I'd like build a "day of the week" clock (l.e.d. or better) for my 80yr old uncle (godfather) who suffers from dementia. All it needs to do is display the day of the week. Something small that I can put on his t.v. set (1-1/2" letters).
I would buy one if I could find one but all are analog and he has poor eyes.

Can this be done with ot to much trouble?

Ed

 

It could be done quite easily with a clock chip a microcontroller and some 14 segment displays.

For example a ds1202chip and mostly any controller would be alright for this application.

Do you have any experience with microcontrollers and stuff like that? If not, it would probably be a bit more difficult.

 

Some "Flip clocks" also show the day of the week.
Something like this may be sufficient if the letters are large enough.

http://www.shop.com/Flip_Date_Clock-...p!.shtml?trk=5

 

Hi.
The Radio-Time-of-day clocks are now available for less than $30. I have seen them at Radio Shack and on line. These typically include the temperature, date and day-of-week as well as the time. The problem is, the time is in the largest characters, and the rest of the info is on the small side. Still, these can be found in really large sizes, which may give the other info in sizes large enough to read readilly, but the price goes up quickly.

I did a quick Google on "day of week clock LED project" and got several hits. I only perused the first page of hits. I found nothing immediately useful for your purposes. Still, it led to a few ideas:

1. get a microprocessor development board with an RTC (Real Time Clock) IC on it. You should be able to find articles about harnessing the uprocessor for clock projects, especially using an RTC IC.

2. purchase at least three 5x7 LED character displays. So, you can display "MON, TEU, WED, THU, FRI, SAT and SUN" for the days. If you need more clarity, purchase more of these.

3. Purchase enough shift registers (74HC(T)595) and transistors to drive all the displays, figure one each per segment. The '595 data can be found at:
http://www.ortodoxism.ro/datasheets/.../74HC595PW.pdf
Basically you send out a long stream of bits containing the pattern info for the character displays. On the last bit you enable the outputs to actually light the displays. The transistors drive the column or row, depends on how the display is built.

You would typically use the SHIFTOUT command built into most BASICS supplied with ready built development systems, like Parallax.com's Stamp. The Parallax forums are loaded with talented people who will give lots of good advice all day. Give them a shout about your project.

I am using a board from ELProducts.com, the OEM Atom. The selling point for this board to me is the ability to program it through the serial port. No seperate programmer is needed. It doesn't have an RTC circuit, but it has a great BASIC compiler to go with it. My 'clock' uses the PIC's builtin Timer1. I have it set to run with the divide-8 prescaler. This means there's an interrupt 572 times a second. I keep adding '1' to a second's variable when the timer cycles 572 times This leads to 60 counts to count as one minute; another 60 count to count the hours; a 24 count to track the days... You get the idea. My clock is not terribly accurate, but it does pretty well. You should be able to track the days this way for several months before you have to reprogram it.

So you program in the starting time and day and start the program. Every time midnight comes you zero out the minutes and hours and display the new day. You need to store the patterns for the letters in the names of the days. You use the SHIFT command to send these out to the registers that drive the segments of the display, You use other pins of the processor to drive the transistors.

'Hope that helped! Good luck on your project.
kenjj

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You need one of these, see them on ebay occasionally.

Solari Udine, Dator 5. This one is in German text but English versions are around too.

I got one of those at home in use as a slave clock.
makes interesting clicks at 2359 - 0000 hour changeover.

Regards, Raymond

Attached Images

Solari calendar.jpg (33.7 KB, 14 views)

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Electricity, Electric clocks, Meters and Trains are great.

 

no that wont do, I am actually going to build what I need thanks for all the great tips

 

Here's a couple of photos of a large display clock project I did a few years ago using some salvaged parts. It's driven by an old TI processor and the 5x7's are 2 inches tall (note the 14-pin DIP for scale). I used MAX7219 drivers, one for each display. At full output, it draws over 600 mA! (The colon blinks too, I just couldn't catch it "on")
Jeff

Attached Images

	DSCF0613_c0.jpg (46.4 KB, 18 views)
	DSCF0613_c1.jpg (49.2 KB, 21 views)

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WOW, COOL, nice clock jeff, well done.

I also wondering if you can assist me to build one for me,
detail of schematic, bill of material (part list) and PCB artwork, please !!!

much appriciate for your help

 

Do you want it to show 1 thru 7 or do you want it to show like mon for monday, tue for tuesday etc. Do you want it to also show the time of day also?

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The great thing about electronics is unlimited ways to do the job. The only limit is one\'s imagination. I generally think my way is best.
Show me a different way. I have an open mind.