Happy birth year, 555

The 555 was launched in 1972 and turns 50 this year.


We need to know when it's half birthday of it's 55 year comes round. Then it will be 55.5


I've always wanted to do something with 555 but I can't think of an instance that a microcontroller wouldn't be better in every way.

They are great for making even squarewaves at variable frequencies. I use them for this purpose to generate better musical notes than armtel chips can.

I have a friend with an RV that is parked most of the time. Mice have chewed on the wiring in the engine bay. I used a 555 and 3 bright white LEDs to make a unit in a 3D printed case that flashes the LEDs for 50ms every 3 seconds. It is powered by the RV battery. Since he put one in the engine bay of his RV he has not had any more trouble with the mice eating the wiring. I have made several for other people and they say that it works.

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@er_name_not_found Chiptunes are pretty great. Unless they aren't.

@groundFungus Maybe your friend should quit dropping sandwich crumbs in his RV. :wink:

Yep, or maybe Chrysler should not make their wiring insulation so tasty?


Maybe they're just doing it out of spite. Dunno why, it's not like we've been mass-murdering them for hundreds of years or anything.

EDIT - In all seriousness, the 555 is pretty useful, but being a microcontroller guy I can't see myself using one by itself.

How are they better? They are still square waves, aren't they?

Got a 'scope?

A microcontroller costs more and requires software.

I'm checking now to see if an ATTiny84 costs more than an NE555.

The software isn't a big deal. It's easier for an idiot like me who's not in college yet and so hasn't taken an EE course.

EDIT - The Tiny costs more. Better for prototyping (if you're not an EE) but worse for production then.

Weirdly I don't own any NE555s. Or Tinys for that matter.

I was using the triple nickel chips long before microcontrollers. There are so many uses for them that there are books written just about using them.

Is there any other chip that is in production that long? 7400 is almost obsolete..
@555: congrats!!!

Arduino makes mostly rectangular waves.

My 555 big project was to use a 556 wired up as a sweep frequency generator firing a gunn diode. I had a current change detector on my radar detector. When the radar detector began to draw current from a radar detection, the gunn diode would be triggered and I'd just go zipping on by in my car.


my first attempt at electronics, a capacitive discharge ingnition unit basied on a 555, was in 1975. I learned all about 'magic smoke' :frowning:

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I built an intermittent wiper delay with one.  That's three automotive applications right there!   :smiley:

I make turn signal flashers with them. So you don't need those big low value resistors to convert to LED's in old muscle car's. They fit right in the original cans. That makes it 4 now. You wouldn't believe how much they charge for those if you want to buy one

You mean it's difficult to get exactly 50% duty cycle? Or are you just pulling my leg?