Set a pin high for a second every day...?

C

ChedderCheeser

Senior Member
Hi guys. I am planning to make a little project that will activate a counter module every day. How can I set up my 08M to pulse the pin every DAY? ex.

Code: 
main:
    pause ONE-DAY
    high PIN
    pause 1000
    low PIN
goto main
THX!
 
S

Svejk

Senior Member
Do you have a paticular time of day in mind? If not, you can use the night to day transition to set your pin interfacing with a simple LDR.
 
M

manuka

Senior Member
CC: A simple approach could just use cascaded WAITs for 86400 seconds (being 60 seconds x 60 minutes x 24 hours). BUT all the usual request background info. is REALLY first needed. Hence -how accurate does it have to be? Will the temperature be constant? Approx.what time of the day/night does it switch? Indoor/outdoor (& if the latter can the sun be "seen")? Will accumulated errors be an issue? What budget? Battery powered ?

Requests for technical help often NEED excrutiatingly FULL details, otherwise it's perhaps like turning up to a supermarket & bluntly saying "I want food"...
 
Last edited:
T

tracecom

Senior Member
I think this will do what you want, but there are at least three problems: first, it has some inherent inaccuracy because of the PICAXE clock inaccuracy; second, the PICAXE is not available to do anything else; and third, the PICAXE won't respond to programming while it's paused. Better to use a RTC.

Code: 
main
	high 2
	pause 1000
	low 2
	for b1 = 1 to 24	'Sets number of hours to pause.
		for b0 = 1 to 60	'Sets number of minutes to pause.
			pause 60000	'Pauses for 60 seconds.
		next b0
	next b1
goto main
 
M

MartinM57

Moderator
ValueAdd said:
If that is the case, then Microchip App Note AN521 :interfacing to AC PowerLines" would be worth reading:
http://ww1.microchip.com/downloads/en/AppNotes/00521c.pdf
Click to expand...
...if only to note that the PIC(AXE) circuit is one resistor away from live mains.

@ChedderCheeser - please don't do it this way. Period.
@ChedderCheeser - please respond to post #3 or else the collective will come up with even more solutions to no real requirements ;)
 
S

srnet

Senior Member
MartinM57 said:
@ChedderCheeser - please don't do it this way. Period
Click to expand...
Indeed.

That type of 'solution' is for the experienced, and requires additional safety precautions.

Not difficult mind to use a transformer from a disgcarded linear power supply (as in wall wart) and get the AC from the low voltage side of the transformer, that would be a LOT safer.
 
hippy

hippy

Ex-Staff (retired)
I had to face this challenge when wanting to use a PICAXE to 'push a button' on a digital picture frame once a day at a fixed time.

Accumulated drift is a problem without a crystal, no RTC and no mains cycles to count, but shorter periods to triggering were tolerable in my case. I ended up using a plug-in mains timer so the picture frame is turned off over night ( an environmental benefit in itself ), when it turns on the PICAXE program is then quite simple - delay, trigger button push, sleep forever.
 
W

westaust55

Moderator
srnet said:
Indeed.

That type of 'solution' is for the experienced, and requires additional safety precautions.

Not difficult mind to use a transformer from a disgcarded linear power supply (as in wall wart) and get the AC from the low voltage side of the transformer, that would be a LOT safer.
Click to expand...
I concur.
Would also suggest that the initial post by MPep stated "derived from" as opposed to "directly connected to" thus the suggestion should b seen as a guideline as the transformer into. Say 7805 regulator would still be at too high a voltage for direct connection of ELV levels to the PICAXE chip.

Then in this world of litigation such warnings as above become a necessity.
 
Last edited:
P

Paix

Senior Member
The Borg collective has detected the frenetic creativity that is CheddarCheese's thought process and are drawing up plans to harness this powerhouse of energy by a process of assimilation. Stand by for an 08M2 implant to connect you to the greater interstellar network Chedder'.

I suspect that testing and calibrating process for your DAY delay might not be fast enough for your agile mind. :) If you could bottle enthusiasm and imagination as a cocktail and flog it, you could become an entrepreneurial millionaire . . .

Not only that, your name could become a household name in the food and drinks business (couldn't help myself).:)

Have a good summer.
 
C

ChedderCheeser

Senior Member
Post #3 - Well, It is going to be indoors. Probably out of reach by the sun. Powered by an ac-dc converter. A good one. Temperature will be constant ish.. it may vary a bit... by like 5 degrees at the most. I dont need it to be at any specific time of day. Preferably at like 4:00 AM. I think that that would actually work fine for what I am doing... Maybe I should just.. power up the circuit at 4:00 AM so that that would be the time it does the next pulse? Also, thanks for the code! I think I will use it. I'll let you guys know how it goes.
 
J

Jamster

Senior Member
If you have acsess to an RTC (DS1307) then you can use this code:
Code: 
 symbol seconds=b0
 symbol mins=b1
 symbol hour=b2
 symbol temp=b3
 symbol day=b4
 symbol date=b5
 symbol month=b6
 symbol year=b7
 
 ;set these to the trigger hour
 symbol trighour=4
 symbol trigminute=00
 
 i2cslave %010000,i2cslow,i2cbyte
 
 ;REMed out line below is to set current time
 ;   min|hour
 'writei2c 1,($16,$20)
 
 do
 pause 1000
 readi2c 1,(mins,hour)
 
 ;Convert values to something usable
 temp = mins AND %00001111
 mins = mins AND %11110000 * 10 / 16 + temp
 
 temp = hour AND %00001111
 hour = hour AND %11110000 * 10 / 16 + temp
 if mins=trigminute and hour=trighour then
  ;TRIGGER EVENT HERE
 endif
 loop
 
erco

erco

Senior Member
Use a cheap wristwatch with a daily alarm signal: cheaper, easier, & far more accurate.
 
C

ChedderCheeser

Senior Member
tracecom said:
I think this will do what you want, but there are at least three problems: first, it has some inherent inaccuracy because of the PICAXE clock inaccuracy; second, the PICAXE is not available to do anything else; and third, the PICAXE won't respond to programming while it's paused. Better to use a RTC.

Code: 
main
	high 2
	pause 1000
	low 2
	for b1 = 1 to 24	'Sets number of hours to pause.
		for b0 = 1 to 60	'Sets number of minutes to pause.
			pause 60000	'Pauses for 60 seconds.
		next b0
	next b1
goto main
Click to expand...
How accurate is it?

Jamster said:
If you have acsess to an RTC (DS1307) then you can use this code:
Code: 
 symbol seconds=b0
 symbol mins=b1
 symbol hour=b2
 symbol temp=b3
 symbol day=b4
 symbol date=b5
 symbol month=b6
 symbol year=b7
 
 ;set these to the trigger hour
 symbol trighour=4
 symbol trigminute=00
 
 i2cslave %010000,i2cslow,i2cbyte
 
 ;REMed out line below is to set current time
 ;   min|hour
 'writei2c 1,($16,$20)
 
 do
 pause 1000
 readi2c 1,(mins,hour)
 
 ;Convert values to something usable
 temp = mins AND %00001111
 mins = mins AND %11110000 * 10 / 16 + temp
 
 temp = hour AND %00001111
 hour = hour AND %11110000 * 10 / 16 + temp
 if mins=trigminute and hour=trighour then
  ;TRIGGER EVENT HERE
 endif
 loop
Click to expand...
Very nice. I sadly dont have it though. I could get it...

Use a cheap wristwatch with a daily alarm signal: cheaper, easier, & far more accurate.
Click to expand...
Good plan... but.. I dont REALLY need a picaxe for that do I? Unless I wanted to trigger like.. a servo or something?
 
S

srnet

Senior Member
Not sure I understand the difficulty here.

At the time of day you want the pulse to be sent, press a button connected to the PICAXE where a simple program scanning for the switch sends the pulse/
 
T

tracecom

Senior Member
ChedderCheeser said:
How accurate is it?
Click to expand...
It varies from one PICAXE chip to the next. I had one 08M that was very close: it took 21604 seconds to complete a pause routine that was supposed to be 21600 seconds. But even that 4 second difference in six hours translated to 16 seconds per day, or 97 minutes per year.
 
J

Jamster

Senior Member
Yes the code will definatly work with that, I have the DIP version so can help with any debuging if needbe.

P.S. Lazy...:D
 
M

MartinM57

Moderator
ChedderCheeser said:
Post #3 - Well, It is going to be indoors. Probably out of reach by the sun. Powered by an ac-dc converter. A good one. Temperature will be constant ish.. it may vary a bit... by like 5 degrees at the most. I dont need it to be at any specific time of day. Preferably at like 4:00 AM. I think that that would actually work fine for what I am doing... Maybe I should just.. power up the circuit at 4:00 AM so that that would be the time it does the next pulse? Also, thanks for the code! I think I will use it. I'll let you guys know how it goes.
Click to expand...
The most important request in post #3 is accuracy - which also needs to be extended to drift


e.g. +/- 2 seconds per day, zero average drift
e.g. +/- 2 minutes per day, +/- 30 minutes a month drift
etc

So what are we talking about for this "counter" - just an elapsed days counter, right?
 
hippy

hippy

Ex-Staff (retired)
There's merit in using a wristwatch, though I'd go for a digital alarm clock. First it's easy to set and adjust, it's usable as a real world clock, and if using an in-built piezo for triggering you'll probably want to use a PICAXE to turn that one minute or longer signal into something you can use for what you are controlling so there's still a PICAXE project element to it. If you're lucky you might find a radio controlled alarm clock cheap - last one I found in a garage sale was 25c.

So really it's a toss-up between a DS1307 and the bits that needs or a wristwatch / alarm clock.
 
S

srnet

Senior Member
I would go for the mains timer approach, as mentioned earlier.

Simple, cheap (£4ish delivered off eBay), accurate, useful for lots of other things too.
 
M

meridian

Member
erco said:
Use a cheap wristwatch with a daily alarm signal: cheaper, easier, & far more accurate.
Click to expand...
I did that years ago! Used a watch with alarm, sat in on a mic which went to a counter chip, can't remember now. After 10 beeps, relay went on, power to radio or something.

paulr
 
You must log in or register to reply here.
Top