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OA47

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Joined: 11/04/2012
Location: Australia
Posts: 1036

Posted: 11:48pm 22 Jan 2026

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I am using many displays that are active 24/7 and would like to lower the backlight during evening hours. I have used a test to look for 07:00:00 and 19:00:00 time stamps which works OK but occasionally that time stamp is missed due to other operations of the program. I would like to test if the time is past 07:00:00 and 19:00:00 to reduce or increase the backlight. I vagally remember discussions of an EPOC command but I can't find any mention in the handbooks. Would this be the direction I should head?

Regards
OA47

Andy-g0poy
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Joined: 07/03/2023
Location: United Kingdom
Posts: 84

Posted: 12:02am 23 Jan 2026

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EPOCH(DATETIME$)

and NOW
Print EPOCH(NOW)

Page 187

DATETIME$(n) returns the date time string fromthe epoch number n

page 185

Using the pdf manual
MMBasic BASIC Interpreter
Ver 6.01.00

Andy

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6455

Posted: 12:58am 23 Jan 2026

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Time$ is a string and you can compare strings

'
IF TIME$ >= "07:00:00" AND TIME$ < "19:00:00" THEN
backlight = 100
ELSE
backlight = 20
ENDIF

VK7JH
MMedit

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 3016

Posted: 02:25am 23 Jan 2026

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That is clever, easier than Epoch.

> TIME$ = "06:55" : ? TIME$ >= "07:00:00" AND TIME$ < "19:00:00"
0
> TIME$ = "07:05" : ? TIME$ >= "07:00:00" AND TIME$ < "19:00:00"
1
> TIME$ = "18:55" : ? TIME$ >= "07:00:00" AND TIME$ < "19:00:00"
1
> TIME$ = "19:05" : ? TIME$ >= "07:00:00" AND TIME$ < "19:00:00"
0
>

> night = 19*60*60
> day = 7*60*60
> aDay = 24*60*60
> if epoch(now) mod aDay > night then backlight 10
> if epoch(now) mod aDay > day then backlight 100

Edited 2026-01-23 12:29 by phil99

greybeard
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Joined: 04/01/2010
Location: Australia
Posts: 178

Posted: 02:45am 23 Jan 2026

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As a general guideline for programming limit or range logic I'd suggest checking for > or < as appropriate unless circumstances preclude doing so. ie not just = to.
A lot more people can program when the real world behaves as they expect their virtual world to behave. A good programmer should strive to program for when the real world is real and things don't behave in a virtual manner. ie program for the worst case, not the best case especially if your version of logic says it can't happen, it will.

OA47

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Location: Australia
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Posted: 03:27am 23 Jan 2026

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Thankyou all, I will use the string comparison.

OA47

PhenixRising
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Joined: 07/11/2023
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Posted: 09:18am 24 Jan 2026

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"your version of logic" 🤣😂🤣😂

Mixtel90

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Joined: 05/10/2019
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Posts: 8568

Posted: 11:23am 24 Jan 2026

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This is only one of the reasons why it's difficult to properly check your own code. You *know* that a particular logic stream is correct when it will stand out like a beacon to someone else that it's wrong. :(

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

PhenixRising
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Posted: 06:41pm 24 Jan 2026

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Mixtel90 said This is only one of the reasons why it's difficult to properly check your own code. You *know* that a particular logic stream is correct when it will stand out like a beacon to someone else that it's wrong. :(

Andrew_G
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Joined: 18/10/2016
Location: Australia
Posts: 874

Posted: 09:30am 27 Jan 2026

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Hi Graeme,
You kindly gifted me some monitors and cables via Big Mick a few months back. Thanks.

Another solution to your issue is to use a Light Dependant Resistor (LDR) (e.g. Jaycar # RD3480) to measure the ambient light. I use them on "everything", especially in my sleeping quarters/my side of the bed.
With a little bit of calibration you can get three levels, bright/normal/dark, and set BACKLIGHT accordingly.
Use SETTICK to check the resistance every second and it responds well.

Happy to post more details.

Cheers,

Andrew

OA47

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Posted: 01:07am 28 Jan 2026

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Quote You kindly gifted me some monitors and cables via Big Mick a few months back. Thanks

Andrew you are very welcome. It is a bit of a pity that so much stuff had to be sent to waste but that was the way it was.

OA47

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