Simple Digital Programmable Timer?
garyg
Posts: 420
I like to keep things simple.
Since about year 2002, I've been using a simple programmable timer that could be purchased for
approx. $20.00.
The Timer is Intermatic Model DT17.
You could program up to 14 on/off cycles per day.
These appear to have gone by the wayside.
I have 6 of these timers operating different functions in my garden at different times and days.
Lately I've started to look for a simple timer that would work like the Intermatic timer but,
would be battery powered.
All I really need is accurate clock with several outputs happening per day.
Does anyone know a source for a simple timer with output?
I have an ongoing garden pest deturrent quest.
My latest gizmo is a Garden Owl that uses a Parallax PIR sensor and Radio Shack 20 second sound card
and glowing LED eyes to chase nighttime pests out of my garden.
I've thought about building a timer with LCD display using a Parallax Prop, but I'm thinking that
somewhere out there, someone manufactures a simple programmable timing device that would work for
simple control.
I'm starting to ramble here, so I'll end here.
Any suggestions or comments will be appreciated.
Thanks
Since about year 2002, I've been using a simple programmable timer that could be purchased for
approx. $20.00.
The Timer is Intermatic Model DT17.
You could program up to 14 on/off cycles per day.
These appear to have gone by the wayside.
I have 6 of these timers operating different functions in my garden at different times and days.
Lately I've started to look for a simple timer that would work like the Intermatic timer but,
would be battery powered.
All I really need is accurate clock with several outputs happening per day.
Does anyone know a source for a simple timer with output?
I have an ongoing garden pest deturrent quest.
My latest gizmo is a Garden Owl that uses a Parallax PIR sensor and Radio Shack 20 second sound card
and glowing LED eyes to chase nighttime pests out of my garden.
I've thought about building a timer with LCD display using a Parallax Prop, but I'm thinking that
somewhere out there, someone manufactures a simple programmable timing device that would work for
simple control.
I'm starting to ramble here, so I'll end here.
Any suggestions or comments will be appreciated.
Thanks
Comments
The nature of micro-controllers are to do things very quickly and you appear to want a 24 hour timer of some sort. So to use a Propeller, you would would primarily have to create delays to provide you with a much slower tick.
And then, there is the addition of input and display interfaces. An LCD can be attached. The QuickStart already provides 8 touch switches.
I presume you are asking here because you want to build your own rather than try to locate a commercial replacement. There are lots of commercial timers that run on 120VAC and use a synchronous motor to time a 24 hour cycle... they will even directly turn on and off AC.
Your Intermatic may no longer be available, but something similar is. If that is what you want... visit your local hardware store and ask about a timer to turn on and off lights when you are leaving your home vacant for two weeks on vacation. The simple truth is that microcontroller just has not been able to make inroads into this market as the devices have everything in one package, been around a long time, and are UL approved. There are even better timers that are made for outdoor sign lighting displays and store security.
If you do indeed want a battery operated device, you could use ONE QuickStart Board and a 8x relay board from EBay. My personal favorite is to program the Propeller in Forth.
All of the Forths on the Propeller provide a 1 millisecond delay. With PropForth, one cog is used for Serial i/o and 7 remain for you to create separate timing cycles as you wish. I believe that TachyonForth is about the same with 7 cogs available. Pfth might be a little more involved to use multiple cogs.
You now have 6 devices at $20 each or $120 total, and it all is replace with one QuickStart and an 8x relay board. I imagine the nicest thing would be to have a much safer low voltage wiring scheme in your garden. 120VAC doesn't work well for safety around water.
Of course, if you want 6 QuickStart and relay setups, the cost is much higher.
With Forth, you don't really need the LCD display. You can use a laptop computer to program the devices via a USB port and have no display when operating. The QuickStart does provide 8 LEDs that can indicate any status combination you desire.
