Frequency counter and "reset" using 4029 chips

ScottWang

Joined Aug 23, 2012
7,413
Hello miguelpedroso,

0.5 Hz is correct, sorry for the error. You can use any CMOS B series inverters that are available. Sorry for the late reply.

ps. Another nice counter ic is MC14553. It is a complete 3 digit counter and very easy to use.
I also had a six digits counter for labs, and used MC14553 and CD4511, the 4553 is a nice IC, it can make the whole PCB more smaller.

The idea is came from here.

MC14553 datasheet, page 6 offer the circuit diagram of six digits counter used MC14553 and MC14543:
http://www.datasheetcatalog.org/datasheet/motorola/MC14553B.pdf
 

crutschow

Joined Mar 14, 2008
34,833
Below is a digital "one-shot" to do the Load and Reset functions which doesn't use any RC timing elements. I used a slow clock so the timing can be easily seen on the simulation, but you can use a much higher clock speed.

The power and ground pins aren't shown.

Be sure to tie all unused inputs to ground.

Digital One-Shot.gif
 
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Thread Starter

miguelpedroso

Joined Aug 13, 2012
26
ScottWang,
Damn lol :/ Well I didn't know that chip... No I already ordered my chips so I'll stick with my design but I will definitly consider using that chip in the future... Thank you!

crutschow,
Thank you for you solution! :) By the way could you tell me what software did you use to design and simulate?
 

crutschow

Joined Mar 14, 2008
34,833
I used LTspice, which is a free download from Linear Technology. Many on this forum use it. The CD4000 digital models were downloaded from the LTspice users' group, since they are not included in the standard parts library.

Edit: I forgot to note that the one-shot pulse period of my posted circuit is equal to one clock-period.
 

Thread Starter

miguelpedroso

Joined Aug 13, 2012
26
Hello again guys,

After spending a great part of the afternoon soldering, I still could not get this working. I soldered timescope solution (which I reuploaded).

I used a 4011 and I have at least one issue. The problem is that the output of the second nand (pin 4, and the singal to latch the displays) is not a valid CMOS H signal (I checked out with a logic probe and it didn't accuse a CMOS High), even tought it accuses a valid TTL High... :/

I decided to add a 1K pull-up resistor (in the NAND output) to make it valid CMOS signal, but when I inverted the signal again (in the 3rd NAND, to create the parallel load singal) it wouldn't invert it to LOW and would stay at another invalid CMOS level...

And unfortunately I already soldered this so I'm kinda limited in what I can do now :(

Any suggestions or things I could do? I'm using 10nF caps and 10K resistors, just like the the schemattics. I'm only connecting the signals to 1 4511 and 1 4029, so they should be strong enough... :/

The counters are not counting, and the latch displays signal is not a valid CMOS HIGH.

Thank you again!

Miguel
 

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Thread Starter

miguelpedroso

Joined Aug 13, 2012
26
Hello Scott,

Thank you for your reply!

Well truth is I just mounted the same circuit with the 4011 in a breadboard, removed the 4011 from the socket in the veroboard and used some jumpers to connect the "signals" from the breadboard to the right pins in the chip holder in the veroboard and it worked fine!

So it seems to be a problem, not with the circuit itself, but with the circuit soldered in the veroboard... which is really odd because I checked some connections, no shorts, etc... So I don't know what it can be... :/ I'm not very experienced in soldering stuff so I don't know what may be causing the circuit not working. I guess some bad connection, maybe? :/ Dunno...

Edit: Or maybe I do... I'll try it tommorow's afternoon. I think I got an odd "short"... Anyway thank you guys for your help. If you have any suggestions or something please feel free to give them, any feedback from experienced guys is welcome. :)
 
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timescope

Joined Dec 14, 2011
298
Hello miguelpedroso,

Check that you have cut the veroboard tracks under the 4011 ( between pins 1-14 , 2-13 etc) and make sure you have linked the inputs together pins 1-2 , 5-6, 8-9, and 12-13. Clean the flux from the board and check for shorts with a magnifying glass. Check the connections to each pin of the ic.
Timescope
 

Thread Starter

miguelpedroso

Joined Aug 13, 2012
26
Yep I spent a lot of time in the afternoon working on this, I got it working :).

I need to get myself some liquid to clean the flux in the future because my board is completly messed up in flux on the back and as I want a clean and neat circuit I'm soldering a lot of wires in the back, so this is getting confusing. Anyway, I got 2 digits working, so It's counting till 99Hz. I'm currently working in the 3rd display... still 4 to go.

In fact, I need to learn how to make PCB, because soldering the connections from 14 chips, 6 displays, 42 resistors, plus a lot of caps, etc... and then the problem of the poorly cut tracks and flux all around... It's a huge pain.

Thank you again! :)

Miguel
 

timescope

Joined Dec 14, 2011
298
Hi Miguel,
I usually draw a detailed component layout diagram of the circuit before construction. I use 1.0 cm to represent the spacing between the holes on the veroboard (0.1 inch) and draw the tracks like this ----+----+---N----+ with a red pen. The + represents a hole, the N represents a cut in the track and I use a pencil to draw the components so I can erase and move parts around to get a good layout. Hope you get it working.
Timescope.
 

Thread Starter

miguelpedroso

Joined Aug 13, 2012
26
Hello,

I never write anything... got to start! :/. I only think a bit about it and then start soldering. Still I'm with a neat layout in the front. 3 screens working, still 3 to go. :)

Now need to find a way to test these higher frequencies... I have here one 555 oscillator that generates some tones but it's sort of unstable. So far I have been using the other outputs of the 4521 to test the counter till 32 Hz.

0-1Khz: Done :)
 
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