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Picture of DIY TiX Clock
Here's my instructable for a DIY TiX clock.  It is powered by an AVR microcontroller.  The display is made up using a piece of reflector grid you find covering office lights, some smoked perspex, a diffuser and a bunch of LED's.  The Idea came from the Tix clocks you can buy at various places on the web, but nothing beats making it yourself.  It is a talking point in the lounge and once you are used to reading it, you can tell the time in a jiffy.


 
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Step 1: The Electronics

Picture of The Electronics
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The first prototype was made using Vero strip board.  The layout on strip board is fairly straight forward.  The Transistors in the top left are row drivers and the IC's on the right are  transistor arrays that are the column drivers (see circuit diagram at the end of instructable for more info).  This allows me to get a bit more current to the LEDs to make them brighter.  The Transistor array IC's can be replaced with transistors if you like.  You will find circuit diagrams and software at the end of this instructable with which I have included an Eagle PCB layout design as well for a single sided board that combines the controller and display board into one.

Note that if you etch your own PCB the LED's are mounted as normal thru hole components but the IC's, links and other components are placed on the copper side of the board.  The LED's and links will need to be mounted first as the AVR covers some of the LED solder points.  Details in the pictures.

Step 2: The Display

Picture of The Display
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The display is made up of a sandwich of the display Board, The square reflector, a diffuser and a smoked perspex window.  You can place a sheet of tinfoil under the LED's to give more reflection, just make sure you cut a hole in tinfoil around a legs of each LED so it doesn't short things out.  I also sanded the lens of each led to distribute the light more.

The first three photos show the strip board version, the remainder the etched PCB version.
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robkirk1 year ago

Compact version. When making the led grid, miss the square separating the digits if you want it smaller.

robkirk1 year ago

i was just looking at different leds and found a type called straw hat leds that spread the light evenly like a lightbulb instead of in a beam, wish i had known of these before i might even redo them with this type in the future when i get bored as my less are very close to the acrylic and you can see the brightness in the middle even with them lightly sanded :)

http://electronics.stackexchange.com/questions/2089/what-is-the-advantage-of-a-straw-hat-led

gweeds (author)  robkirk1 year ago

yes they use them for LED christmas and party lighting. you might end up with a darker circle in the middle, as in the opposite of what you have now.

robkirk gweeds1 year ago

tweeds just a thought but how hard would it be to incorporate a dimming feature either automatic or manual?

robkirk gweeds1 year ago

I've gone for just diffused standard leds this time, see how they work out i shouldn't have to sand them and they are not high intensity so shouldn't be to bright i hope they are bright enough though. oh and i fixed the 3 dim orange less it was either a solder issue or faulty leds as i replaced them and seems fine now.

robkirk1 year ago

Added a few finishing touches today which included blu tak (a form of putty/plasticine) around all the inside grid rows to stop light leakage. Very pleasing to see the squares so crisp now. Also painted the grid black so you can't see it under the smoked acrylic. Added some push buttons on the back by drilling the back piece of acrylic and securing them with lock nuts then soldered onto the main board (my vero board is a mess with jumper wires everywhere and no doubt cold solder joints everywhere and it was 3rd time lucky as I'm no good at soldering). Officially finished and very pleased with it.

oh and i used white baking paper to diffuse in place of the thick tracing paper gweeds suggested and it works very well.

gweeds (author)  robkirk1 year ago

baking paper, now why didn't I think of that. That's what I like about instructables, you see so many different uses for different products! :)

robkirk made it!1 year ago

Finally had time to put the enclosure together it looks sweet with the smoked acrylic and instead of egg crate reflective squares which i found hard to source i used 2cm square plastic grid which is actually a Chinese plate dryer rack. didn't go to the trouble of etching a pcb but managed to fit a vero board inside the enclosure which btw is not as good quality as gweeds enclosure. Thanks to gweeds for helping me and anyone who thinks they can't do this because of limited knowledge of micro controllers i say go for it as i was a complete noob at electronics and managed it from scratch just be prepared to wait for different parts and to learn as you go.

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gweeds (author)  robkirk1 year ago

Looking good Rob!

robkirk made it!1 year ago

finally i have a working prototype, now i have this i shouldn't have to bother you anymore tweeds lol :) many thanks for helping me troubleshoot and even redesigning the schematic because of me. one final question is when i plug my 5 volt breadboard supply into the wall charger it goes mad and all the less flicker. is this to do with the hz being messed up by the 50hz wall transformer? when its plugged into my usb 5v laptop it works fine.

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gweeds (author)  robkirk1 year ago

All good, glad it is going!, I hope the new schematic is a bit easier to follow as well.

nope its working fine actually from a different 5v wall charger :)

robkirk1 year ago

many many thanks i might be speaking to soon but i think i solved it, on that extreme burner program i was not clicking write tick box when programming so the jtag must not have been programmed off!!!! i feel such an idiot! ill post back when i rewire the breadboard again as im only testing that pin atm thanks again gweeds your awesome!

gweeds (author)  robkirk1 year ago
Ah yes, I did that trick too!
repei1 year ago

работает все,кроме порта PB3 pin4. AVR

gweeds (author)  repei1 year ago

Hi there, I have uploaded a updated schematic, that with the current code and JTAG disabled should work.

gweeds (author)  repei1 year ago

Hi there, make sure you have disabled the JTAG interface.

