, pin 3, I should be able to put almost anything on pin 3 to control ... FET, relay or whatever. I still get nothing more than an on/off with anything other than an LED-resistor load.
All that being said, can someone point me in the right direction to drive a higher current load, have it flash then steady on at a button press, and maybe even break it down Barney style why your solution is good and mine failed?