Question for problem solvers #2

[georpo]

Hi all.
I know this is not the right place to ask.. but please bare with me.

I am building a device that sprays perfume during the day in predefined intervals and hours.

For example:

Prog1: 08:00 - 14:00
Prog2: 17:00 - 20:00
Prog3: 21:00 - 22:00

I convert all starting and ending times to seconds (Hour*3600+Minute*60) so the above is:

Prog1: 28800 - 50400
Prog2: 61200- 72000
Prog3: 75600- 79200

Now the problem is that I have to make a sanity check if the programs overlap (common spray times). For example:

Prog1: 08:00 - 14:00
Prog2: 09:00 - 20:00

or

Prog1: 08:00 - 14:00
Prog2: 07:00 - 15:00

I have totally burned my mind trying to figure this out...so any help appreciated
_________________
George.

[PCM programmer]

Use Google to search for this:

[georpo]

Thanks for the stackexchange tip.
_________________
George.

[temtronic]

Just a comment on the 'times controller' ...

Converting times into seconds will need 32 bit variables and maths ( 86400 seconds in a day).

If you can afford to use '1/4 hour times' (8:00,8:15,8:30,9:00 ) then on/off times can be stored in a byte, actually 7 bits. The 8th bit can be used as a 'flag' to control an operation, like 'pulse the perfume valve'.

I've used this method for 30+ years for remote control HVAC systems. Back then we didn't have PICs,memory was costly and really no need for 'second by second' control.

If the project is a 'one-off' or 'home use' you can afford a bigger PIC, but if it's a commercial product where the smallest (cheapest) PIC has to be used, then using my method greatly reduces memory requirements AND speeds up the main() program loop.


Jay

[allenhuffman]