OFF-the-wall idea for momentary ON switch

[MrDEB]

Looking to build a digital kitchen timer that shuts off after timing out and/or a 10 second delay waiting for user input.
Here is the screenshot of the on/off section of the kitchen timer. Going to use an 18Fxxxx pic
maybe need a diode on the pic output pin to prevent applying voltage to the unpowered pic.

unpowered pic?

 

[tumbleweed]

It might help if we knew what the "5V battery" was in the schematics...

 

[Nigel Goodwin]

It might help if we knew what the "5V battery" was in the schematics...

Obviously one of those 5V batteries you buy from the local store

 

[MrDEB]

The enclosure I have has 4-AA batteries, so it is 6 volts with fresh batteries.
Made a correction to the ICSP as per post #53
Now, I am waiting for some fresh solder. My solder doesn't seem right. It is just like flakes onto the circuit board while soldering in a bunch of Mosfets for my Margarita sign circuit board. I applied flux and rechecked the temp setting on the iron. Maybe the iron needs some attention? Just touching the solder to the tip, it melts just fine.
Does solder get old?

 

[For The Popcorn]

MrDEB I am truly amazed at your ability to miss the most pertinent points. You definitely have a knack.

Solder doesn't "go bad". Pay the price for Kester 44, 63/37 rosin core and it will work well.

(edited to correct early morning brain fade)

 

[tumbleweed]

Obviously one of those 5V batteries you buy from the local store

Silly me. I see them now... they're right next to the AC batteries.


MRD - you could use one of those TPS load switches to control the LCD backlight if you wanted to extend the battery life. 6V is a bit on the high side, but at least it doesn't exceed the absolute max.

 

[Nigel Goodwin]

Silly me. I see them now... they're right next to the AC batteries.

Make sure you get the right frequency ones

 

[MrDEB]

I ordered a roll of solder from Jamco #141786
it is 60/40 rosin core

 

[For The Popcorn]

I've learned by experience that when it comes to solder, Kester is the answer. To borrow T-Mobile's slogan, it just works.

 

[ZipZapOuch]

I've learned by experience that when it comes to solder, Kester is the answer. To borrow T-Mobile's slogan, it just works.

Because not all 60/40 alloys are the same?

 

[MrDEB]

Yes, I should have ordered the Kester brand.
Been contemplating this stupid project and thinking "Maybe:" I need to add an ON button so then the buttons would be 6 unless I can use the START TIMER button to enable the timed latch circuit.
Depress to enable the timed latch circuit then use the same button to start the timer?
NOTE the micro would be powered ON after the timed latch circuit is enabled.
Any ideas

 

[MrDEB]

updated schematic.
Thinking maybe have a green LED light up after 10-15 seconds after last user input to correct time event desired then I could eliminate the START_TIME BUTTON

 

[For The Popcorn]

MrDEB , how about trying to make all the needed changes & corrections to your schematics before posting them, rather than adding some and apparently saving others for later? Once again, you have so many different versions posted ain't nobody can keep track of what's what, including you.

In post #45, the latch circuit is drawn correctly.

In post #50, you screwed up the latch circuit. In post #54, I pointed that out. Yet your latest schematic hasn't corrected that error.

In post #52, Pommie pointed out the wiring error on your switches. Not corrected in your latest schematic.

I also suggested adding a two pin header to bypass the latch circuit during programming and dev, which hasn't been implemented or acknowledged. If you don't understand something, rather than blowing it off, ask why it's important.

Yes, you have made some of the suggested changes (ICSP V+ connection and LCD control lines). Do you expect a gold star for doing so?


I don't mean to be harsh, but I just spent an hour comparing schematics to figure out what changes have been made, fixed or broken. It would be useful to say exactly what you've changed in each schematic. You'll keep track and commenters will know w/o searching.

 

[ZipZapOuch]

It might help if we knew what the "5V battery" was in the schematics...

Obviously one of those 5V batteries you buy from the local store

Likely one of the 5v power bricks (a.k.a. "back up batteries") that are so popular these days with DIYers - easily recharged with a USB cable. Available in a wide range of capacities and from more reputable dealers like Anker, Samsung and more. Way safer than dealing in loose lithium batteries with questionable charger circuits.

And, yes, they are available at many local stores - another good point.

 

[MrDEB]

oops grabbed the wrong schematic.
Here, hopefully final.
white LED = waiting for button press
green LED = timer is done
yellow LED = battery low
hopefully it is all correct

 

[For The Popcorn]

 

[For The Popcorn]

 

[For The Popcorn]

 

[MrDEB]

YES while laying in bed this morning, It dawned on me about the left side of the switches DUH
As for the bypass during programming, this is going to be mounted on a stripboard. IF it works out, then yes will add on a PCB design.

 

[For The Popcorn]

YES while laying in bed this morning, It dawned on me about the left side of the switches DUH

It's fortunate you discovered the error. The board wouldn't have worked as you drew it.

 

[MrDEB]

I realized that
Working on some code, Call it an outline.
A routine to monitor portB. Any input.
After the user inputs the desired TIME, the pic automatically starts timing after 10-15 second delay.. if no changes(input) to DESIRED TIME on portB (the green LED is enabled. tHINKING ABOUT 10-15 SECONDS delay before the green LED is enabled indicating the timer is counting down from the desired time to zero.
User sets desired TIME but before the timer starts the user changes the desired time BEFORE THE GREEN led IS ENABLED.
User inputs 5 minutes but before the green LED (TIMER STARTS) the user decides they only wants 4 minutes.
MAYBE REALLY DON'T WORRY ABOUT THIS?
using SF basic