TTL-ClocK Elektor 1974

This TTL-clock is build in 1974 by me, off a Elektor design which get the time puls from the main power-frequency.

Unfortunately is the time-accuracy too bad and the clock is after a long time off use, I putting it away in a cabinet.

Now after 39 year I  give it a new lifetime, I made the clock-frequency with a Micro-Prosessor programmed in PicBasic. Because these clock can only count forward to set the time, and by wintertime the clock must 1 hour back, that is the same as 23 hour forward and that is nice programming. On the backside I have 2 push-switches, 1 for 23 hour forward and 1 for 1 hour forward. Both 23 hour and 1 hour forward wait time is +/- 5 sec. wait time . The prosessor have a 4 Mhz crystal.
The old time-setting  is not changed, with 50 Hz and 1 Hz. (right hand with push-switch and turn-switch)

 

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The clock on desk in the hobby shop.

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The clock open on the backside, witch in the middle the "Elektor" print.

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The PIC print is in the upper-right in the corner located.
Micro processor is a 12F629 witch a 4 MHz crystal.

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The push switches for the Winter and Summer-time setting

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Up. The test and design at the "breadboard"

Low. Schema, sec. display not made in the clock.

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 Clock description: Unfortunately only in Dutch (up)

 

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Download  Hex code, upper Picture, Asm and PicBasic source program  <== click

 

 I have used single led's as Display and at the follow manner, 3 led's serial, with 2 transistor for a better display from the  6 and the 9 (a and d segment). But the same result you can get by using the driver 74LS247 instead off the 7447 and that one uses less power !

Use only RED led's from 5mm , only that workt with-out manny resistors (1 resistor pro led = 28 pro sigment)

But that is not working with the newer Chinese red led's any more, you need a little more voltage, and that is possible because the driver has a open-collector output with a max. off 15 volt. There is only 5.8 - 6.5 max. necessesary for a bright led. Therefore you need 2 power supply, 1  (one) 5 volt for the logic and 1 (one) 5.8 for the led's.

100 red leds from the E-Bay.com cost only $2.00 - $2.50   <== klik

 

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The new 2014 power supply:

I use a cheap power-adapter 230 volt -> 12Volt  DC  1Amp. (E-bay $3.00), but you can also use a tranformer from 8-9 volt AC  1 A.

Power source is not critical (max 25 volt input) , but more voltage need bigger cooling-plate and you can waste power.

Then I make 5 Volt with a LM7805 voltage regelator and a
LM317 to make 5.8 volt off the 9 volt. R1= 330 and R4,R7= 1110 Ohm

With R2 and R3 you can make 5.3, 5.8 and 6.3 Volt for the intensity of de leds, on de backside are the switches connect to J1.

 

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 2014 The new version of the TTL-clock:

After 40 years I make the same clock with low current components, also without a seconds display but with a micro-processor  for the clock pulse and setting, the TTL in LS (low power / schotty) design and the led current segment at 4 mA. The old 7413 smith-trigger is not easy to buy, so the time-setting is a job for the micro-processor. (see drawing)

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 The transistors T1 and T2 replaced a 1/2 7413 chip because there is not one nand gate over and I donīt want to use a hole chip only for 1 gate, witch only is used to set the clock with S2 en S3. The counters 74LS90  and drivers 74LS247 are cheap on the E-Bay , 10 pcs at $5.70 with shipping from China.

I donīt have a pcb for the new clock, I use a vero-bord and then wiring with a wiringpen.
See
conrad Bestelnr.: 532630 - 89

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10 pcs board (5x7cm) at $1.80 op de e-bay

10pcs 7x9 cm DIY Prototype Paper PCB Panel Universal Board $3.10

      Klick for a description of the pen to make one by your self.

 

A thin plate material (aluminium, pcb or plastic) that you can paint it black for the clock-leds.

My new clock is 11 x 23 cm and 8 cm high led segments.

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CNC Bohrcode to drill all the hole 88 88

 

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Backside    - middle the power and clock PIC with 2 cooling plates  -  right, counters minuts drivers  -  left, hour counters and drivers

 

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Jou see that I the segment at pieces vero-bord has made, easy to replace and no big vero-bord needed, the leds are with 3 in serie powered.

 

Backside cabinet  aluminium 1 cm inside, right side  info card glide in

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 Cabinet from black perspex with a clear red perspex  fore side.

perspex : Polymethylmethacrylaat (PMMA)

It is runnung now and is stable  . . February  4 - 2014

 

 Download  Hex code, with a 12F683, Asm and PicBasic  program  <== klik hex code with 50Hz set-clock

 

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 Wintertijd  = Wintertime    and   Zomertijd =  Summertime   at time zone Amsterdam / Paris

 

 

 The diverence between a 12F629 and a 12F683  is only the memory, 1k or 2k ,you can use both bycause the hex code is not bigger then 1K , but the 12F683 is better and cheaper to buy (80-90 $ cent E-bay.com pcs).

 

 

 

 

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