I need a timer that will actuate the "Lock" button on a car fob every half hour.
I can build anyting someone designs, I just can't design. Don't have the head for it.
I can probably get an aftermarket fob for my car. That much I know.

Kerry,

 

A 555 timer is problematic for a half hour delay.
Better to use a CD4016 in a timer circuit such as this.
Depending how what's required to actuate the fob, you may be able to eliminate the relay and just use the transistor to directly trigger the fob.

 

Okay more importantly why?

Dare I ask what is causing the need to have the door locks cycle every half hour?

 

I think it would be easier to hack into the car's wiring and place the timer there. A much larger battery will power the timer and the car will lock itself every half hour, as requested. In my car, this is accomplished with a grounding function. In other cars, it might require the application of a power pulse.

 

Since you will need to be within fob range of the car anyway, can't you visually/manually check the locks?

 

There are versions of the CD4060 that will run on a 3.6 V lithium coin cell. Selecting the oscillator components for 18.2 Hz will result in Q14 going high after 30 minutes. Post #10 in this thread:

http://forum.allaboutcircuits.com/t...ond-pulse-output-diagram.126929/#post-1034352

makes a 2 second output pulse after a 30 second delay. With some adjustments it can make the timings you want.

ak

 

Since you will need to be within fob range of the car anyway, can't you visually/manually check the locks?

Maybe he has OCD but is real lazy too so he wants to automate his OCD habits?

 

found another 555 http://www.customsiliconsolutions.com/products-for-ASIC-solutions/standard-IC-products.aspx
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NE555 is a TTL compatible "relict" i don't quite get why it is so popular for applications that do not require high power - high power is required for high slew rates for digital logic - high slew rates are required for digital logic to enable high resolution event -diferentiabilty/-density/-timing
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this thing can be run with nano-amps on random mono stable re-trigerable from few components - that activate higher power

((i can't believe me putting that farce up here))
the privilege of using Spice is it lets you do all sort of insanities . . . i must go to sleep

 

NE555 is a TTL compatible "relict"

No, it isn't. In 2005, over 1 *billion* were sold worldwide. And, it's spelled relic. And, that's not the right word for insulting an old thing.

high power is required for high slew rates for digital logic

No, it isn't.

this thing can be run with nano-amps on random mono stable re-trigerable from few components

No, it can't.
The circuit does not work
If it did work, no one in their right mind would build one.
If it were built, it would be outrageously expensive.

ak

 

No, it isn't.

yes, it is and it is to trivial for you not to know that , and it's not in a scope of this thread (simply put - if it is not then you should be able to dramatically reduce the power consumption of x74yZZ families - what is your excuse not doing that?)

you likely also late awake ... i was not telling that 555 can be run from nA - although i never tested so i don't know - i was providing "illustrative example of" ultra low frequency oscillator - and how to make it consume as little as possible . . .

. . . by setting absurd values for resistors for bi-polar op Amp you can put this macro model into operation even more low power draw than 200nA - but i'm sure this LT6000 oscillator will work starting from somewhere 1 ... 10 µA if not lower

 

Your post says "nano-amps" in the section with your schematic, so I did not apply that to any version of the 555. In that section is a schematic with an LT6001. The LTC webpage for that device has this title:

LT6001 - Dual 1.8V, 13uA Precision Rail-to-Rail Op Amp

From that I stated that the circuit in the schematic cannot run on nanoamps.

While within any particular semiconductor technology family it is common that more speed requires more power, applying that as a blanket statement to all digital electronics components simply is not true. In the mid 90's, a (single-chip) DEC Alpha processor dissipated approx. 50 W. Today a mobile Celeron has 10 times the computational horsepower and data bandwidth, and dissipates less than 5 W.

AND - Do you really think that presenting an example, with 50- and 100-megohm resistors, that is completely unbuildable is of any actual help to the TS, who admitted his lack of experience in his first post?

ak

 

i really don't think i should convince someone to definitely change it's beliefs
the 555 is in most cases easy to set up stuff -- if you want to use it go ahead
? does your celeron run on bipolar transistors like 555 (we have a different technology in question)

AND - Do you really think that presenting an example, with 50- and 100-megohm resistors, that is completely unbuildable is of any actual help to the TS, who admitted his lack of experience in his first post?

I want a 555 timer combined with a car fob:

I need a timer that will actuate the "Lock" button on a car fob

as far as i see those things run from 1 or 2 3V Li cell buttons - if you put the 555 inside there - you just as well can short circuit those batteries
you have to run any extras there as low as possible even the 200 nA time-average would be perhaps too much (i just put up a very poor example to right direction - specially denoting - it being a farce - since we didn't had anything better here ?)

and i don't think it's 100% impossible nor unreasonably expensive - if you can find the right people nearest to you - to make extension PCB - to solder the components - to attach the extention (http://hackaday.com/2014/01/05/testing-the-limits-of-home-pcb-etching/)

 

? silence ...

A 555 timer is problematic for a half hour delay.

i'm really not to test every blody ciruit in real - but it (modified src.) does simulate (i didn't build this dummy simulator - so redirect your problems right - next time . . .)

Better to use a CD4016 in a timer circuit such as this.

- indeed!

although there are this it must be considered that any extras to key-fob may alter the transmition frequency (as although the added hw emulates a button press then due to altered fq. the receiver in car misses the evt.) -- those guys have a different opinion

___________________________________________

so options

1. perhaps the manufacturer of your car security system can program it's device including your desired function
   sum: you receive the new fob according to agreed price (or they actually have to pay you as an idea source of a useful feature - that the other people find useful)
   
2. perhaps there're avail the security system that already has the feature desired implemented
   sum: you pay the installation of the new system
3. perhaps the desired function is applicable by intercepting your car side security module
   sum: it's possible to use whatever you can come up with eighter feed from car battery or special backup one ...

for AnalogKid - everything so F-n complicated so my D falls off starts growing as a 3 before we get it done (Damn!) . . . as far as such dummy disputes provide educational effect for starters in electronic engineering - i don't care - if it's just for seeming/virtual position battle i find it impurposed . . . every one knows their own thing best and the things by features that suit best for their line - it's like nothing to dispute here? ← about this i'm full of receiving "the Windows don't work" , "The viasat hanged" , etc. to may neck at every other day at home - so you are just the last tiny link at the end of this + you have enough time to dispute me but you have no time to advance the thread - so i have to be the responsible idiot doing this - because everyone else F their duties . . . sooo enlighting!!!

 

about what everything can go wrong while attempting to modify your key fob

1. break the case on open
2. some models loose their programming when battery is disconnected
3. damage the board (PCB) eigther by a mechanical force or heat
4. damage the components by ESD
5. damage the components by wrong heat/duration it is applied to
6. unkwown

so these guys actually were very lucky/or experienced in the video - that's also why i said "finding the right people"

 

Kinda getting the impression you're all engineering for nothing. I'm guessing the OP's a one post wonder and done flew away never to return.

 

. . . . . . . . . . . . . . . who drank my milk

 

Kinda getting the impression you're all engineering for nothing. I'm guessing the OP's a one post wonder and done flew away never to return.

Sorry all. I have been very busy and don't get on line much.
Long and short of it. My Key fob is too easy to pocket-trigger. Sometimes, on rare occasions, I actually forget to lock it.
I have woke up to a car that is unlocked at times when I was positive that it was locked before going in the house.
There are people in my neighborhood who ransack unlocked cars. three times I have had to put everything in the glove box, etc. Nothing stolen but, it's a pain to have to go through.

I was looking for a technical solution to a behavioral issue.

Maybe I would be better off to turn my car into a honey pot. Put a GPS tracker in an old laptop...

 

I was looking for a technical solution to a behavioral issue.

You still haven't said anything that would make my post #4 a bad idea.