Automatic turn off

[AMay]

I have finished my timer project, and I think it came out pretty well. Pictures attached. As usual, a project starts out very simple, but when you find it necessary to accommodate humans, things get more complicated.

First, I determined that the user needed to see some continuing action for reassurance that the unit was working, so I added a flashing led. Also, some means of resetting, or starting over, so you don't have to wait 'till the time runs out to begin again. This was done by the program.

I found that the sonalert buzzer needed to be glued to the case, lined up with matching hole. I first tried putting it on the circuit board, but the sound was muffled too much. I used Goop glue, which seems to stick to everything.

I liked the result so much, I made two. One to pass along with a 9 volt battery, and one to keep. The keeper has a 3.6 volt lithium battery with wire leads soldered to the board. I figure that the lithium battery will last over 1000 hours. The PIC uses about 1.7 ma, and the buzzer and led are not on very much of the time.

The off current is not measurable by the equipment available to me. My Fluke meter reads .1- .2 ua, either in or out of the circuit when it is "off."

I appreciate the help and advice I have received. Thanks to all those who offered suggestions.

AMay

[Leonardo]

Hello,

Where I connect the load in the circuit done by melanie.

Thanks

[Melanie]

The 'load' is connected between the Collector of Q1 and 0v.

[Dwayne]

I ended up using a SPST switch on mine....

They sell these dirt cheap all over the place... with 20 MILLs and less to operate...

I put the switch to make contact across the Terminals, and as soon as the contact is made, the PIC stuck 20 mills across the load to keep it on. The you can do whatever you want....and the PIC will turn it off 100 percent. run 3 1.5 volt batterys and presto...

Attached is a image... Please do admire my artistic abilities...<chuckle>

Dwayne

[mister_e]

i hope one day i'll be able to do nice schematic like that. I really need to trash my P-Cad and use your software instead

[Leonardo]

Hello mister E

I am using PICBASIC COMPILER 1,45 and the following one I cosay does not work, I want to me to ignite the LED in pin2 by 1 minute and as soon as another minute is extinguished and continue the sequence but does not work to me, some suggestion.

I am using a PIC12F675.

Thanks


'code

Symbol Mi = B0
Symbol Se = B1

TOP:
Dir2 = 1 ' make Pins 2 and 1 outputs
Dir1 = 1

Pin2 = 0 ' turn off lamp - off or 1 minute
For Mi = 1 to 1 'minutes
For Se = 1 to 60 ' seconds
Pin1 = 1 ' test LED
Pause 500
Pin1 = 0
Pause 500
Next
Next

Pin2 = 1 ' turn lamp on - on for 1 minute

For Mi = 1 to 1 ' minutes
For Se = 1 to 60 ' seconds
Pin1 = 1
Pause 500
Pin1 = 0
Pause 500
Next
Next

GoTo TOP

i hope one day i'll be able to do nice schematic like that. I really need to trash my P-Cad and use your software instead

[Dwayne]

Hello leonardo,

I think I understand what you are trying to do... Try this...This is assuming your previous code compiles... I do not have PB, I only have PBP.

Dwayne

'code

Symbol Mi = B0
Symbol Se = B1

TOP:
Dir2 = 1 ' make Pins 2 and 1 outputs
Dir1 = 1

Pin2 = 0 ' turn on lamp - 1 minute
For Mi = 1 to 1 'minutes
For Se = 1 to 60 ' seconds
Pin1 = 1 ' test LED
Pause 500
Pin1 = 0
Pause 500
Next
Next

Pin2 = 1 ' turn lamp on - on for 1 minute

For Mi = 1 to 1 ' minutes
For Se = 1 to 60 ' seconds
Pin1 = 1
Pause 500
Pin1 = 0
Pause 500
Next
Next

GoTo TOP

Try something like this:

'code

Symbol Mi = B0
Symbol Se = B1

TOP:
Dir2 = 1 ' make Pins 2 and 1 outputs
Dir1 = 1

Pin2 = 0 ' turn off lamp -  1 minute
Pin1 = 1' Turn on Lamp 
For Se = 1 to 60 ' seconds
Pause 1000
Next

Pin2 = 1 ' turn lamp on - on for 1 minute
Pin1=0 'turn Lamp off for 1 minute.

For Se = 1 to 60 ' seconds
Pause 1000
Next

GoTo TOP

[TK5EP]

Did not find your "final solution",
Could you post it again ? It might interest other people too.

Thanks,

I have finished my timer project, and I think it came out pretty well. Pictures attached.

AMay

[AMay]

The attachment to my original message got lost it seems, so here it is.

[Ioannis]

The attachment to my original message got lost it seems, so here it is.

In the past I tried with mosfets but the results were disapponting.

Then I used an PNP transistor much like Melanies post. I think that circuit as was presented by Melanie is the best up to this moment.

Ioannis

[Acetronics2]

Hi

Why not use a simple regulator with Enable pin ??? ( i.e LM 2941 ...)

Alain

[Ioannis]

Hi

Why not use a simple regulator with Enable pin ??? ( i.e LM 2941 ...)

Alain

Because at least 300uA is needed when in OFF state!

Still the previous circuit with an PNP like BC557 or BC856/7/8 is the #1.

Ioannis

[Acetronics2]

Ioannis,

this was an Example .... have a look to other brands too ( Micrel 29xxx ( 1µA ) ... etc, etc ).

Alain