I asked the same thing, 555 doesn't work for times that longer
Camera intervalometer
12hour timer using two 555 timers.
- 20th February 2009 03:29 AM #1dottedquad
12hour timer using two 555 timers.
Hello all, I'm currently working on a project that utilizes two 555 timers. The first 555 timer controls the 12 hour(I'm assuming the delay) once the 12hour has been met, trigger the second 555 timer to turn on a relay for approximately 2-3 seconds. Once the 2-3 second is met trigger the first 555 timer. That sounds simple so far except when I run into the RC circuit. I'm not sure what resister and capacitor to use for the 12hour.
I realize I can use a kitchen timer to set the on and off times and hook that up to the 2-3 second 555 timer. I'd rather not use this approach.
-Thanks,
rich
- 20th February 2009 03:31 AM #2Menticol 0Felipe
Visit my blog cocodrilabs.wordpress.com - Electronic Projects, DIY Repairs, Device Modification and Improvement.
- 20th February 2009 03:37 AM #3dottedquad Wonderful! I apologize for double posting. I did a search for 12hour 555 timer which yielded no results. As I wasn't sure what else to search for, I posted my question.
Originally Posted by Menticol 
-Thanks0
- 20th February 2009 05:25 AM #4creakndale
You might try to locate these Exar Long Range Timer IC's on eBay for your 12 hour delay:
XR-2240
XR-2242
creakndale0
- 20th February 2009 06:42 AM #5davidbear
Are you fundamentally opposed to using another chip other than the 555? I'm no expert, but I would think that you could set the first 555 to run as a multivibrator at say 0.1Hz, feed that signal into a 14-bit binary counter, and have it set off your second 555 to release a 2-3 second burst and reset the 14-bit counter.
0Last edited by davidbear; 20th February 2009 at 06:44 AM.
- 20th February 2009 01:56 PM #6KMoffett
Maybe something like this?
Repeating Interval Timer
Ken0Last edited by KMoffett; 20th February 2009 at 01:57 PM.
"To invent, you need a good imagination and a pile of junk."
Thomas A. Edison (1847 - 1931)
- 20th February 2009 07:13 PM #7dottedquad I'm a beginner at electronics. I'm afraid that's way over my head. I'm not quite sure how that would work. Also, I'm not opposed to using another chip other than the 555. I was checking out the CMOS 4060. Originally Posted by davidbear
-rich0
- 20th February 2009 07:41 PM #8blueroomelectronics Help us help you
The 4060 will require lots of dividers to get 12Hrs. Is it going to be connected to AC (Mains)? If so you could drive the counter with a 50/60Hz signal.
0
- 22nd February 2009 01:17 PM #9Hero999
Don't expect great accuracy.
Two Simple 24-Hour Timer Circuit Schematics0
- 22nd February 2009 01:23 PM #10notauser
Another option would be to see if you can find a dollar store digital clock or something you can rip apart and tap into..
0
| Tags |
| Similar Threads | ||||
| Thread | Starter | Forum | Replies | Last Post |
| 555 timers | ch.v.v.kumar | Electronic Projects Design/Ideas/Reviews | 6 | 4th July 2011, 08:02 AM |
| i need tow timers,but AVR simulation "avrsim version1.11" have one timer | kasser | AVR | 5 | 25th February 2007, 09:22 AM |
| Do u have 12hour PIC16F84A clock | pasanlaksiri | Microcontrollers | 2 | 8th February 2007, 09:14 PM |
| 555 timers | jasona@wbeer | Electronic Projects Design/Ideas/Reviews | 4 | 31st August 2005, 08:37 PM |
| Timers ? | Titanium | General Electronics Chat | 5 | 30th July 2003, 10:26 AM |