Привет там, убедитесь, что у вас есть интерфейс JTAG отключена

repei gweeds1 year ago

Благодарю за быстрый отклик!Да jtag отключен,иначе не выключался нижний ряд led -3,6,9,12 ....27.Программирую PoniProg через ICSP.У PoniProg переключение FUSE обратное для AVR.На PIN 4 нет логической 0 или 1 ,состояние неопределено,но ЕСЛИ в исходном коде ПОМЕНЯТЬ строку DDRB = & B00000000 на DDRB = & B00001111, то на PIN-4 появляется логическая 1, и столбец led 25,26,27 светит постоянно.Собрано на отладочной плате.-https://www.olimex.com/Products/AVR/Proto/AVR-P40-... Foto в привязанность.Один резистор для драйвера pin4 не видно ,он внизу платы.



jtag off pony.JPGled jtag off.JPGled jtag on.JPGcode.JPG
gweeds (author)  repei1 year ago

Hi again, sorry google has a bit of problems translating that reply. I think I may have mucked up the code and schematic a bit when I uploaded this instructable. Connect the last column to pin 25 instead of pin 4.

repei gweeds1 year ago

Великолепный проект!Благодарю от всего сердца за подробную и быструю техническую поддержку!Это я должен извиниться за беспокойство.всё работает отлично!Но я пока искал причину зашил до смерти один AVR.но не жалко,теперь есть некоторый опыт благодаря Вам!Неплохо было поправить файл для тех кто еще захочет повторить и не имеет достаточного опыта в AVR .А Google лучше переводить оригинальный текст,иначе вообще ничего не понятно .Спасибо!

robkirk1 year ago

ah thankyou so much, to anyone who is reading this I'm using eXtreme burner on windows 7 64 bit and have a usbasp programmer. Ill let you know how i get on and post pics of it. btw did you say the smaller crystal would be ok to use as they are all the same as long as its 32.768 its about half the size of the one on your board and I've used legs 1 and 4 the other legs are not used as i can tell from the datasheet. Thanks again for your kindness and patience at my noob diatribes.

gweeds (author)  robkirk1 year ago

The physical size of the crystal does not matter, it is the frequency that needs to be correct, other wise your clock will run to fast or slow. :)

robkirk1 year ago

I've started on the breadboard prototype just one thing, the blue line connecting 7 pins of the atmega to one of the arrays, does that mean connect each pin to each pin separately or link them altogether? thanks.

gweeds (author)  robkirk1 year ago
Hi there, yeah in the diagram it is show as one line for clarity, but they are individual connections from the array to the AVR
gweeds (author) 1 year ago

Hi Rob, so you need to set the fuse bits as follows, click on the "Configure AVR Clock" button and set as per image 1;

Calibrated Internal RC oscillator

8 MHz

Start-up Time from Power Down (The first recommended option)

NO Options

Then OK that, click on the "Bit Details" for the High Fuse option and UN program the JTAG fuse.

You should see C4 and D9 in low and high fuse respectively.

The 32.768MHz crystal is for the clock only for the Real time clock. It's 32.768 because that can be divided down to 1 Hz pulses for the clock.

As for capacitors, as long as the voltage is higher, it doesn't matter, so you can replace a 10uF 16v with a 10uF 35v.

And the transistor array can be bought from:

http://www.aliexpress.com/wholesale?SearchText=TD6...

take your pick, I have purchased 100's of products from Aliexpress, and only one ever got lost in transit. Those links will also give you some alternative part numbers.

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robkirk1 year ago

thanks a lot for your help. sorry to be a pain but what is the exact crystal model is it a e571? i have ordered one and its the same frequency but a lot smaller than yours i have soldered 2 leads on it to use but not sure if i need a bigger one. also i have a 4.7 uhf capacitor but its rated 63v and yours states 10v although it looks the same size. finally would these arrays work>: http://www.alldatasheet.com/datasheet-pdf/pdf/230752/STMICROELECTRONICS/ULN2003A.html

Neph1x2 years ago
Where i can change blinking time, i wanna make it faster...this is a little bit slow for me..which variable you use for that....Thank you!
gweeds (author)  Neph1x2 years ago
Hi there, after you set the time there is an option to change the blinking time. it cycles in the setup between 1, 5, 10, 15, 30 and 60 seconds. The actual variable that holds this delay time is "Delayvalue". The code sets it to a default of 5 just after all the Pattern definitions.
Grumpy Mike2 years ago
What limits the current through the LEDs?
Is this not going to burn out the LEDs and / or the drivers?
gweeds (author)  Grumpy Mike2 years ago
Nothing does, to get maximum brightness I drive the LEDs with all the current they can source, but because they are multiplexed, they don't burn out. It is quite common to drive LED matrix displays this way to get more brightness. The clock has been running 24/7 since its inception in 2002, never crashed, never needed repair.
mofassir3 years ago
can you please tell me what the JP1 in the schematic is, this is my first time making something so i would appreciate the help
gweeds (author)  mofassir3 years ago
Hi there, JP1 is the main power connector. 5v DC. you can make this a proper DC plug style, or a 2 pin header or just solder the wires to the board.
JP2 is the programming connector
mofassir gweeds3 years ago
thanks, i actually wanted to know how to implement the JP2. for now i have made the connections as specified on the bread board. in place of the JP2 i have simple use the electrically linked vertical column. i hope that will work.
Hi,

Although I have experience doing this kind of stuff back in college, I don't recall how generally to power the breadboard or your board in this case. Did you use a battery? Or is it plugged into the wall with some AC to DC converter between?
gweeds (author)  pinchharmonic3 years ago
I run everything of 5v, using either a wall plug or in the case of a breadboard, I have chopped up a USB lead and just use the 5v from that supplied by the computer.
You can use both. Find a 5v dc transformer if you want to use the wall or use a battery pack. If I do this I would go with the transformer so I will not have to keep changing batteries but it would also be nice to have batteries for when the power goes out.
aessam13 years ago
really nice
this is the first time i see this kind of this clock
was it 12:34 then 12:35?
did i read it right?
gweeds (author)  aessam13 years ago
Thanks, yeah the time in the picture and the start of the video is 12:34
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