Timer and LED PWM with 3a 12VDC power

[davisgraveyard]

I would like to automate our LED lighting for our yard display with a simple controller.   We have just under 3a of 12VDC LED's in our display that are currently hooked up to a daylight timer set a 4hrs and a 2.5a 12VDC power supply outdoors.  There are 2 problems I am trying to solve with this setup.  1.  I want to change the number of hours per day that the lights stay on  S-Thu dusk  to 10pm and Fri/Sat dusk  to 11pm.  2.  I would like to have the  lights fade down when turning off instead of switch off it is ok if they switch on since at dusk they can't be seen anyway.

Is this possible with any of the EFX-TEK products?



 

[JonnyMac]

With a Prop-SX and some additional circuitry (high current transistor/FET to switch/pwm the current) you could do it.  Lots of custom work, though.

We're working on a new product that can control eight, high-current outputs and is customizable (i.e., can be reprogrammed).  I can't say much more about this but when it's ready I'll point out how this board could be used with a firmware modification to do what you want.

[davisgraveyard]

Why is it that every time I think of something cool I'd like to do with an EFX-TEK product the solution is on the horizon or just a custom tweek away?

The PWM would be a nice to have.   What I'm really after is a simple sprinkler system style timer (Day, time on, Time off) and the ability to turn on/off 3A 12VDC.

I think there is a more sophisticated lighting timer you can buy for christmas lights that lets you program each day of the week and of course it is a 110V switch so you can just plug your 12VDC power supply into it but I think they are pretty expensive not that the EFX-TEK solution wouldn't be. 

For the timer I was thinking it would be cool if you could seed your program with the year and timezone and it could figure out sunset and then you could have your lights turn on when that happens without a photo sensor. 

I patiently await the best solution.

[JonnyMac]

In all seriousness, we try not to sit still.  As our customers want to do more we try to provide more.  The product I'm talking about will replace the DC-16 -- and has a bunch of cool features (our friends at Disneyland are going to put it use as soon as we hand it to them).

You can certainly customize a Prop-SX and add some external hardware, but the new product will handle the current requirement you have and can be reporgrammed to do whatever you want.  That product doesn't include a real-time-clock, so you may want to use a "dusk detector" circuit (CdS photocell and cap) so that the lights come on at the correct time.  It has a bank of input switches so you could set your present day via those switches and then power-up -- so long as power wasn't lost the you'd be okay.

[JonnyMac]

Now that I think about it, if you attach a serial LCD (to the serial port normally used by the Prop-1 or Prop-2) and some buttons to the manual inputs, you could do EXACTLY what you want.  The device uses the Parallax Propeller chip (the heart of the AP-16+) which means you could program the time and have it keep track (so long as you don't lose power).

As I stated above, Disneyland is excited about this -- they will use it as is (it is DMX-compatible out-of-the-box) and will customize it for applications where they have typically used the Prop-SX.

[davisgraveyard]

Sounds like a great addition to your product lineup.   Don't get me wrong I wasn't complaining.  Just wafting philosophic about how this always seems to happen to my ideas.  "Just wait...we have something coming that will be perfect".

I looked around and a simple 7 day 110v outdoor lighting Timer is pretty cheap.  I could probably hook that to a relay switch that could then toggle the 3A worth of LED lights up or down.

I guess I will stick with the timer for now.

[JackMan]

I picked up a couple of Intermatic DT300 digital timers at Menards a few months back (link below will show what it looks like) for $4 each. Great little timer, 20 on/off settings for each day, 7-day independent or multiple, on/off settings to the minute, very accurate time keeping with an internal battery that charges when plugged in. This would work nicely for your custom on/off requirements but it won't dim.


http://cgi.ebay.com/Intermatic-Digital-Lamp-Timer-Model-DT300CH-NIP_W0QQitemZ310197433363QQcategoryZ20509QQcmdZViewItem#vi-content