Second link below is to something similar.
http://www.cpsc.gov/en/Recalls/2009/Intermatic-Recalls-Digital-Timers-Due-to-Shock-Hazard/
http://www.amazon.com/Digital-Timer-Programmable-Lights-Outlets/dp/B0026PZQHY/ref=sr_1_1/182-2863404-8295441?ie=UTF8&qid=1374073623&sr=8-1&keywords=programmable+digital+timer
it has micro second resolution. the timer wont roll over for years. you should have 6 cog left for your application(s)
PM me if you are interested or need help
Now I know why my local big box store does not stock the Intermatic DT17 currently.
Loopy,
What you are describing using a Quickstart is pretty much what I was thinking about.
What I was hoping for is a Programmable timer with relay output that could be used to control
the on/off times of my projects without them being powered by 120Vac.
I'm thinking that building the timer as opposed to connecting a timer to the microcontroller would be a pretty time intensive
project.
Say I want to power up my microcontroller at 5PM on Tues, Thurs, Saturday.
The microcontroller would take care of all needed control of level sensor, pumps running, PIR output control etc.
After a 3 hour long cycle, the timer could disconnect my microcontroller and all sensors from my battery supply.
This is a photo of one of my timer applications:
This one uses 120Vac
I think I'm going to check out PropForth.
Prof, I'll PM you. I need to find the PropForth Syntax documentation so I can read a bit
before trying it.
Perhaps for a reason... http://wemakeitsafer.com/Intermatic-DT17-Heavy-Duty-Digital-Timers-Recall-916252-576331
Here's a plug-in one for $11: http://www.ebay.com/itm/7-Day-dual-outlet-digital-timer-hydroponics-and-indoor-gardening-timer-control/261196357320?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D163%26meid%3D9141380661043966111%26pid%3D100005%26prg%3D1088%26rk%3D4%26rkt%3D4%26sd%3D230768212113%26#ht_786wt_722
Battery-powered sprinkler timers are everywhere, but not necessarily multiple times per day: http://www.ebay.com/itm/NEW-RAY-PADULA-TIME-IT-AUTOMATIC-ELECTRONIC-WATER-GARDEN-HOSE-BATTERY-LAWN-TIMER-/360692512307?pt=LH_DefaultDomain_0&hash=item53faf2f633#ht_2001wt_683
That is the primary reason I suggested Forth. You have a very user-friendly interactive programing environment. Results for something like this can evolve very quickly.
For a week worths of schedules, you just create a word... say WEEK.
If you want a clock with a 365 day calendar, it can easily be done. Or if you just want a weekly cycle, you just have to set the DAY of the week and the actual time.
To call a weeks worth of different timing, you just have a word called Week like this and the main loop would seek out the right day at midnight and use that routine.
: Week Monday Tuesday Wednesday Thursday Friday Saturay Sunday ;
So then you create a word for each day with the timing of events you want to have on and off.
Sure it requires some study to get started, but this isn't C programing and you can test everything as you go.
Besides, if you switch to driving it at the Xtal alone, it will clock slower and save some power for battery use.. but still be accurate at 5Mhz rather than 80Mhz. Why waste juice on delays?
If you want really low power battery operation, use Latching relays. They just require a Pulse to switch state... not continuous power to hold one position.
Be careful, you might just have fun and really like what you have created.
PropForth syntax? Here is the Lexicon PF_QUICK_REFERENCE Ver 5.5_prelim_b.pdf
I know there have been several posted to the forum and I'd be surprised if there isn't a software clock in the OBEX.
Here's a picture of my sprinkler controller. I haven't added a permanent display or case to it yet.
I'm planning on using a wireless fob as the main input device but a few buttons to for setting timers would also work.
A really easy solution would be to use a notebook or netbook as the interface if you don't need to program the timer very often.
If you're interested in using a software clock on the Prop, I could help you find the required objects.
I posted some software on my 6" LED clock project.
If you use any software from that project make sure and let me know. I think there may be a bug or two in the software clock portion and if you want to use it, I'll double check the code for bugs.
As Loopy says, Be careful, you can only go so far with Brodie on the prop. If you really want to study using Brodie, you should use a PC based forth, like F-PC etc. But this path may be tangental.
If you really want to just get down and dirty using the prop, consider doing the examples in the manual (../doc/propforth.htm) and running the extensions from the /extensions directory on actual hardware peripherals. THAT will get your motor running and out on the highway.