x10 MS13 as a dusk/dawn sensor

[Commodore White]

I have read that the MS13 reports light level as well as motion detection.

Is the light level reported as a value I can compare against a datum to decide if its dark enough to be dusk or light enough to be dawn. I need this because the software I use has no idea if the day is dark and overcast so gets dusk and dawn times wrong more often than right..

It goes without saying (but I'll say it anyway) that I intend to have the MS13 outside (but sheltered from rain)

Regards' Peter

[Rene]

The MS13 only sends an on or off signal indicating dusk and dawn.

[AshaiRey]

To be more precies.
If it getting dark at the location where the MS13 stands then you get a signal and an other one when it get light again. This can happen multiple times aday depending on light levels. Just On/OFF, no level information

[Bwired]

Also the dusk dawns sensor is very unreliable, it only sends the on off a couple of times and it is missed a lot upon receiving.

[AshaiRey]

Also the dusk dawns sensor is very unreliable, it only sends the on off a couple of times and it is missed a lot upon receiving.

I don't agree about that.
Because its a batterij device it sends it state with intervals but that can be as short as a few minutes at max.
I seldom miss a signal from is however in all honesty i have to say that i paired a few together in a event with an OR statement so if only one trigger is received it's oke.

[Bwired]

Not with my MS13, when dusk or dawn occurs, it only send a couple of packets and then you have to wait for next dusk dawn.
If you have a larger house and lots of x10 rf its not reliable for dusk dawn, at least not in my situation.
With the motions part it keeps on sending packets pauses a small time and sends again if there is motion.

[AshaiRey]

So you are saying that the dusk/dawn sensor can't be triggered again within 6 hours or so to say?

The ones i have behave like light/dark sensors and not related to a particulair time of the day.
When it is getting dark it signals. If it is getting light it signals again and that over and over again.
I use them also to trigger the lights on in a room when it is getting to dark there due to dark clouds at day.
Or to turn on the light under the kitchen cabinets on a dark day and you work there. When there is enough light they won't trigger.

[Bwired]

When you miss the first dark or light setting there is no hartbeat

[AshaiRey]

No, that is correct. It only trigger again when the light level change again from light to dark or visa versa
Ps, This would be to most complete answer on the forum by now.

[SolidReason]

Note that you can tweak the dusk/dawn sensor sensitivity by replacing one of the resistors by a potentiometer. I wasn't pleased with the default dusk/dawn threshold and applied the change as described here, works remarkably well.

[Commodore White]

Thanks for this, guys. It sounds as though I shouldn't rely on the dawn/dusk sensor since I might miss signal. Perhaps a winning strategy might be to use computer time of day to tell me when it should be dark but use a sensor to tell me it it gets dark early. I acan extend dawn by switching off the outside lights when the sensor says so and always switching off 1-hour (say) after the computer thinks its dawn in case I missed the sensor. Anyways, something else to play with.

AshiRey said the sensor might trigger several time I guess because clouds come over. Surely, there is some element of hysteresis (sp?) To prevent this. AshiRey, which ones do you use, are they more affordable than the MS13 for saturation use?

[AshaiRey]

AshiRey said the sensor might trigger several time I guess because clouds come over. Surely, there is some element of hysteresis (sp?) To prevent this. AshiRey, which ones do you use, are they more affordable than the MS13 for saturation use?

Simply said they give a signal when it get dark (litteraly) and they give a signal when it gets light again. So only when the light level changes from dark to light and visa versa. Nothing fancy here. If it is getting to dark in a room due to heavy clouds then a signal is send only if the previous state was 'light'
I don't know how to say this more clearer.

I use MS13's ordered in the US. I replaced the 310Mhz transmitter for a 433Mhz transmitter. Using 10 of these this conversion saved me a lot.
Search the forum for more details on how to do this (author is according me esschenck)

[Commodore White]

Thanks AshiRey for you helpful comments. I realise perfectly how the sensor might work in varying light conditions. What I was trying to do was take in to account some peoples assertion that the "its got dark" or the "its got light" signal might get missed.

I've done several searches but can't find the reference to how to convert the ms13 from one frequency band to another but did find several references on how you can repurpose the light sensor stuff as a door/window open detector - interesting stuff..

Thanks again

[Commodore White]

Drat, no sooner that I hit the POST button did I find the reference to which you were referring - annoying or what? Shame I couldnt edit the post because everything I type gets moderated for some reason - sigh

[Digit]

After the 10th post you'll be fine