Author Topic: EEVblog#160 – 555 Timer Easter Egg?  (Read 14906 times)

0 Members and 1 Guest are viewing this topic.

Offline metalphreak

  • Frequent Contributor
  • **
  • Posts: 815
  • Country: au
  • http://d.av.id.au
    • D.av.id.AU
EEVblog#160 – 555 Timer Easter Egg?
« on: April 02, 2011, 01:25:06 am »
Hey Dave,

Can confirm the same thing happens with a SGS THOMSON SOIC package 555!

Easter Eggs in everything. It's crazy.

Offline dimlow

  • Frequent Contributor
  • **
  • Posts: 301
  • Country: gb
  • Likes to be thought of as
    • Dimlow Ponders
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #1 on: April 02, 2011, 02:37:35 am »
Hey Dave,

Can confirm the same thing happens with a SGS THOMSON SOIC package 555!

Easter Eggs in everything. It's crazy.

Yep confirmed it TODAY!
 

Offline firewalker

  • Super Contributor
  • ***
  • Posts: 2306
  • Country: gr
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #2 on: April 02, 2011, 02:48:30 am »
I love Easter Eggs (on every date :p). In one of my projects containing an alphanumeretic lcd the "Easter Egg" was instructions for obtaining the source code.
Become a realist, stay a dreamer.

 

Online Hero999

  • Super Contributor
  • ***
  • Posts: 11290
  • Country: gb
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #3 on: April 02, 2011, 05:30:24 am »
Interesting.

Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.
 

Offline oPossum

  • Frequent Contributor
  • **
  • Posts: 487
  • Country: us
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #4 on: April 02, 2011, 06:31:46 am »
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
 

Online Hero999

  • Super Contributor
  • ***
  • Posts: 11290
  • Country: gb
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #5 on: April 02, 2011, 06:33:55 am »
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
Lol, you can't be serious. Perhaps Dave should test this?
 

Offline buffalo960

  • Contributor
  • Posts: 22
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #6 on: April 02, 2011, 06:44:58 am »
I think I should show this video to my digital circuits class today ;)
 

Offline Strube09

  • Regular Contributor
  • *
  • Posts: 125
    • Blog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #7 on: April 02, 2011, 06:57:07 am »
Yep,

But it doesn't seem very stable on my end.... Will have to test again tomorrow to see if it works again  ;)
 

Offline oPossum

  • Frequent Contributor
  • **
  • Posts: 487
  • Country: us
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #8 on: April 02, 2011, 07:29:15 am »
Lol, surely you can't be serious.

I am serious. And don't call me Shirley.
 

Offline Lance

  • Frequent Contributor
  • **
  • Posts: 312
  • Resistance if futile if R<1Ohm
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #9 on: April 02, 2011, 09:50:28 am »
Wow, this is pretty cool! I'll see if I can give it a try.
#include "main.h"
#include <pic.h>
//#include <killallhumans.h>
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 27204
  • Country: au
    • EEVblog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #10 on: April 02, 2011, 10:16:54 am »
Interesting.

Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.

Hans was a clever designer, I'm sure it's very subtle...

Dave.
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 27204
  • Country: au
    • EEVblog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #11 on: April 02, 2011, 10:18:48 am »
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.

Awesome, will have to try it.
Hans was bought back to design the 7555, so makes sense he put something in that too.

Dave.
 

Offline Lance

  • Frequent Contributor
  • **
  • Posts: 312
  • Resistance if futile if R<1Ohm
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #12 on: April 02, 2011, 02:51:08 pm »
I wonder what would happen if you made a 555 out of discrete components.
#include "main.h"
#include <pic.h>
//#include <killallhumans.h>
 

Offline steaky1212

  • Regular Contributor
  • *
  • Posts: 84
  • Country: gb
    • Steaky - Sleep is overrated
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #13 on: April 02, 2011, 06:45:23 pm »
Am I the only one that thinks April Fools??
 

Online Hero999

  • Super Contributor
  • ***
  • Posts: 11290
  • Country: gb
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #14 on: April 02, 2011, 07:13:33 pm »
Am I the only one that thinks April Fools??
Of course, lol, I can't believe we fell for it.
 

Offline tnt

  • Regular Contributor
  • *
  • Posts: 237
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #15 on: April 02, 2011, 07:30:13 pm »
A question would be "how did he do it ?".

I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?
 

Online Hero999

  • Super Contributor
  • ***
  • Posts: 11290
  • Country: gb
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #16 on: April 02, 2011, 08:25:30 pm »
What didn't make sense to me was the frequency seemed to be changing slightly, yet he detected the modulation using a simple low pass filter which shouldn't work, so it should've been obvious something was a miss.
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 27204
  • Country: au
    • EEVblog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #17 on: April 02, 2011, 08:43:47 pm »
I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?

I can assure you, the scope leads were connected directly to the 555 as explained.

Dave.
 

Online Hero999

  • Super Contributor
  • ***
  • Posts: 11290
  • Country: gb
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #18 on: April 02, 2011, 09:33:53 pm »
The circuit doesn't match the schematic.

The pot is really 200R rather than 500R and then there's all those resistors connected in parallel.

The pot should also never be allowed to go too low otherwise it'll burn out the discharge transistor in pin 7 so there should be a fixed resistor in series with it.
 

Offline neoone

  • Regular Contributor
  • *
  • Posts: 70
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #19 on: April 02, 2011, 11:04:19 pm »
I can assure you, the scope leads were connected directly to the 555 as explained.

Dave.
Is there a prize for figuring out how you did it? ;)
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 27204
  • Country: au
    • EEVblog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #20 on: April 02, 2011, 11:53:12 pm »
It matches.
As mentioned, the values are approximate.
Only found a 200R pot in my kit, so used a series resistor as well.
The 1k5 is made with 3 resistors to tweak the value so I could get the range needed.
No trickery in the resistors at all.

Dave.
 

Offline ShiftPlusOne

  • Regular Contributor
  • *
  • Posts: 51
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #21 on: April 03, 2011, 02:42:29 am »
I hope there's a reveal coming up then.
 

Offline neoone

  • Regular Contributor
  • *
  • Posts: 70
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #22 on: April 03, 2011, 04:32:56 am »
and that's a normal 555 timer not some uC in DIP8 ? ;) I don't suppose Dave did something with Agilent scope heh. 
 

Offline ShiftPlusOne

  • Regular Contributor
  • *
  • Posts: 51
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #23 on: April 03, 2011, 05:49:18 am »
Not just an engineer, but a magician also apparently.
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 27204
  • Country: au
    • EEVblog
Re: EEVblog#160 – 555 Timer Easter Egg?
« Reply #24 on: April 03, 2011, 07:55:41 am »
and that's a normal 555 timer not some uC in DIP8 ? ;) I don't suppose Dave did something with Agilent scope heh. 

Yep, brand new bog standard National 555 timer.
Try harder!

Bueller?, Bueller?

Dave.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf