Need help with counting pulses to timer

[jr2233]

I have a single push button switch S1 (like a doorbell), I would like to press S1 one time and after 30 minutes an LED will turn on then off (high then low). I do this now with a one-shot timer circuit using a 4093 or a 555 timer. I would like to be able to press S1 2 times and the delay to the LED would be 60 minutes. Or press S1 3 times (in a row) and the delay to LED would be 90 minutes, etc... The output (LED) would go high just momentarily. I need help on how to do this with minimum of parts, the 30 minute time period does not have to be precise, I can use a single R/C. I am clueless on how to store or latch the counts and then add them to the timer, I heard a 4017 could do it but I am not sure on how do to it. I only have a single S1 as an input and a single LED as an output. hope someone has an idea, thanks...jr

 

[MikeMl]

How long should the LED be lit? Are you any good with PIC programing?

 

[jr2233]

thank you mike for responding. I don't have much pic knowledge but a pic would be too expensive for this app. The LED only needs to remain on for under a second, enough to turn on an SCR (an LED is not realy used). I think I need to do this with a 4017 or similar IC costing 20 cents. I believe a 3 or 4 step sequencer circuit that switches from one output to another depending on how many times S1 is pressed would be the right direction. I just don't know how to do this since I never built or needed to build such... thanks...JR

 

[MikeMl]

I'll bet that a dirt-simple 8 pin Pic like this one will be the most cost effective. By the time you de-bounce the switch, find a capacitor that has sufficiently low leakage to make a 90min timer, wire up a dozen other parts, how can you compete?

 

[Pommie]

Yes, it's pretty difficult to beat a 50c pic.

Mike.

 

[Mike - K8LH]

I agree too guys. The 10F200 in an 8-pin DIP package is only 55 cents at Mouser; PIC10F200-I/P Microchip Technology Microcontrollers (MCU)

If this is a "one off" application I'm sure someone on the Forum could help by writing the program in about 30 minutes. If you add location info' to your profile someone in your area might consider burning the program into the PIC for you. If this is a commercial application then you might consider paying for the code or offering royalties.

Regards, Mike

 

[jr2233]

Thank you for your info. This excites me, I never knew Pic's were so low priced. Years ago in Nuts and Volts I used to look at basic stamps. I will look at some data sheets today. I live in central Florida and would gladdly pay for someone's help. So with the PIC I would not need R/C to create timers? Perhaps some of the rest of my circuit consisting of a 4093 could be replaced with the same single PIC? ....JR

 

[Pommie]

Depending on what you are doing the pic might be the only logic component needed.

Mike.

 

[Mike - K8LH]

Thank you for your info. This excites me, I never knew Pic's were so low priced. Years ago in Nuts and Volts I used to look at basic stamps. I will look at some data sheets today. I live in central Florida and would gladdly pay for someone's help. So with the PIC I would not need R/C to create timers? Perhaps some of the rest of my circuit consisting of a 4093 could be replaced with the same single PIC? ....JR

You would not need R/C parts to create a timer. There's a built-in 4-MHz oscillator (1% accuracy) time base that you use to derive whatever frequencies you need. Depending on what you're doin' with the '4093 you can probably create the same logic in software in the PIC program.

Regards, Mike

 

[jr2233]

thanks for replying. I have thought all weekend about using a PIC to do this. A slight change to the requirements might make things easier I hope... A single push button input switch S1, A single output port that triggers a small SCR (R22-2) with a positive pulse. A 30 minute timer. If you press S1 one time, the Scr is triggered one time 30 minutes later. If you press S1 2 times in a row, the SCR is triggered one time 30 minutes later and again 30 minutes later after that (2 pulses one every 30 minutes apart. Press S1 3 times in a row and the SCR is triggered once every 30 minutes for 3 times. This setup would fit right into my existing circuit and work fine. I am located in central Florida and would gladly pay someone to program a PIC10F200 for me. Thanks again for your replies...JR

 

[Mike - K8LH]

I would be happy to help, with qualifiers. I can write and test or simulate the program relatively quickly but I'm on the road (currently near Allentown, PA) and won't be home to program that puppy for you until the weekend.

Mike

 

[Pommie]

I could and would help with the code but am going on vacation tomorrow. If your still stuck in a weeks time I'll chip in.

Edit, i see Mike offered. You won't get any better. (there are too many Mikes on this forum)

Mike.

 

[jr2233]

Ok, I can waituntil you are ready. The sooner the better, I have someone in California waiting to layout the board. Another part of the circuit has a 4093 (Quad 2-input NAND Schmitt Trigger, I am using it as 2 coundown timers) As much as I am itching to improve on that one as well with the same or second PIC, I would have difficulty describing its total function in the circuit. All I know is that it works perfectly as is. thanks again...jr florida

 

[jr2233]

Hi mike, are you serious about helping out this weekend? let me know I have also written a description of another part of the circuit that if you want can also be converted to Pic. ,waiting for your reply..jr from daytona beach florida. i need some one to program this for me, should I purchase a programmer, if so which one would you recommend...thanks again, mrtelephone@earthlink.net.....

You would not need R/C parts to create a timer. There's a built-in 4-MHz oscillator (1% accuracy) time base that you use to derive whatever frequencies you need. Depending on what you're doin' with the '4093 you can probably create the same logic in software in the PIC program.

Regards, Mike

 

[colin55]

You have to also consider pushing the button 10 minutes after the first push to modify the result.

You can also add a beep to let you know what the PIC is doing or even a LED to blink and let you know.
These are all important features when you are waiting 90 minutes for an outcome.
I have the exact project you need but mine is called FISH-SHOP TIMER and it times in minutes up to 15 minutes for cooking meat, fish etc and is intended to be reset when 10 minutes has expired. It's handy to get a beep every minute (1 beep for every 30 minutes) to let you kow the timer is working). This feature can be activated by a push-button at any time.

These are all possible with a PIC.

 

[Mike - K8LH]

Those are issues that JR and I need to discuss. I was going to suggest a piezo speaker for switch press beep feedback and "short" and "long" switch detection, the latter being used to cancel or abort the timer/output sequence.

Did you want to post your version of the program for comparison Colin?

 

[Mike - K8LH]

Hi mike, are you serious about helping out this weekend? let me know I have also written a description of another part of the circuit that if you want can also be converted to Pic. ,waiting for your reply..jr from daytona beach florida. i need some one to program this for me, should I purchase a programmer, if so which one would you recommend...thanks again, mrtelephone@earthlink.net.....

Hi JR,

I would be happy to help. I notice that Mike (Pommie) also offered to help and he's an excellent programmer.

A PICKIT2 or compatible (Bill's Junebug) programmer is a good choice.

I need some details. For example, how precise does the 30/60/90 minute timing need to be? The internal oscillator on the 10F200 will be more precise than an R/C timer but not as precise as a crystal oscillator. If you need better precision then we would need to use a different and slightly more expensive 8-pin PIC and a crystal and this might effect your plans. What is the pulse duration?

My email address is k8lh(at)arrl.net

Regards, Mike

 

[jr2233]

hanks for answering colin55, my requirement would not need an E nor a beep because exactly how I describe it, is how it must function because it will be included in a larger circuit that already has indications. this smaller circuit only adds additional "on" time to the rest of the circuit. Now that I am considering using a Pic to build the smaller time extender circuit (the one I describe in this forum), I am also wondering if it would not be easier to also use the same Pic or a larger Pic to just build both parts of the circuits. As long as it does not take much time. If someone is availlable, I am located in central florida. The complete circuit is made up of 3 timers, 3 inputs, 2 outputs and 2 Led indications. Thats it for I/O's , I have a description written up... hope someone can help...jr

 

[Mike - K8LH]

JR,

Got your email and will study those specs' and get back to you...

Mike

 

[jr2233]

Hello Mike, you don't seem to be replying to my emails. Let me know if you are. I have a block diagram I made out on the circuit. jr