K8LH Novelty Single Chip Clock

[sananh]

Yes it does get hot... Total current comsumption is ~200mA. I think it should be ok. The clock is running little fast compared to my digital watch ~1 second on 24hrs.
Anyway thanks for sharing your work. Sananh

 

[transistor495]

Sananh,
Good work. What kind of pcb etching method did you follow? Did you make it yourself. Can you explain it.

 

[sananh]

I was using PCB etching method see link below.
https://www.electro-tech-online.com/threads/cheap-and-good-pcb-etching-solution.23658/

 

[kumarmahesh]

kindly sent detailed circuit diagram of the clock/ regards kumarmahesh

 

[SteveyD]

Sananh,
Good work. Nice job on your project. Can you provide specific links to the two projects you combined? I know one is at the beginning of this thread.

Mike, K8LH;
Not sure if you recall helping me last year on my led clock project from Sixca.com using the TPIC6B595N's But Its finally completed and ticking away. thanks again

Time to try a new one and I'd like to give this project a run, Do you have a BOM(Bill of Materials) needed for your project?

I'd like to build it as its presented, then make a second one or alter the first in a countdown format which incorporates an alarm.

Cheers
Steve

 

[Mike - K8LH]

Hi Steve,

I prototyped this one chip Clock simply to verify the design. While it works well, the Charlieplexed display brightness is awful. You really should be able to figure out the small BOM from the schematic -- some 1N914 or 1N4148 diodes, three dual-digit non-multiplexed common anode 7 segment displays, seven NPN transistors (2N3904, 2N4401, etc.), four momentary contact push button switches, etc.

Regards, Mike

 

[SteveyD]

Thanks Mike,

Any solution to the display brightness?

 

[Mike - K8LH]

Yes. Use something better than this one chip novelty design (grin).

More later. Gotta run.

 

[Gayan Soyza]

Hi Mike(K8LH) whats the frequency you driving the speaker on RA1?

Are you using any built in Timer modules to that?

 

[Mike - K8LH]

Hi Gayan,

When the "beep task" is running it toggles the "speaker" pin during each 1 msec interrupt. Toggling the speaker at this 1 KHz rate produces a 500 Hz tone.

/********************************************************************
 *  interrupt service routine, 1 msec Timer 2 interrupts            *
 ********************************************************************/

 /*                                                                 *
  *  beep task produces a 500 Hz 'beep' with 1 msec interrupts      *
  *                                                                 */
  if(beepctr)                   // if beep task running
  { porta ^= 1 << spkr;         // toggle speaker pin
    beepctr--;                  // decrement msec counter
  }

 

[Gayan Soyza]

Thanks

Now only I saw it.1mS is a nice rounded value.To drive piezos it needs about 2-3khz to get a smooth sound.It can be easily make this frequency by your software nice work.

 

[RafaelCamacho]

Hi Mike...

In your pictures, we can see some diodes, what is their values?

Thanks.

 

[Mike - K8LH]

The diodes are 1N914 or 1N4148...

 

[RafaelCamacho]

Hi Mike...

It´s very hard to find 16F88... I will try to use a 16F628 to see what happens.

Best.

Rafael

edit:

Congratulations for your project!!

 

[RafaelCamacho]

No sucess to convert it to run in 628A...

 

[Nigel Goodwin]

No sucess to convert it to run in 628A...

Assuming it's not using any non-existant hardware it should be easy, both use the identical 14 bit core.

 

[RafaelCamacho]

I am using BoostC 6.97 in MPLAB IDE 7.50.

I´ve just create a new project using PIC16F628A.

When I try to compile:

Clock.c(20): warning: unknown or invalid pragma (ignored)
Clock.c(21): warning: unknown or invalid pragma (ignored)
Clock.c(167:2): error: unknown identifier 'ansel'
Clock.c(167:2): error: invalid operand 'ansel'
Clock.c(167:8): error: failed to generate expression

So, to compile, I need to comment this:

// ansel = 0; // a2d off, digital i/o

In MPLAB with BoostC, there isn´t a dialog to set the fuses... So, I do this in the programmer, just set PWRTE to ON and other to OFF/DISBALE

In breadboard, I am trying to see what happens using only one display (seconds) and it show only a number 9.

Only these parts:

1x PIC16F628A
1x Xtal 16Mhz
1x 2N3904
2x 22pf
1x DISPLAY COMMON ANODE

Merry Christmas