16x16 LED matrix Real Time Clock interface for the SX52/SX48 and DS1302 RTC

T&E Engineer

Through the good help of many individuals such as JonnyMac, JDOhio, Bean, PJ Allen and Sparks-R-Fun, this project is finished enough to be on the "Completed Projects" page. I will probably modify it a little bit more but this is a good project for anyone that wants to interface a DS1302 RTC to an SX48 or SX52. I will post another project that interfaces a DS1302 to an SX28 with a serial LCD as the display medium. However for this project an SX52 protoboard was used because this interface goes one step further in that it will scroll the Time and Date across a 16x16 LED matrix of 256 LEDs. You can also program in a 16x16 picture. In the case of the attached program, a 16x16 smiley face scrolls up between time and date scrolling cycles. It is also possible to modify this code to scroll down and right but I haven't gotten to that point yet as going left and up was the easiest to start with (thanks to JonnyMac).

It displays a 16x16 LED matrix that I soldered by hand (2 nights to do). However, I have some pre manufactured 2 LED color 8x8 LED matrixes that I will use in the future. Here is a YouTube.com video that I made with the hand soldered LED matrix for demonstration purposes. I have since moved the DS1302 off of the solderless breadboard and soldered it on the SX52 Protoboard - so the video is a little outdated· (since last night). However the video of the display is what's important.

http://www.youtube.com/watch?v=HtUVlkJdNwM

If an SX48 Protoboard is used, then only 1 RA line (RA.3) is available for expansion. If an SX52 Protoboard is used, then 5 RA lines (RA.3 - RA.7) are available for future project usage. One idea is to use some switches to auto program the time and date in.

·HERE IS A LINK TO A 3 COLOR LED VERSION OF THIS PROJECT:
http://forums.parallax.com/showthread.php?p=649643


Post Edited (T&E Engineer) : 6/10/2007 12:09:00 PM GMT

sam_sam_sam

T&Engineer

This a Very nice Project and a Cool

This is....... Cool..est Part.......· 16x16 LED matrix that I soldered by hand

I know that was NOT·an Easy Thing to do but Look Very Nice

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··Thanks for any··that you may have and all of your time finding them

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Sam

T&E Engineer

Thank you. I am actually looking at how to drive the LEDs harder with more current with some 2-3 Amp P channel MosFETs. I am asking the "experts" on this stuff and should have a new posting in·a couple of weeks·with a new design that will hopefully make the LEDs brighter. Currently with this design they are ok but I want to drive more current into them.

I also hope to add my new SX48 OEM module kit (courtesy of RobotWorkshop) to have everything on one board. But I will have to look at the big picture of keeping cost down and may use it as a development tool only.

I am also working on a bi-colored version (software/hardware will take some time to develop). This uses (4) 8x8 LED modules that together are 25% the size of the original one pictured (75% size reduction in display AND 2 colors - red&green)

More to come..

PS: I have some pics to see.

Thanks!


Post Edited (T&E Engineer) : 4/17/2007 1:56:40 PM GMT

sam_sam_sam

T&Engineer



The back of the board looks as neat as the front

Please keep us POSTED as how your Project Comes Along Thanks For sharing with all

of us







····· These two are having way to much Fun··· ··· ·Keep up the good work



·I am looking forward to what you· come up with this part ····

LEDs harder with more current with some 2-3 Amp P channel MosFETs



Sam

Thanks again For sharing with all of us



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Sam

Post Edited (sam_sam_sam) : 4/17/2007 2:29:41 PM GMT

T&E Engineer

I am looking at·2.4 amp Fairchild FDN304PZ P channel FETs·to replace the transistor / resistor row drivers·to start with. I just bought a 5vdc 20 amp power supply on Ebay to provide enough current. From there I can measure how much it will actually draw and recommend the proper current for this circuit. My guess is that it will be 3-5 amps which is a big leap from the 1 amp version I am using on my PDB now.

For the bi-color LED version I will most likely also need to add a few 74HC574 ICs and some additional ULN2803s too.

More to come.

T&E Engineer

I have been working hard on this new version of the 16x16 LED matrix Real Time Clock. It is now in tri-color (Green, Red and Yellow) using (4) 8x8 LED matrix modules I bought on Ebay. ~$17 for 10 modules. I used (4) 74HC573 to control which color is used. I still need to add some push button switches to automatically control the time and date. Since I only have 3 I/O lines left using an SX52, I will have to use a 74HC165. I have already had some good luck·experimenting with·it·this already but I may need some help in the programming.

Eventually I will come up with another design using some serial chips like A6821 or TPIC6C595 to free up a little I/O for use with an SX48 protoboard. The key to my sucess was first the great help on this forum and a couple of others that I have solicited help to understand this concept better.

Here is the YouTube video:

http://www.youtube.com/watch?v=PLGW8knVE1s

More to come...

Let me know what you think. It is certainly one of the hardest projects I have designed and understand.

Thanks!

sam_sam_sam

T&Engineer

This has turn out to be very nice project

I like the fact that info move left to right and the... ..at the end was nice too

A very nice·way to have·a clock to tell time by and use a 16x16 LED matrix·to do with

Very Very Cool


Thanks for sharing with us

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··Thanks for any··that you may have and all of your time finding them

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Sam

T&E Engineer

What's cool is that I think I am the first on this forum at least to have interfaced an SX52 with a DS1302 real time clock and then scroll it on an LED matrix. Most of the code used was either taken as snippets of other code and also solicited programming help. I took a little bit of everything that made sense to come up with a "unique" project.

I can also make anything scroll upwards but it is slightly dimmer (almost unnoticible) because it doesn't utilize the P-FETs as efficiently.

I just need to come up with some ideas on "what" to display. Any message is possible and any single color (green, red or yellow). It "may" be possible to have·multiple colors on·at the same time but that's pretty advanced for the moment. ·It was pretty tight in fitting the 4 proto and perf boards into this case. I also use a "smoked" grey plexiglass sheild to block out light. It does filter the outgoing LEDs a little but adds protection and makes it look cool too.

I will finish the schematics hopefully tomorrow and post them.

Thanks again.


Post Edited (T&E Engineer) : 5/10/2007 3:30:38 AM GMT