NON 555 Cyle Timer

Is this for windshield wiper delay ? if so google that, " wiper delay circuit should get you drawings.

It would be helpful if the OP would clue us in on the intended application.

Or even respond lol. Maybe I am too impatient :))

Windshield wiper delay would never have NO/NC output. I need to trigger and input and have a NO/NC contact activate for between 0-9.9 seconds. Very similar to a car alarm that sounds a siren for 30 seconds when a motion detector sends a pulse.

this style comes in decons also

This timer could never provide provide 1/10th second accuracy.

Not sure if there's backside to this unit but I wouldn't be sure how to control to the 1/10th of a second with this. Ecspecially becasue it's geared for the 1 sec to 5 min rate. Anything over 10 seconds is overkill. Thanks though!

Yep. RS Components, Maplin Electronics and Tandy do (usual disclaimers), among others.

RS Components has almost everything. But trying to simply find a 0-10 second version of this that can do 100ms incraments is no small chore: http://www.aliexpress.com/item/Free-Shipping-1PC-12V-Home-Automation-Delay-Timer-Control-Switch-Module-Digital-display-LED/1317308022.html

Yes. This is probably the best plan. Thanks for this idea!

Are you awre that there is a CMOS version of same 555 but has a part number 7555.This has leakage currents of the order of nano amps and can be used to get longer times of the order of few 100 seconds etc easily. Internally - as well as external circuit is concerned it is like 555- but you can use mega ohms and micro farads to get longer times. There are many off teh shelf items- but if if you want to understand and build one your self- just use 7555

Crystal controlled PICs would achieve what you want after a relatively simple program has been written for it.

Even the PICAXE versions, running their own style of the BASIC language, should be able to do it very accurately with their even simpler programming language as well as being really cheap....

All needed software and manuals are free to download and use. No hardware Programmer neeeded, just a few resistors and a cheap COM or USB cable form a programming interface and an old PC or Laptop (new Laptops can of course also be used if available!!).

All infos needed are in the free manuals.....

See here:-

http://www.rev-ed.co.uk/

The really good point is that if a need is found to change the way the program runs, this can be easily and quickly reprogrammed, "in situ" if required, to achieve the new requirements......

We have 30 or so of these units in our shop:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190938375297&ssPageName=ADME:X:RTQ:US:1123

Problem is they can't do 0.1 seconds past 1 second. They do 0-999ms. We need 1.6, 2.3, etc...

Someone else mentioned changing the cap on an off-shelf 555 unit. Perhaps changing the resistor value and upgrading the cap may do it. If a 555 based circuit is set up for 0-9999ms, that might do the trick.

A very simple one,

Not sure where you're located, but if you're in US, your local Radio Shack would have the Pic or Arduino Uno or Arduino Micro which will take longer to get out of the package than it will to program for this function. The micro is a 40 pin size version. The accuracy is many times better than any 555 device and it has outputs that can be programmed high or low or as inputs high or low or analog inputs that can sense the pot wiper when the ends are tied to gnd and 5v, 1028 positions. Or you can program it to a led 7 seg display to see the set time. You'd spend more time soldering around the 555.

Very well and accurately put!!

But will he believe you (us!)....

Its the only modern way to go.

I paid far more for 555 chips (in comparison!) 40 years ago than the bottom end PICAXE (good enough for the job!) chips do today....and a PICAXE is FAR more fun and far more flexible.....

Though I have to say that I still vote the (43 year old!) 555 as the best chip of all time, but the PICAXE family are creeping up VERY fast!!!!

I do not know personally of an older chip than the 555 that is still produced in the numbers of the 555, but if you know better, please let us all know here, thanks.

The 555 was introduced in 1971 first by Signetics! Though changes and improvements were made by several other companies over the years. As of 2003, it was estimated that 1 billion units are manufactured every year.

For those interested, at least the following manufacturer made them, even the east Germans made copies:-

Way tooooo much building! But thanks! :)

Actually, the building of a 555 unit is just about the same as building a PICAXE circuit.....but with higher possibility that you will need to re-design/improve with a soldering iron. The possibility that the initial version works first time 100% correctly is very small.....of ANY unit using any technology.

Also, an Arduino/PICAXE unit can be bought built, so basically, only the program needs writing....a few lines should do it.

The Arduino/PICAXE is also easily re-programmed/Tuned, without a soldering iron!!

But the decision is entirely yours, our job is just to tell you "how it is"....

One way is to use a smaller, higher quality capacitor in a 555 circuit running at a higher rate followed by a counter.

http://www.reuk.co.uk/Timer-Circuits-With-4060B.htm

Thanks Rixter. I'm heading in this direction. Great reply.

Anyone know of a reasonable source to build a prototype? Even a unit like this modified to control 0-999ms, further taking out the push button controls and replacing with a potentiometer where all the user would see is a large readout and knob to increase and decrease time intervals. The timing in this project changes frequently. The key to the finished result is "simplicity".

If it has push buttons now, it is highly unlikely to accept a pot instead without major changes to the circuit. The other way round too......

You might be able to interface a digital rotary switch encoder in place of the buttons.....just a thought!

Or just accept the buttons.......no biggy!

A thumbwheel switch will give you better setting accuracy. Make a crystal controlled oscillator and divide to 1mS and use presettable counters.

Gajanan Phadte

We found a manufacturer in China to do just that. Small design fee, accurate to 10ms - 100pc order. Well worth it.

GreenTeaGuy:


I do have one such precision timer which has 10ms to 100ms precision re-trigger SPDT output possibility.

Give me details on your external trigger input source pulse width, voltage, noise and variations in it and having chances of trigger again while output is active.

We have X10ms interval timer generated from 12MHz clock 100ppm/C and we read time width from push wheel switch 0 to 9 range in which time is used as 10ms to 100ms where 0 is used as 100.

We can also set it as X100ms time intervals and with two switches displaying 00 to 99 you can have timer of 0.1s to 10s.

Write to me if you need help.